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Lazzara, Thomas Dominic. "Self-assembled styrene based alternating copolymer nanotubes : modeling and experiment." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112531.
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The structure and association behaviour of poly(styrene-alt-maleic anhydride) (SMA) and poly(styrene-alt-N,N-dimethylpropylamide) (SMI) polymers were studied using molecular modeling. The conformational studies were carried out at a semi-empirical PM3 level. SMA and SMI polymers were found to associate into nanotubes. These nanotubes have primary, secondary and tertiary structures. The primary structure is the conformation the polymer takes depending on the degree of protonation and its chirality. The secondary structure is the association of many polymers to form a nanotube structure. The tertiary structure is a higher order aggregation between the nanotubes.
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Hadasha, Waled Ajili. "Alternating hetero-arm copolymer molecular brushes as scaffolds for inorganic nano-wires." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79841.
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Thesis (PhD)--Stellenbosch University, 2013.ENGLISH ABSTRACT: This study describes the synthesis and self-assembly of hetero-arm molecular brushes (hetero-arm MBs). These MBs consist of two polymeric side chains (SCs) of different natures, alternatingly distributed along the main chain (backbone). Two different types of hetero-arm MBs were prepared: first, alternating amphiphlic hetero-arm MBs (AMBs), and second, alternating hetero-arm MBs (AHMBs). Hetero-arm AMBs were synthesized via two strategies: (I) via a combination of “grafting through” and “grafting onto”, and (II) via “grafting through”. In approach (I), poly[vinyl benzyl (polyethylene glycol)-alt-N-alkyl-maleimide)] (poly[VB-(PEG12)-alt-N-(CnH2n+1)-MI]) was prepared via radical copolymerization of vinyl benzyl-terminated polyethylene glycol (VB-PEG12) with maleic anhydride (MAnh) (grafting through), which produces graft copolymers with PEG SCs and reactive succinic anhydride repeat units alternatingly distributed along the backbone. These graft copolymers were then modified by nucleophilic substitution (imidization) with alkyl amines (CnH2n+1-NH2) on the succinic anhydride residues (grafting onto). Three different primary amines possessing different alkyl chain lengths (n = 4, 12 and 16) were used in the modification process. In this way, hetero-arm AMBs with different hydrophilic to hydrophobic ratios were obtained. In approach (II), similar hetero-arm AMBs were prepared in a one-step grafting through approach. In this case, poly[VB-(PEG17)-alt-N-(CnH2n+1)-MI] (n = 10, 16 and 20) was prepared via radical copolymerization of VB-PEG17 with N-dodecylmaleimide, N-hexadecylmaleimide and N-icosylmaleimide. Following the synthesis step, self-assembly of these hetero-arm AMBs in arm-selective solvents was investigated in relation to the alkyl chain length. The morphology of the obtained assemblies was characterized by Field Emission gun-Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM) and Fluorescence Microscopy (a fluorescent dye was encapsulated). Cylindrical-like aggregates, length 10 μm and diameter ~ 250 nm, were obtained upon hetero-arm AMBs self-assembly. The second type of hetero-arm MBs was hetero-arm AHMBs, in which the SCs consist of PEG and poly(N,N-dimethylamino-ethyl methacrylate) (PDMAEMA). These hetero-arm AHMBs were prepared via a combination of grafting through and grafting from approaches. In this case, poly[vinyl benzyl-(polyethylene glycol)-alt-N-(poly(N,N-dimethylamino-ethyl methacrylate) maleimide] (poly[VB-(PEG17)-alt-N-(PDMAEMA)-MI) was prepared in the following steps: (1) alternating poly[vinyl benzyl-(polyethylene glycol)-alt-N-(4-hydroxyphenyl) maleimide] (poly[VB-(PEG17)-alt-N-(HPh)-MI]) was synthesized via radical copolymerization of VB-PEG17 with N-(4-hydroxyphenyl) maleimide (N-HPhMI). (grafting through), (2) the hydroxyl sites were esterified with 2-bromoisobutyryl bromide to afford poly [vinyl benzyl-(polyethylene glycol)-alt-N-(4-(2-bromobutyryloxy)phenyl) maleimide] (poly[VB-(PEG17)-alt-N-(BrPh)-MI]) (macroinitiator) and (3) an atom transfer radical polymerization (ATRP) reaction of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) was initiated from the obtained macroinitiator. This approach afforded poly[VB-(PEG17)-alt-N-(PDMAEMA)-MI] hetero-arm AHMBs with two water soluble SCs; however, one is water soluble at all pHs and temperatures (i.e. PEG), while the other is a pH- and temperature-sensitive polymer (i.e. PDMAEMA). Initial attempts were made to fabricate cylindrical organo/silica hybrid materials based on these AMHBs as the organic template and tetra-ethylorthosilicate as the silica precursor. Preliminary results indicate the formation of silica nano-wires, ~ 8 μm in length and ~45 nm in diameter. The self-assembly behavior of these AHMBs in water at a temperature above the lower critical solution temperature of PDMAEMA (> 55 °C) was also investigated. Fibril morphology (~ 30 nm in diameter) was observed. This study addresses initial attempts to fabricate organic/inorganic hybrid materials with controlled size and morphologies via densely grafted hetero-arm molecular brushes.
AFRIKAANSE OPSOMMING: Hierdie studie beskryf die sintese en selfsamestelling van prototipe molekulêre borsels (prototipe MBs). Hierdie MBs bestaan uit twee polimeriese sykettings (SKs) van verskillende aard wat afwisselend langs die hoofketting (ruggraat) voorkom. Twee verskillende tipes van die prototipe MBs is gesintetiseer: eerstens, afwisselende amfifiliese prototipe MBs (AMBs), en tweedens, afwisselende hetero-arm prototipe MBs (AHMBs). Prototipe AMBs is gesintetiseer d.m.v. twee strategieë: (I) deur 'n kombinasie van „enting deur‟ en „enting aan‟ benaderings, en (II) deur middel van „n „enting deur‟ benadering. In benadering (I) is poli[vinielbensiel(poliëtileenglikol)-alt-N-alkiel-maleïenamied)] (poli[VB-(PEG12)-alt-N-(CnH2n+1)-MI]) gesintetiseer deur radikaalkopolimerisasie van vinielbensiel-beëindigde-poliëtileenglikol (VB-PEG12) met maleïenanhidried („enting deur‟) wat entkopolimere produseer met PEG SKs en reaktiewe suksienanhidried herhaaleenhede wat afwisselend langs die ruggraat versprei is. Daarna is die entkopolimere gewysig d.m.v. nukleofiliese substitusie (imiedisering) met alkielamiene (CnH2n+1-NH2) op die oorblywende suksienanhidried („enting op‟). Drie verskillende primêre amiene met verskillende alkielkettinglengtes (n = 4, 12 en 16) is gebruik vir die wysigingsproses. So is prototipe AMBs met verskillende hidrofiliese tot hidrofobiese verhoudings verkry. In benadering (II) is soortgelyke prototipe AMBs gesintetiseer in 'n een-stap „enting deur‟ benadering. In hierdie geval is poli[VB-(PEG17)-alt-N-(CnH2n+1)-MI] (n = 10, 16 en 20) gesintetiseer d.m.v. radikaalkopolimerisasie van VB-PEG17 met N-dodesiel maleïenamied, N-heksadesiel maleïenamied en N-ikosiel maleïenamied. Na afloop van die sintese stap is die selfsamestelling van hierdie prototipe AMBs in spesifieke oplosmiddels in verhouding tot die alkielkettinglengtes ondersoek. Die morfologie van die versamelings is gekarakteriseer deur veld-emissie-geweer-(Eng: field emission gun-)-skandeerelektronmikroskopie (FE-SEM), transmissie-elektronmikroskopie (TEM) en fluoresserende mikroskopie („n fluoresserende kleurstof is ingesluit). Silinderagtige versamelings (lengtes ~10 μm en deursnee ~250 nm) is deur die selfsamestelling van prototipe AMBs verkry. Die tweede soort prototipe MBs is prototipe AHMB, waarin die SKs uit PEG en poli(N,N-dimetielaminoetiel metakrilaat) (PDMAEMA) bestaan. Hierdie prototipe AHMBs is d.m.v. 'n kombinasie van „enting deur‟ en „enting van‟ benaderings gesintetiseer. In hierdie geval is poli[vinielbensiel-(poliëtileenglikol)-alt-N-(poli(N,N-dimetielaminoetiel metakrilaat) maleïenamied] (poli[VB-(PEG17)-alt-N-(PDMAEMA)-MI) gesintetiseer deur van die volgende stappe gebruik te maak: (1) sintese van afwisselende poli[vinielbensiel-(poliëtileenglikol)-alt-N-(4-hidroksifeniel) maleïenamied] (poli[VB-(PEG17)-alt-N-(HPh) -MI) deur midel van radikaalkopolimerisasie van VB-PEG17 met N-(4-hidroksifeniel) maleïenamied (N-HPhMI) („enting deur‟), (2) esterifikasie van die hidroksielgroepe met 2-bromoisobutiriel bromied om poli[vinielbensiel-(poliëtileenglikol)-alt-N-(4-(2-bromobutirieloksi) feniel) maleïenamied] (poli[VB-(PEG17)-alt-N-(BrPh)-MI]) (makro-afsetter) te berei, en (3) die atoomoordrag-radikaalpolimerisasie reaksie van 2-(N,N-dimetielamino)etiel metakrilaat (DMAEMA) wat begin is vanaf die gevormde makro-afsetter. Hierdie benadering gee poli[VB-(PEG17)-alt-N-(PDMAEMA)-MI] prototipe AHMBs met twee wateroplosbare SKs, waarvan een wateroplosbaar is by alle pHs en temperature (d.w.s. PEG), terwyl die ander tipe SK „n pH- en temperatuur-sensitiewe polimeer is (d.w.s. PDMAEMA). Aanvanklike pogings is aangewend om silindriese organo/silika hibriedmateriale te sintetiseer, gebaseer op hierdie AHMBs as die organiese segment en tetraëtielortosilikaat as die silika voorloper. Die voorlopige resultate dui op die vorming van silikananodrade, lengte ~8 μm en deursnit ~45 nm. Die selfsamestellingsgedrag van hierdie AHMBs is ook in water ondersoek by 'n temperatuur hoër as die laer kritieke oplossingstemperatuur van PDMAEMA (> 55 °C). „n Draadagtige morfologie (deursnit ~30 nm) is waargeneem. Hierdie studie beskryf aanvanklike pogings om organiese–anorganiese hibriedmateriale met beheerde groottes en morfologieë via dig-geënte hetero-arm molekulêre borsels te vervaardig.
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Kametani, Yuki. "Strategic Monomer Design for Alternating Copolymers and Sequence-Specific Properties." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263687.
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Malardier-Jugroot, Cécile. "Novel self-assembly of an alternating copolymer into nanotubes : theoretical investigation and experimental characterisation." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85085.
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This thesis is aimed at understanding and fully characterising the association mechanism of an alternating copolymer in water and the effect of the association in solution on the conformation of the polymer chains at the air/water interface.Self-assembly is an elegant and efficient method to obtain well defined and usually defect-free nano-architectures. The association, variety of shapes and properties of block copolymers have been extensively studied. The present study led to a precise understanding of the complex behaviour of large molecules. The polymer studied is an alternating copolymer; poly(styrene- alt-maleic anhydride) (SMA). This polymer has various applications ranging from surface sizing of paper, to nanotechnology and pharmaceutical applications.
The detailed theoretical investigation of the SMA association led to the discovery of a novel way to self-assemble polymer chains, and the prediction and characterisation of a tubular structure formed by this association. The nanotubes are several micrometers long and their conformation shows that the hydrophobic groups are mainly located inside the tube and the hydrophilic groups are mainly on the exterior surface of the tube.
The predicted tubular structure of SMA in solution was also confirmed by neutron scattering experiments. This study showed that the tubes interact forming two-dimensional sheets of tubes and higher order structures. In addition, the SMA association has been shown to be thermally stable.
Furthermore, neutron reflectivity experiments were performed on the SMA solution to determine the influence of the association in solution on the conformation of the polymer at the air-water interface. This study revealed an equilibrium between the conformation of the polymer in solution and at the interface.
Using the knowledge of the association mechanism obtained from the complete theoretical and experimental characterisation of the association of poly(styrene-maleic anhydride) in water and at the air-water interface, a novel application for the polymer has been developed. This application uses the template formed by the nanotubes to form nanowires of intrinsically conducting polymers. Neutron scattering, neutron reflectivity, cryo-TEM and AFM experimental studies characterised the synthesis of the nanowires.
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Nishimori, Kana. "Molecular Design for Precise Sequence Control and Functions of Alternating Copolymers." Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/253306.
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京都大学0048
新制・課程博士
博士(工学)
甲第22470号
工博第4731号
新制||工||1739(附属図書館)
京都大学大学院工学研究科高分子化学専攻
(主査)教授 大内 誠, 教授 秋吉 一成, 教授 竹中 幹人
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DGAM
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WU, DAN. "LIQUID-CORE CAPSULES VIA INTERFACIAL POLYMERIZATION AND ALTERNATING COPOLYMERIZATION." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1179427662.
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Lea, Santa Cinzia Chemical Sciences & Engineering Faculty of Engineering UNSW. "An investigation into the synthesis of poly(co-maleic anhydride/iso-butyl vinyl ether)with RAFT polymerisation." Awarded by:University of New South Wales. Chemical Sciences and Engineering, 2006. http://handle.unsw.edu.au/1959.4/31435.
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Poly (co iso-butyl vinyl ether-alt-maleic anhydride), an alternating copolymer, was synthesised. For this class of copolymers the formation of an electron-donor complex is invoked to explain their microstructure in which the two comonomers strictly alternate. Due to its polarity, this copolymer constitutes a potential additive for imparting hydrophilic properties to a hydrophobic matrix. In order to obtain narrow molecular weight polymers and study the relation between the molecular weight of this additive and its ability to migrate to the host polymer surface, chain transfer agents were introduced in the system and also the Reversible Addition-Fragmentation chain Transfer (RAFT) process was employed. Free radical polymerisation was first carried out to allow for a comparison with the RAFT process and kinetics of copolymerisation was studied by NIR-FTIR and 1H NMR spectroscopy in order to analyse the rate of reaction of each comonomer. Dibenzyl trithiobenzoate, 3-benzyl sulfanyl thiocarbonyl sulfanyl-propionic acid and dibenzyl trithiobenzoate were used as RAFT agents. Results demonstrate that only benzyl dithiobenzoate is able to control the molecular weight of this copolymer and decrease its polydispersity index; possible reasons laying behind this result are discussed. It was also found that, in particular in the presence of benzyl dithiobenzoate, poly(iso-butyl vinyl ether) forms. This is an unusual phenomenon considering that the free radical polymerisation affords alternating copolymers and that iso-butyl vinyl ether is a monomer that polymerises through the cationic process. Experiments were carried out in various solvents in an attempt to counteract this side reaction, but no appreciable correlation between the properties of the solvents and the formation of homopolymer were found. Various hypothesis are considered, however it is likely that, in the conditions adopted, the presence of the RAFT agents alters the equilibrium constant of complex formation favouring the synthesis of the homopolymer. In addition to this side???reaction also inhibition of the copolymerisation reaction was at times encountered and an investigation into this phenomenon was also conducted.
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Polk, William David. "Polydimethylsiloxane Containing Block Copolymers: Synthesis and Characterization of Alternating Poly(Arylene Ether Phosphine Oxide)-B-Siloxane and Segmented Nylon 6,6 -B-Siloxane Copolymers." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/29968.
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Two novel classes of siloxane containing, organic-inorganic block copolymers were prepared using different synthetic approaches. The first copolymers were alternating poly(arylene ether phosphine oxide)-poly(dimethylsiloxane) systems, prepared via oligomeric silylamine-hydroxyl reactions. Secondly, segmented nylon 6,6-poly(dimethylsiloxane) block copolymers were synthesized via a non-aqueous adaptation of the "nylon 6,6 salt" hydrolytic polyamidization, using bis(aminopropyl) dimethylsiloxane oligomer as a co-reactant.
Three series of "perfectly" alternating block copolymers were produced from well characterized hydroxyl-terminated poly(arylene ether phosphine oxide) and dimethylamine-terminated poly(dimethylsiloxane) oligomers, in order to investigate both block length and chemical composition effects. Copolymerization in chlorobenzene resulted in high molecular weight materials capable of forming optically clear, nanophase separated films, which displayed unusual morphologies and good mechanical strength. Thermal gravimetric analysis showed high thermo-oxidative stability and increasing char yield with increasing siloxane content. Additional thermal and mechanical investigations provided evidence of selective phase mixing, particularly at shorter block lengths. Surface analysis showed an enrichment of the siloxane blocks at the air-polymer interface in comparison to the bulk state. This behavior increased in proportion to the length of the parent siloxane oligomers. Evaluation of selected optical properties, e.g., refractive indices, revealed linear trends resulting in values of compositionally weighted averages.
Conversely, a series of nylon 6,6-siloxane copolymers were produced from the polycondensation of preformed propylamine-terminated poly(dimethylsiloxane)s, solid nylon 6,6 salt and a corresponding amount of adipic acid to afford siloxane-amide semi-crystalline copolymers with siloxane content ranging from 10 to ~45 wt%. The characterization of high molecular weight and covalent siloxane-amide linkages was hindered by insolubility. For example, crystallinity of the nylon 6,6 precluded the use of common solution techniques, while the susceptibility of the siloxane blocks towards ionic redistribution prevented the use of strongly acidic solvents. However, development of a novel analytical technique using solid state 13C NMR and liquid-solid extraction provided evidence for the presence of covalent bonding between the dissimilar oligomer chains. Thermal gravimetric analysis of resultant copolymers revealed an increase in char yield with increasing siloxane content, a preliminary indicator of increased fire resistance, which was supported by subsequent qualitative Bunsen burner observations. Differential scanning calorimetry showed retention of the polyamide crystalline melt with levels of siloxane incorporation of up to 45 weight %.
In conclusion, two novel classes of polydimethylsiloxane containing block copolymers have been successfully synthesized, despite the complications created as a result of the polar/non-polar interactions developed between a semi-inorganic polydimethylsiloxane and the hydrocarbon based polyarylene ethers and nylon 6,6.Ph. D.
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Mao, Min. "Synthesis and Characterization of Highly Functional Substituted Stilbene Copolymers and Semi-crystalline Poly(aryl ether sulfone)s." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/29028.
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Novel, highly functional rod-like copolymers have been synthesized by alternating copolymerization of N, N, Nâ , Nâ -tetraalkyl-4, 4â -diaminostilbenes (TDAS) with maleic anhydride. Dynamic light scattering, 2H solid state NMR and persistence length measurement reveal high chain rigidity of the polymer backbone. Double quantum heteronuclear local field solid state NMR spectroscopy (2Q-HLF Solid State NMR) has been employed to investigate the chain structure of 13C labelled copolymer. The torsional angle of the H-13C-13C-H part of the anhydride ring was zero degrees, indicating an all cis configuration of the H-13C-13C-H moiety of the anhydride ring.
Rod-coil block copolymers containing rigid polyampholyte blocks were designed and synthesized by addition-fragmentation chain transfer (RAFT) copolymerization. The rigid polyampholytes blocks were formed by hydrolysis of alternating copolymers and the flexible coil block consists of poly(oligo(ethylene glycol) methacrylate). The rod-coil block copolymers form polyion complex (PIC) aggregates even when the polyampholyte blocks are charge imbalanced. The aggregates did not dissociate upon the addition of high concentrations of NaCl unlike the dissociation of flexible polyampholytes in NaCl solution. These unique solution properties are induced by â like-charge attractions' of the rigid polyampholytic alternating copolymer chains.
An example, of what is birefringent to be a novel class of material, has been prepared which enables the control of the birefringence of a polymer film by controlling the rotation of aromatic groups pendant to the polymer backbone.
A linear rigid bisphenol monomer, 4,4â -dihydroxyterphenyl (DHTP), has been incorporated into poly(aryl ether sulfone)s (PAES) in a study to impart crystallization to these amorphous polymers. Three bisphenols, 4, 4â -isopropylidenediphenol, 4, 4â -(hexafluoroisopropylidene)diphenol and 4,4â -dihydroxybiphenyl have been copolymerized with DHTP and dichlorodiphenylsulfone. Only the segmented polysulfone containing 50% BP and 50% DHTP was semi-crystalline. This PAES had a melting temperature (Tm) 320oC in the first heating cycle of a DSC measurement and the presence of crystallites was confirmed by wide angle X-ray diffraction (WAXS).Ph. D.
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Zhou, Xu. "Synthesis and Characterization of Nanoporous Copolymers with Potential Gas Storage Applications." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51669.
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Nanoporous organic polymers, including hypercrosslinked polymers (HCPs), covalent organic frameworks (COFs), polymers of intrinsic microporosity (PIMs), and conjugated microporous polymers (CMPs) etc., are considered good candidates for potential gas storage and gas separation applications.
Porosities and surface areas of a series of semirigid alternating copolymers, which contained tert-butyl carboxylate-functionalized stilbene or tert-butyl carboxylate-functionalized styrene, and maleic anhydride or tert-butyl carboxylate-functionalized phenyl maleimide, were investigated using nitrogen sorption/desorption isotherms at 77 K and molecular simulations. These alternating copolymers were found to have Brunauer-Emmett-Teller (BET) surface areas in the range of 20-40 m2/g. Surface areas of these alternating copolymers increased as the steric crowding of the polymer backbone increased, which was the result of introducing extra phenyl rings and/or N-phenyl substituent maleimide units. Surface areas were found to increase as the persistence length increased.
A series of HCPs containing functionalized stilbene and N-substituted phenyl maleimide were synthesized via free radical suspension polymerization. The incorporation of these functionalized, chain stiffening, Tg enhancing comonomers raised the Tgs of precursor polymers before they were crosslinked. Surface areas of these HCPs, obtained from nitrogen adsorption/desorption isotherms at 77 K, were up to 1058 m2/g. However, the surface areas of these HCPs were systematically lower than the controls. The high rigidity of the polymer backbone, which was the result of incorporating Tg enhancing comonomer, likely affected the chain mobility of the precursor polymer, decreased the efficiency of post-crosslinking reactions, and thus resulted in lower surface areas.
Amine-functionalized styrene/stilbene polymers were prepared via free radical polymerization or post-modification. Amine-containing silica-based sorbents were prepared using the impregnation method. Sorption of CO2 by these materials was tested using TGA and compared with control samples. Both high amine content and certain levels of surface area were found to be important for a sorbent to achieve high CO2 uptake. Highest CO2 uptake (12 wt%) under our testing condition in these materials was achieved by an amine-containing silica sorbent.Ph. D.
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Al-Samak, Basma. "Alternating ring-opened metathesis copolymers." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343280.
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Medlej, Hussein. "Copolymères à blocs « rigide-rigide » pour les cellules photovoltaïques organiques." Thesis, Pau, 2011. http://www.theses.fr/2011PAUU3027/document.
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Les performances des cellules photovoltaïques organiques de type hétérojonction en volume sont entre autres influencées par les propriétés opto-électroniques du polymère semiconducteur donneur d’électrons. L’objectif de cette thèse était de développer de nouveaux polymères π-conjugués pour permettre une meilleure exploitation du spectre solaire et donc améliorer la photogénération des charges. Pour cela, plusieurs dérivés de polythiophènes comportant des substituants aromatiques phényles ont été synthétisés par la méthode de GRIM, à noter l’homopolymère poly[(3-(4-hexylphényl) thiophène] (P3HPT) et le copolymère à blocs poly[3-(4-hexylphényl)thiophène]-bloc-poly(3-hexylthiophène) (P3HPT-b-P3HT). Nous avons également étudié une nouvelle famille de polymères à faible bande interdite basés sur l’alternance d’unités thiophène et dithiéno[3,2-b:2′,3′-d]silole riches en électrons et 2,1,3- benzothiadiazole pauvres en électrons. Après synthèse des différents monomères, les copolymères alternés ont été ensuite obtenus par polycondensation par couplage de Stille. Les différents matériaux synthétisés ont été d’abord caractérisés par analyse thermogravimétrique et par calorimétrie différentielle à balayage afin d’étudier leurs propriétés thermiques. Ensuite, des caractérisations structurales (en particulier DRX et neutrons), optiques (UV-visible) et morphologiques (AFM) ont été réalisées. A partir des résultats obtenus, nous avons pu évaluer les relations entre les structures et les propriétés des matériaux. Finalement, des cellules photovoltaïques à base des polymères synthétisés ont été réalisées et leurs performances ont été corrélées aux propriétés des matériauxThe performances of organic solar cells based on the concept of bulk heterojunction configuration are strongly influenced by the optoelectronic properties of the electron donor polymer. The aim of this thesis was to develop new π-conjugated polymers to allow a better exploitation of the solar spectrum and thus improving the photogeneration of charges. For this,several polythiophene derivatives substituted by phenyl aromatic groups have been synthesized by the GRIM method, note the homopolymer poly[(3-(4-hexylphenyl)thiophene] (P3HPT) and the diblock copolymer poly[3-(4- exylphenyl)thiophene]-block-poly(3- hexylthiophène) (P3HPT-b-P3HT). We also studied a new family of low band gap polymers based on the alternation of electron-rich thiophene and dithieno[3,2-b:2′,3′-d]silole units andelectron-deficient 2,1,3-benzothiadiazole units. After synthesis of the various monomers, alternating copolymers were then obtained by Stille cross-coupling polycondensation. The different synthesized materials were first characterized by thermogravimetric analysis and by differential scanning calorimetry to study their thermal properties. Then, structural(especially XRD and neutron), optical (UV-visible) and morphological (AFM) characterizations were performed. From the obtained results, we were able to evaluate the relation between structures and properties of materials. Finally, photovoltaic cells based on the synthesized polymers were performed and their performances were correlated to material properties
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Anton, Peter, and André Laschewsky. "Polysoaps via alternating olefin/SO2 copolymers." Universität Potsdam, 1991. http://opus.kobv.de/ubp/volltexte/2008/1721/.
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Contents:
Introduction
Results and discussion
- Monomers studied
- Monomer properties
- Polymerization, copolymer composition and general properties
- Polymer properties in aqueous solution
Conclusion
Experimental part
- Materials
- Copolymerization with S02 (typical procedure)
- Methods
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Christie, David W. "Alternating copolymers containing side-chain liquid crystal groups." Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311158.
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The copolymerisation of N-ethyl maleimide (NEM) with ethyl vinyl ether (EVE) in benzene (Bz) was investigated. The copolymerisation displays a tendency towards alternation but is not alternating and propagation involves the formation of a 1:1 NEM/EVE charge-transfer complex. This complex and the monomer/solvent complexes were investigated by 1H NMR spectroscopic methods. The equilibria were combined mathematically to model the NEM/EVE/Bz system. The copolymerisations of functionalised N-substituted maleimides, N-4-[6-(4'-methoxy-4-azobenzoxy) hexoxycarbonyl] phenylmaleimide (NMeAz6PM) and N-4-[6-(4'-nitro-4-azobenzoxy)hexoxycarbonyl] phenylmaleimide (NNitAz6PM), with styrene (St), 4-vinyl pyridine (4VP), or EVE as the comonomer were studied and the reactivity ratios calculated. The monomer pairs NMeAz6PM/St, NMeAz6PM/4VP and NNitAz6PM/St produce alternating copolymers but NMeAz6PM/EVE does not. The absence of liquid crystallinity in these materials was attributed to the rigidity of the polymer backbone coupled with the low mesogen content arising from the alternating backbone. Blends of amorphous maleimide based copolymers with 6-(4-methoxy-4'-azobenzoxy)hexanoic acid, 4.2, were investigated. The copolymers chosen were believed to be alternating and are the product of the copolymerisation of N-phenyl, N-(4-methoxy) phenyl, or N-(4-hydroxy) phenyl maleimide with St or 4VP. 4.2 is essentially immiscible with the St based copolymers. However 4.2 is miscible with the 4VP based copolymers and liquid crystallinity is induced. This behaviour is attributed to the formation of hydrogen bonds between 4.2 and the pyridyl units of the copolymer backbone. Blends of 4.2 or 6-(4-nitro-4'azobenzoxy)hexanoic acid, 5.2, with copoly(NMeAz6PM-alt-St) or copoly(NMeAz6PM-alt-4VP) were investigated. The limited miscibility and liquid crystalline behaviour of the acid/styrene copolymer blends was attributed to interactions between the mesogens on the copolymer and the acid. However, the enhanced miscibility and liquid crystalline behaviour seen in the pyridine blends can be attributed to the formation of hydrogen bonds between the acids and the pyridyl units of the backbone, in addition to the acid/copolymer mesogen interactions.
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Khansawai, Paveena. "Chemical modification of alkene-carbon monoxide alternating copolymers." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/12362.
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Reactions of isolated carbonyl groups in ethene/propene-carbon monoxide alternating copolymers were accomplished by acid-catalysed condensation with alkene-1,2-diols (ethane-, propane-, butane- and hexane-1,2-diols) affording alkene-dioxolane copolymers. Oximation with hydroxylamine, O- methylhydroxylamine and O-benzylhydroxylamine resulted in complete conversion of the carbonyl groups to their oxime derivatives. In addition, the conversions of polyketoximes, derived from ethene/propene-carbon monoxide copolymers, to 1-acteoxyiminotrimethylene and 1-benzoxyimino-trimethylene polymers were achieved by treatment with acetic anhydride and benzoyl chloride, respectively. Reaction of 1,4-dione units in ethene/propene-carbon monoxide alternating copolymers has been investigated. Paal-Knorr reactions with aniline, benzylamine and glycine ethyl ester yielded poly(alkenepyrrole) derivatives. The conversion of the carbonyl groups in ethene/propene-carbon monoxide alternating copolymers to methoximes allowed directed a-substitution reactions to be carried out on the polymer backbone. Treatment with n-butyllithium followed by addition of electrophiles (e.g. iodomethane, 1-iodopropane, 1-bromobutane, benzyl bromide and allyl bromide) afforded the polymer products in which 20-38% of the a-syn methylene hydrogens were substituted. The syn selectivity of the lithiation process was established b treatment of the polymethoxime with BuLi/[O-2H]methanol and confirmed by the presence of deuterium signal in the 2H-NMR spectrum corresponding to those observed for the model compounds. Beckmann rearrangement reactions of model compounds [2.5-bis(tosyloxyimino)hexane, 2,5-bis(mesyloxyimino)hexane and 2,5-bis(hydroxyimino)hexane] were investigated and resulted in rearrangement products: N,N'-ethanediyl-bis-acetamide, N-acetyl-b-alaninemonomethylamide and N,N'-dimethylsuccinamide.
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Smith, Susan Abenes. "Synthesis and characterization of perfectly alternating segmented copolymers comprised of poly(dimethylsiloxane)s and engineering thermoplastics." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-03022010-020156/.
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Ahmed, Shafique. "Thermal degradation studies of alternating copolymers and their related homopolymers." Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296043.
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Bronk, John M. "Synthesis, characterization and properties of epoxide containing block and alternating copolymers." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-10032007-171915/.
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Brower, Kevin P. (Kevin Peter). "Development of alternating amphiphilic copolymers for targeted delivery applications in cancer." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/62731.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references.
According to the American Cancer Society, approximately 1,479,000 new cases of cancer were expected to be diagnosed, while 562,340 Americans were expected to die from cancer in 2009 alone. Even though advances in early diagnosis and therapy over the past few decades have led to continual decreases in incidence and mortality, cancer remains the second leading cause of death among all Americans. Consequently, further technological development in all areas of cancer detection and treatment are still of great importance not only to the scientific community, but to society itself. To address the shortcomings in current cancer diagnosis and treatment, a novel, highly adaptable, targeted nanoparticle system based on alternating amphiphilic copolymers has been developed having a variety of potential clinical applications. These polymers consist of an alternating copolymer backbone composed of hydrophilic polyethylene glycol-900 (PEG900) and dimethyl 5-hydroxyisophthalate (linker) monomer units. The linker within the backbone polymer has a free hydroxyl group to which a variety of sidechains can be attached, including hydrophobic groups to impart amphiphilicity, targeting ligands, as well as contrast agents for imaging applications. Three major areas of investigation were addressed to develop and evaluate the performance of the proposed amphiphilic alternating copolymers: (1) backbone polymer synthesis, (2) attachment of radioiodine, and (3) targeted delivery in vitro and in vivo. The first step in the production of the alternating amphiphilic copolymers is a chemo-enzymatic condensation polymerization of polyethylene glycol (PEG) and dimethyl 5-hydroxyisophthalate (linker) to produce backbone polymer. Because of their generally low equilibrium constants, condensation polymerizations require effective removal of the condensation byproduct (in this case, methanol) in order to achieve significant increases in molecular weight. The increased viscosities at higher molecular weights not only increase the difficulty of byproduct removal, but may also affect the mixing characteristics as well as the mass transfer of other species in the reaction. The enzymatic polymerization was investigated using both predictive modeling and experiment. The ultimate goal was to increase the molecular weight of the synthesized polymer to allow for increased substitution of the polymer backbone. Key experimental variables were tested in glass flasks typically used in organic synthesis. In these reactions, 4A molecular sieves had the greatest affect on the backbone polymer molecular weight. In particular, addition of sieves, which can act as sinks for both water and methanol, led to a twofold increase in weight-average molecular weight above that observed previously for the enzymatic polymerization. The Protherm, a novel, thin-film reactor was employed in order to improve methanol mass transfer and mixing within the polymer melt. Three separate reactions in the Protherm produced the highest Mw backbone polymer (approximately 20 kDa). A blade speed of 500 rpm with molecular sieves present was able to achieve this Mw in 48 hr. Two separate models were proposed to describe the polymerization, including a homogeneous kinetic model and a Fick's Law mass transfer model. Significant differences were observed between the experimental results and the predictions of the homogeneous model. The mass transfer modeling, which estimated the increase in reactant and methanol surface concentration relative to the concentration in the bulk, was unable to bridge the gap between experiment and model results. Limited knowledge of key model parameters, including the equilibrium constant and methanol solubility, was one proposed explanation for the observed discrepancy. In order to assess the performance of a nanoparticle delivery system in biological applications, a label that is detectable under a wide range of conditions and concentrations must be present within the molecule. Radioiodine was selected because of its multiple potential applications depending on the selected isotope, including 124I for positron emission tomography, 131I for radiotherapy, and 125I for inexpensive, quantitative research applications. A standard protein-labeling technique was adapted for application to the copolymers in this work. The successful adaptation of this procedure for use with our polymers represented the first demonstration in the field of a nanoparticle-forming polymer that was directly labeled with radioiodine without any additional chemicalalterations or intermediate reactions. The process was characterized using a variety of chromatographic techniques and radiometric measurements to confirmed covalent, stable attachment of iodine in a product with high radiochemical purity. The alternating amphiphilic copolymers were combined with an engineered peptide having an extremely high binding affinity for the epidermal growth factor receptor (EGFR), a biomarker prevalent in a variety of human cancers. This high-affinity binder, the E13.4.3 peptide, was developed by collaborator Dr. Benjamin Hackel under the guidance of Professor K. Dane Wittrup. A number of polymer design variables were considered, including the targeting ligand density, identity of the hydrophobic sidechain, polymer molecular weight, and length of the spacer connecting the peptide to the backbone. The ligand density and hydrophobic sidechain identity were chosen for study. Initial studies demonstrated selective uptake of E13.4.3-conjugated polymers into a target-bearing, EGFR-positive human cancer cell line relative to untargeted controls. Preparative gel permeation chromatography (GPC) was used to create high molecular weight, low polydispersity fractions of backbone polymer. Polymers synthesized from these fractions achieved the greatest increase in selective uptake in vitro with a four- to sixfold increase in uptake for E13.4.3-conjugated polymers relative to untargeted controls. Animal studies measured the biodistribution, blood circulation, and tumoral accumulation of various polymer formulations. Statistically significant selective tumor accumulation was observed for two different targeted polymers, each having different targeting ligand density and different hydrophobic sidechains. The E13.4.3-polymers have proven a rich platform for study. Their demonstrated ability to selectively accumulate in targeted tumors combined with their potential use in diagnostic and/or therapeutic clinical applications makes them an attractive option for intensified investigation.
by Kevin P. Brower.
Ph.D.
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Li, Yi. "Sterically Crowded Copolymers Based on Functionalized Stilbenes." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77308.
Full textAbstract:
The research in this dissertation is focused on the synthesis and characterization of sterically crowded, precisely charged polyelectrolytes based on substituted stilbene comonomers.
New sterically crowded polyelectrolytes based on functionalized stilbenes with maleic anhydride or functionalized N-phenylmaleimides were prepared via a "protected" precursor polymer strategy. The polyelectrolyte precursors readily dissolved in organic solvents and were characterized by 1H NMR, SEC, TGA, and DSC. The polyelectrolytes were obtained via simple deprotection chemistries. The use of different combinations of the donor-acceptor comonomer pairs and the alternating copolymerization of these comonomers lead to precise control over charge density and placement of charged groups along the polymer backbone. Analogous styrenic copolymers, for direct comparison to the stilbene structures, were also prepared.
Broad peaks in 1H NMR spectra were observed. There were no thermal transitions measured by DSC below the degradation temperature. A strong polyelectrolyte effect, for both stilbene and styrene copolymers, occurred in deionized water and was suppressed by adding NaCl to the polymer solution. These results are not consistent with "rigid" rod polyelectrolytes in which chain collapse in the presence of added salt and chain expansion on dilution should not be observed. In response to these observations persistence length measurements were conducted on the stilbene and styrene copolymers to assess directly the steric crowding effect of added phenyl groups in stilbene copolymers. Both SEC and SAXS measurements were used to obtain persistence lengths. The results from three different approaches, Bohdanecký, graphical and Sharp and Bloomfield Global, were in good agreement. The persistence lengths of stilbene containing copolymers range from 3 to 6 nm and the added phenyl groups increase the rigidity of the polymer chain by about 30-50%. This puts these polymers into a broadly defined "semi-rigid" category of polymers and is consistent with the solution polyelectrolyte effect observed.
In dilute solution characterization of stilbene containing polyanions, a 2-step dissociation behavior was observed for the two adjacent carboxylic acids in maleic acid containing polyanions. Stilbene polyanion solutions showed high Rh values in deionized water as shown by DLS measurements and a decrease of Rh values followed by aggregation upon gradual addition of salt. Bimodal peaks were observed in SEC measurements with the copolymer of 4-methylstilbene and maleic anhydride. DLS measurements indicated interchain aggregation as the origin of the apparent high molecular weight fraction.
The antiviral activity of the polyanion based on sodium 4-styrenesulfonate and N-(4-sodium sulfophenyl)maleimide was found to be ~50 times higher than the microbicide, sodium poly(styrene sulfonate). The early study of antiviral activities of carboxylated stilbene and styrene polyanions also showed promising results. The synthesis of methyl sulfonate ester-functionalized polyanion precursors was attempted because they can be characterized without the complications caused by directly using charged sulfonate groups.Ph. D.
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Savage, Alice. "Synthesis and Solution Properties of Semi-rigid Polyelectrolytes and Polyampholytes." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/50820.
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The incorporation of substituted stilbenes in copolymers affects the resulting solution properties and their controlled radical polymerizations. Substituted stilbene monomers readily polymerize in an alternating fashion with acceptor comonomers such as maleic anhydride and maleimide. These sterically crowded polymer backbones are classified as semi-rigid. As this is an uncommon category of polymer backbone rigidity, examples of semi-rigid and rigid polyzwitterions in the literature were reviewed as well as stilbene-containing semi-rigid polymers. Using a deprotection strategy, anionic polyelectrolytes and polyampholytes of stilbene-maleic anhydride copolymers were synthesized and characterized by first synthesizing organic-soluble polymer precursors. Solution shear rheology and statistical segment length measurements reveal that carboxylated polyanions containing stilbene and maleic acid remain semi-rigid in aqueous solutions. It was found that these semi-rigid polyanions exhibited excellent anti-HIV activity possibly due to their more extended polymer chains. This was the first time that intrinsic polymer rigidity was introduced as a possible design parameter for microbicidal applications. Reversible addition fragmentation chain transfer (RAFT) polymerization techniques were used to copolymerize 4-diethylaminostilbene with maleic anhydride. These new semi-rigid copolymers were incorporated into double hydrophilic block copolymers (DHBCS) containing semi-rigid and flexible segments. The subsequent solutions properties of these DHBCs were evaluated with respect to pH and salt responsiveness. Notably, the DHBCs exhibited a "like-charge" attraction as ionic strength increased which was attributed to the semi-rigid character of the polyampholyte block copolymer.Ph. D.
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Huang, Jing. "Functional Polymers Containing Semi-Rigid Alternating Sequences." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/89884.
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Alternating copolymers represent a special class of copolymers in which the two comonomers copolymerize in a regular alternating sequence along the polymer chain. Of particular interest in our group are the stilbene-maleic anhydride/maleimide alternating copolymers. These copolymers possess sterically congested backbones and precisely placed functional groups arising from the strictly alternating copolymerization. The research in this dissertation is focused on the synthesis, characterization, and potential application of functionalized copolymers that contain semi-rigid alternating copolymer sequences.
The fluorescence properties of a series of non-conjugated, tert-butyl carboxylate functionalized alternating copolymers were investigated. Extraordinarily high fluorescent intensity with excellent linearity was observed for the di-tert-butyl group-containing stilbene and maleic anhydride alternating copolymer in THF. We attributed the origin of the strong fluorescence to the “through space” π – π interactions between the phenyl rings from the stilbene and C=O groups from the anhydride. The fluorescence was maintained when the copolymer was deprotected and hydrolyzed and the resulting carboxylic acid-functionalized copolymer was dissolved in water at neutral pH.
The tert-butyl carboxylate functionalized alternating copolymer sequences were incorporated into highly crosslinked polymer networks using suspension polymerization. After removing the tert-butyl groups by acidic hydrolysis, the surface area of the networks increased significantly. Using this facile two-step strategy, we were able to achieve nanoporous polymers with BET surface area up to 817 m2/g and carboxylic acid-functionalized surfaces. The BET surface area of deprotected polymers increased with increasing crosslinking density, and the stilbene-containing polymers showed systematically higher BET surface area than the styrene-containing polymers due to the stiffness of the alternating sequences. The resulting nanoporous polymers have potential to be employed as solid sorbents for CO2.
The same tert-butyl carboxylate functionalized alternating copolymer sequences were also incorporated into microgels via miniemulsion polymerization. The miniemulsion technique ensured the successful synthesis of microgels with ~100 nm diameter using solid stilbene and maleimide monomers. The resulting tert-butyl carboxylate-containing microgels were converted into carboxylic acid-containing aqueous microgels by acid hydrolysis. These aqueous microgels showed good and reversible lead and copper ion adsorption capacities.
Amine-functionalized nanoporous polymers were synthesized by the post-modification of highly-crosslinked divinylbenzene-maleic anhydride polymers. High amine-contents were achieved by covalently attaching multiamines to the acid-chloride functionalized polymer surface. The resulting polymers showed medium to high BET surface areas (up to 500 m2/g) and high CO2 capture capacities.PHD
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Schubert, Marcel. "Elementary processes in layers of electron transporting Donor-acceptor copolymers : investigation of charge transport and application to organic solar cells." Phd thesis, Universität Potsdam, 2014. http://opus.kobv.de/ubp/volltexte/2014/7079/.
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Donor-acceptor (D-A) copolymers have revolutionized the field of organic electronics over the last decade. Comprised of a electron rich and an electron deficient molecular unit, these copolymers facilitate the systematic modification of the material's optoelectronic properties. The ability to tune the optical band gap and to optimize the molecular frontier orbitals as well as the manifold of structural sites that enable chemical modifications has created a tremendous variety of copolymer structures. Today, these materials reach or even exceed the performance of amorphous inorganic semiconductors. Most impressively, the charge carrier mobility of D-A copolymers has been pushed to the technologically important value of 10 cm^{2}V^{-1}s^{-1}. Furthermore, owed to their enormous variability they are the material of choice for the donor component in organic solar cells, which have recently surpassed the efficiency threshold of 10%.
Because of the great number of available D-A copolymers and due to their fast chemical evolution, there is a significant lack of understanding of the fundamental physical properties of these materials. Furthermore, the complex chemical and electronic structure of D-A copolymers in combination with their semi-crystalline morphology impede a straightforward identification of the microscopic origin of their superior performance. In this thesis, two aspects of prototype D-A copolymers were analysed. These are the investigation of electron transport in several copolymers and the application of low band gap copolymers as acceptor component in organic solar cells.
In the first part, the investigation of a series of chemically modified fluorene-based copolymers is presented. The charge carrier mobility varies strongly between the different derivatives, although only moderate structural changes on the copolymers structure were made. Furthermore, rather unusual photocurrent transients were observed for one of the copolymers. Numerical simulations of the experimental results reveal that this behavior arises from a severe trapping of electrons in an exponential distribution of trap states. Based on the comparison of simulation and experiment, the general impact of charge carrier trapping on the shape of photo-CELIV and time-of-flight transients is discussed.
In addition, the high performance naphthalenediimide (NDI)-based copolymer P(NDI2OD-T2) was characterized. It is shown that the copolymer posses one of the highest electron mobilities reported so far, which makes it attractive to be used as the electron accepting component in organic photovoltaic cells.par
Solar cells were prepared from two NDI-containing copolymers, blended with the hole transporting polymer P3HT. I demonstrate that the use of appropriate, high boiling point solvents can significantly increase the power conversion efficiency of these devices. Spectroscopic studies reveal that the pre-aggregation of the copolymers is suppressed in these solvents, which has a strong impact on the blend morphology.
Finally, a systematic study of P3HT:P(NDI2OD-T2) blends is presented, which quantifies the processes that limit the efficiency of devices. The major loss channel for excited states was determined by transient and steady state spectroscopic investigations: the majority of initially generated electron-hole pairs is annihilated by an ultrafast geminate recombination process. Furthermore, exciton self-trapping in P(NDI2OD-T2) domains account for an additional reduction of the efficiency. The correlation of the photocurrent to microscopic morphology parameters was used to disclose the factors that limit the charge generation efficiency. Our results suggest that the orientation of the donor and acceptor crystallites relative to each other represents the main factor that determines the free charge carrier yield in this material system. This provides an explanation for the overall low efficiencies that are generally observed in all-polymer solar cells.Donator-Akzeptor (D-A) Copolymere haben das Feld der organischen Elektronik revolutioniert. Bestehend aus einer elektronen-reichen und einer elektronen-armen molekularen Einheit,ermöglichen diese Polymere die systematische Anpassung ihrer optischen und elektronischen Eigenschaften. Zu diesen zählen insbesondere die optische Bandlücke und die Lage der Energiezustände. Dabei lassen sie sich sehr vielseitig chemisch modifizieren, was zu einer imensen Anzahl an unterschiedlichen Polymerstrukturen geführt hat. Dies hat entscheidend dazu beigetragen, dass D-A-Copolymere heute in Bezug auf ihren Ladungstransport die Effizienz von anorganischen Halbleitern erreichen oder bereits übetreffen. Des Weiteren lassen sich diese Materialien auch hervorragend in Organischen Solarzellen verwenden, welche jüngst eine Effizienz von über 10% überschritten haben. Als Folge der beträchtlichen Anzahl an unterschiedlichen D-A-Copolymeren konnte das physikalische Verständnis ihrer Eigenschaften bisher nicht mit dieser rasanten Entwicklung Schritt halten. Dies liegt nicht zuletzt an der komplexen chemischen und mikroskopischen Struktur im Film, in welchem die Polymere in einem teil-kristallinen Zustand vorliegen. Um ein besseres Verständnis der grundlegenden Funktionsweise zu erlangen, habe ich in meiner Arbeit sowohl den Ladungstransport als auch die photovoltaischen Eigenschaften einer Reihe von prototypischen, elektronen-transportierenden D-A Copolymeren beleuchtet. Im ersten Teil wurden Copolymere mit geringfügigen chemischen Variationen untersucht. Diese Variationen führen zu einer starken Änderung des Ladungstransportverhaltens. Besonders auffällig waren hier die Ergebnisse eines Polymers, welches sehr ungewöhnliche transiente Strom-Charakteristiken zeigte. Die nähere Untersuchung ergab, dass in diesem Material elektrisch aktive Fallenzustände existieren. Dieser Effekt wurde dann benutzt um den Einfluss solcher Fallen auf transiente Messung im Allgemeinen zu beschreiben. Zusätzlich wurde der Elektronentransport in einem neuartigen Copolymer untersucht, welche die bis dato größte gemesse Elektronenmobilität für konjugierte Polymere zeigte. Darauf basierend wurde versucht, die neuartigen Copolymere als Akzeptoren in Organischen Solarzellen zu implementieren. Die Optimierung dieser Zellen erwies sich jedoch als schwierig, konnte aber erreicht werden, indem die Lösungseigenschaften der Copolymere untersucht und systematisch gesteuert wurden. Im Weiteren werden umfangreiche Untersuchungen zu den relevanten Verlustprozessen gezeigt. Besonders hervorzuheben ist hier die Beobachtung, dass hohe Effizienzen nur bei einer coplanaren Packung der Donator/Akzeptor-Kristalle erreicht werden können. Diese Struktureigenschaft wird hier zum ersten Mal beschrieben und stellt einen wichtigen Erkenntnisgewinn zum Verständnis von Polymersolarzellen dar.
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Li, Siyuan. "INTERFACIAL PHENOMENA IN COPOLYMER MEMBRANES SWOLLEN BY SURFACTANTS AND MICROWAVE SYNTHESIS OF METAL OXIDE-CARBONS." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1618249966415808.
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Lessard, Benoît. "Advances in Nitroxide-mediated controlled radical polymerization from Poly(Methacrylate)s to perfectly alternating copolymers." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110396.
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Nitroxide mediated controlled radical polymerization (NMP) has been utilized since the early 1990s, as a simple and robust technique for the synthesis of various new polymeric architectures. Since the development of second generation initiators based on SG1 and TIPNO stable radicals, NMP is no longer restricted to the polymerization of just styrenics as it was initially and can now homopolymerize a plethoraof monomers such as acrylates and acrylamides. In this thesis, several advances in NMP due to these second generation initiators, were explored. The homopolymerization of methacrylates, by NMP, results inexcessive irreversible termination due to the elevated concentration of free radicals generated in the initial stages of the polymerization. However, the use of a small amount of a "controlling" comonomer can be used to control the copolymerization, as characterized by a linear increase in number average molecular weight (Mn), versus conversion (X) and a narrow molecular weight distribution (Mw/Mn < 1.5). The use of styrene ( 10 mol%) as a "controlling" comonomer for ethyl methacrylate, n-butyl methacrylate and tert-butyl methacrylate resulted in a controlled copolymerization of pseudo-"living" random copolymers characterized by a narrow molecular weight distributions (Mw/Mn = 1.2-1.5). In addition to styrene, 9-(4-vinylbenzyl)-9H-carbazole) (VBK) was used as a "controlling" comonomer for methyl methacrylate and 2-(dimethylamino)ethyl methacrylate, requiring as little as 1-2 mol% VBK relative to methacrylate, resulting in a controlled pseudo-"living" polymerization. In the second part of the thesis, NMP was utilized to control the copolymer microstructure. When using a non-equimolar feed of maleic anhydride (MA) and styrene (S), the synthesis of poly(MA-alt-S)-b-poly(S) block copolymers characterized by narrow molecular weight distributions (Mw/Mn = 1.3) where one block consisted of alternating MA and S monomers, was possible when the polymerization temperature was kept below 90 C. Finally a poly(ethylene-co-butylene)-SG12 initiator was synthesized and was used to successfully polymerize S and S/MA mixtures. The final poly(ethylene-co-butylene)-poly(MA-alt-S)2 block copolymers were tested as compatibilizers in blends with nylon-6.L'utilisation de la polymèrisation radicale contrôlée en présence de radicaux nitroxyde (NMP) a débuté vers les annèes 1990s. Cette technique est simple et robuste, portant facilement à la synthèse de diverses nouvelles architectures de polymères. Grâce au développement d'initiateurs de deuxième génération basés sur radicaux stables de SG1 et de TIPNO, l'NMP n'est plus limité à la polymérisation des styrènes et peut maintenant homopolymériser une varietée de monoméres tels que des acrylates et des acrylamides. Dans cette thèse, plusieurs développements de l'NMP dus à ces initiateurs de deuxième génération, ont été explorés. L'homopolymérisation des methacrylates, par NMP, a pour consèquence un excés de terminaisons irréversibles en raison de à la concentration élevée de radicaux libres produits au début de la polymérisation. Cependant, une petite quantité de comonomère "contrôlant" peut être utilisée pour contrôler la copolymèrisation, donnant comme résultat une augmentation linéaire de la masse molaire moyenne en nombre (Mn) avec la conversion (X) ainsi que des copolymères qui possèdent une distribution moléculaire étroite (Mw/Mn < 1.5). Le styrène ( 10 mol%) a été utilisé comme comonomère "contrôlant" pour la synthèse du méthacrylate éthylique, le méthacrylate n-butylique et le méthacrylate de tert- butyl. Dans tous les cas la copolymèrisation était contrôlée, donnant comme résultat un copolymère qui est "vivant" et qui possède une distribution moléculaire étroite (Mw/Mn = 1.2-1.5). En ajout du styrène, 9-(4-vinylbenzyl)-9H-carbazole) (VBK) a été employé comme comonomère "contr^olant" pour le méthacrylate méthylique et le méthacrylate de 2-diméthylaminoéthyle, mais cette fois exigeant que 1-2 mol% de VBK par rapport aux méthacrylates, ayant comme résultat une copolymèrisationcontr^olée et des copolymères _naux qui sont "vivants". Dans la deuxième partie de la thèse, NMP a été utilisé pour contrôler la microstructure de divers copolymères. En employant une formulation non-équimolaire d'anhydride maléique (MA) et de styrène (s), la synthèse de blocs copolymères poly(MA-alt-S)-b-poly(S) ayant une distribution moléculaire étroite (Mw/Mn = 1.3) a été réalisée lorsque la température de polymérisation était maintenue en dessous de 90C. Finalement l'initiateur poly(éthyléne-co-butyléne)-SG12 a été synthètisé et employé pour la polymèrisation de S et de mélanges de S/MA. Finalement, des copolymères en bloc poly(éthyléne-co-butyléne)-poly(MA-alt-S)2 ont été examinés comme compatibilisateur de mélanges avec le nylon-6.
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Singh, Gurpreet. "Dynamic Thermal Field-Induced Directed Self-Assembly of Block Copolymer Thin Films." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1372120753.
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Miller, Michelle Teresa. "In vitro evaluation of cytotoxicity and cellular uptake of alternating copolymers for use as drug delivery vehicles." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51673.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
Cancer is the collective group of diseases distinguished by uninhibited growth and spread of abnormal cells. It often results in death if the spread is not controlled. Most cancers are treated by surgery, radiation, chemotherapy, hormones, or immunotherapy. However, currently there are many issues with these forms of treatment, namely the lack of ability to consistently remove the entire tumor and the side effect of killing normal cells during the treatment process. Therefore there has been an increased interest in targeted drug delivery to tumors to specifically kill cancer cells. We have developed a highly adaptable amphiphilic alternating copolymer system that self-assembles into micelles for therapeutic delivery applications in cancer. The synthetic scheme includes the enzymatic polymerization of multifunctional linker molecules (dimethyl 5-hydroxyisopthalate) with poly(ethylene glycol). This chemoenzymatic synthesis is much faster and more convenient than an entirely chemical synthesis. Subsequent synthetic steps have been developed to attach ligands (for targeting), perfluorocarbons (19F MR imaging), fluorescent dyes (NIRF imaging), and radioiodine (nuclear imaging and radioimmunotherapy) to the backbone. Attachment of hydrocarbon or perfluorocarbon sidechains provides amphiphilicity to produce the multimodal self-assembling micelles. Additionally, encapsulation procedures for chemotherapeutic agents, doxorubicin and paclitaxel, have been established.
(cont.) These unique alternating copolymer micelle nanoparticles were designed as delivery vehicles targeted to human cancer cells expressing the underglycosylated mucin-1 antigen, which is found on almost all epithelial cell adenocarcinomas, by use of the peptide EPPT or the folate receptor (FR) by use of folate. Development of the synthetic schemes has been coupled with in vitro toxicity experiments using various cell viability assays to minimize the toxic effect of these copolymer structures. Overall the polymers used in this study were largely non-toxic when studied in vitro. The non -toxic polymers were brought forward into drug delivery and uptake experiments. Cell death due to doxorubicin increased with encapsulation in these alternating copolymers and increased slightly more with the addition of targeting ligand to the encapsulating polymer. Encapsulating paclitaxel in polymer also increased cell death as compared to free drug. These results demonstrate that these alternating copolymers have had some success as drug delivery vehicles. Other in vitro studies included the investigation of cellular uptake by 125I or 3H radioactive analysis and fluorescence confocal microscopy. Microscopy images of the fluorescently labeled polymer alone demonstrated that the polymer was likely confined to vesicles within the cytoplasm and it was not found in the nucleus, but encapsulated doxorubicin was shown to be largely confined to the nucleus.
(cont.) Theoretical models of polyvalent binding were employed to guide the design of the targeting polymers, however, the polymers used in this study appeared largely non-specific for the targeted cells when studied in vitro. The cellular uptake of polymer targeted with EPPT was twice that of untargeted polymer, although the difference was not statistically significant. For polymers containing folate, regardless of the amount of folate attached, the length of the spacer used, or the type of radioactive label used, the uptake did not decrease in the presence of an excess of folate, indicating a high amount of non-specific uptake for all folate-containing polymers. When all of the folate-containing polymers were used to competitively inhibit 3Hfolate, almost all inhibited the uptake by 1 or 2 orders of magnitude, suggesting that the targeted polymers bind to the FR. An in-depth study of the cell-association of these polymers clarified that polymer was taken up non -specifically in high amounts. An excess of unlabeled folate, up- or down-regulation of the FR, and cleaving the FR did not measurably affect polymer uptake, but did alter folate uptake. It was also determined that a low level of polymer does bind to the FR. The amount of surface bound polymer was much lower than the total uptake of polymer in folate-free media for each polymer concentration investigated. In addition, the amount of surface bound folate and polymer decreased when the FR was cleaved, confirming the attachment of polymer to the FR. Light scattering measurements showed that polymers that contain folate form aggregates of multiple polymers chains.
(cont.) It is possible that this aggregation was allowing a portion of the folate ligands to be hidden in the aggregate and unavailable for binding to the FR, the most likely mechanistic cause of the failure of the folate-containing polymers to demonstrate targeting. The versatility of these polymer constructs allows for continued optimization of a targeting delivery system for drugs and imaging agents as lessons discovered from passed studies are incorporated into the design. Initial in vivo biodistribution studies were begun to explore the behavior of these polymers in mouse models of human cancers. The alternating copolymers used in this study do accumulate in tumors in vivo, comparable to the levels of accumulation observed in the literature. It is desirable to minimize the accumulation in other organs, while maximizing the accumulation in the tumor tissue. Therefore, this preliminary study warrants continued investigation of our polymer platform as a delivery vehicle in vitro and in vivo.
by Michelle Teresa Miller.
Ph.D.
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Studnicki, Lisa Helen [Verfasser], Elisabeth [Gutachter] Klemm, and Oskar [Gutachter] Nuyken. "Synthesis of new alternating block copolymers with tailored π-conjugated blocks and non-conjugated aliphatic spacers / Lisa Helen Studnicki ; Gutachter: Elisabeth Klemm, Oskar Nuyken." Jena : Friedrich-Schiller-Universität Jena, 2007. http://d-nb.info/1205740864/34.
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Legros, Mathilde. "Synthèse et caractérisation de nouveaux polythiophènes porteurs de groupes C60 pour une application solaire photovoltaïque organique." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00664997.
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L'efficacité des cellules photovoltaïques organiques est influencée par la morphologie du mélange composant la couche active. L'objectif de cette thèse a été d'élaborer un agent compatibilisant pour stabiliser la morphologie du mélange P3HT:PCBM. Nous avons choisi de synthétiser des copolymères alternant motifs C60 et polythiophène pour améliorer la miscibilité entre P3HT et PCBM. Les copolymères ont été réalisés par polycondensation d'un dérivé C60 avec plusieurs oligothiophènes régioréguliers de difonctionnalité contrôlée. Une attention particulière a été accordée aux conditions de polycondensation qui ont été optimisées pour favoriser de hauts degrés de polymérisation. Les caractérisations structurales, optiques et électrochimiques des matériaux ont été réalisées. Leur effet compatibilisant a été évalué en caractérisant la morphologie de la couche active par des mesures en cellules photovoltaïques, des observations par microscopie à force atomique et des calculs d'énergies de surface.
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Rosenthal-Kim, Emily Quinn. "Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1386525065.
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Hung, Chi-Hang, and 洪啟航. "The Research of Photoelectric in Alternating Thiophene Copolymer and Nanocomposites." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/yfycb9.
Full textAbstract:
碩士國立臺北科技大學
有機高分子研究所
99
Conjugate polymers are organic polymers that conduct electricity. Such compounds may have metallic conductivity or can be semiconductors. The biggest advantage of conductive polymers is their processability, mainly by dispersion. Polythiophene is a very important material that is used in polymer solar cell. The thermal stability is very important for solar cell during the irradiation of the sun. Therefore, a new type of polythiophene is synthesized. The copolymer manifest better stability than the unmodified polythiophene. In this experiment, polythiophene with carboxylate functional groups is synthesized. Their physical properties are investigated by Fourier Transform Infrared Spectroscopy, UV-Visible Spectroscopy, and Nuclear Magnetic Resonance. The thermal stability is due to the crosslinking reaction occurred after the siloxane freatments. Use carboxylate thiophene and thiophene to synthesize alternating copolymer. Their physical properties are investigated by Four-point probe Conductivity Meter and Fourier Transform Infrared Spectroscopy.
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Chen, Pin-Ying, and 陳品穎. "Alternating Copolymers Containing Bipyridine and Phenylenevinylene for Chemosensor Applications." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/94917358412194636283.
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碩士國立臺灣科技大學
材料科學與工程系
102
The organic conjugated polymer has been rapidly developed in the past decade, and the application of conjugated polymer to the chemosensor has attracted considerable attention. Fluorescence conjugated polymer chemosensors for metal ions sensing which containing bipyridine units and phenylenevinylene moieties were prepared in this thesis. Nitrogen-based ligands such as 2-2’-bipyridine can effectively coordinate a variety of metal ions. The polymer conformation changed due to the coordination with metal ions, and the optical properties present something different subsequently. Addition of heavy metal ions to the fluorescent polymer solution and dipping the polymer films to heavy metal ions solution generated a different extent of fluorescent quenching and absorbance red-shift, and these could be applied to the detection of the presence of transition metal in our environment.
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Shih, Tsung-yu, and 施宗佑. "Alternating copolymers containing fluorene and oxadiazole derivatives for chemosensor applications." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/46067640974960781026.
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碩士國立臺灣科技大學
材料科學與工程系
100
The novel alternating copolymers, poly(9,9-dioctylfluorene) with pendant 2-pyridyl- and 2-pyrimidyl-1,3,4-oxadiazole, were synthesized through palladium-catalyzed Suzuki coupling reaction. The thermal, optical and electrochemical properties of these polymers are substantially affected by the heteroaryl substituted oxadiazole groups in the side chain. In addition, it is interesting to note that the significant bathochromic effect was found which results in different absorption spectra in both solution and solid states. The fluorescence quenching ratios were found to be directly related to the loading of metal ions and can be modeled by a Stern-Volmer type relationship. Due to the photoinduced electron transfer mechanism, the polymers act as the turn-off fluorescent chemosensor. The sensing behaviors to various metal ions such as nickel(II) cations, zinc(II) cations, cupper(II) cations and mercury(II) cations revel that the polymers are highly sensitive to nickel(II) cations and cupper(II) cations. The results show that these two polymers can act as the potential sensory material for the appropriate detection of sensitive and selective sense of metal ions.
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Chen, Wen-Hao, and 陳文豪. "Folding of Alternating Dialkylsilylene-Spaced Donor-Acceptor Copolymers: The Oligomer Approach." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/81403560185755986690.
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碩士國立臺灣大學
化學研究所
100
A series of oligomers with donor and acceptor moieties divided by different dialkylsilylene spacers (Me2Si- vs iPr2Si-) have been designed and synthesized to inspect the folding behavior of the corresponding copolymers by investigating their photophysical properties. 4-Aminostyrene moiety was chosen as the donor and stilbene moiety was selected as the acceptor. Sequential Rh-catalyzed hydrosilylation of terminal alkyne with silylhydride afforded these oligomers. Terminal alkynes were prepared by Sonogashira reaction. Silylhydrides were introduced by lithiation of corresponding aryl bromides with nBuLi followed by silylation with dialkylchlorosilanes. Unsymmetrical stilbenes and bisalkyne were delicately designed and synthesized for constructing these oligomers. Both local excited (LE) emission of the acceptor chromophore and emission from the charge-separated state (CT emission) have been observed in Me2Si-spaced oligomers, just like that of Me2Si-spaced copolymer. As degree of oligomerization increased, the relative intensity of the CT emission compared to LE emission of Me2Si-spaced oligomers displayed prominent enhancement. When compared with Me2Si-spaced copolymers with different degrees of polymerization (DP = 14 and DP = 30), this tendency reached a plateau rather than increased proportionally. On the other hand, albeit the bulky isopropyl group introduced on the silicon atom, iPr2Si-spaced monomer and dimer showed similar photophysical behaviors to those of Me2Si-spaced oligomers and copolymers. However, iPr2Si-spaced trimer and tetramer exhibited charge-transfer absorption, which is different from the intrinsic absorption of the donor and acceptor chromophores. Furthermore, tetramer showed essentially same emission from charge-transfer complex as that of iPr2Si-spaced copolymers. The charge-transfer complex emission is attributed to the strong electronic interaction between the donor and acceptor. The change of local conformation triggered by substitution of bulky isopropyl group on silicon atom and the extension of molecular structure resulted in this variation. These results suggest that the electronic interactions between adjacent donor and acceptor should be affected by the folding nature, which could be tuned by not only the steric effect of the substituents on the silicon atoms but also the extending molecular structures. In addition, the differences in the small energetic barriers for each of the conformational states may be amplified by extending the distance of the folding structure, thus resulting in a more stable conformation.
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Yeh, Cheng Yang, and 葉政洋. "Synthesis and Optoelectronic Properties of Alternative Copolymer Poly(3-hexylthiophene)-alt-Polythiophene and Random Copolymer Poly(3-hexylthiophene)-ram-Polythiophene." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31240488834769161796.
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碩士國立中正大學
化學工程研究所
99
We synthesize the alternative copolymer P3HT-alt-PT by Suzuki coupling reaction and random copolymer P3HT-ram-PT by Modified Grignard Metathesis(GRIM), comparing the advantages and the disadvantage of these two polymers, and finally we use some equipment to identify their characterization. LC/MS, 1H-NMR and FTIR can show the structure; TGA can show the temperature of decompose Td; DSC can show the glass transition temperature Tg and the melting point Tm; UV-Vis can show the absorption wavelength range of the visible light; PL can show the wavelength range of the fluorescence emitting; CV can show the HOMO, LUMO and band gap. Finally, these two polymers are used as the semi-conducting layer for the solar cell, and then we use the Oriel® Sol3A TM Class AAA Solar Simulators to identify the efficiency and the other relative characterization, expecting that they can be applied for the solar cell well. Key words: Suzuki, Grignard, efficiency, solar cell
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Liao, Wei-Chih, and 廖偉智. "The Role of Oligomethylene Linkage on the Photophysics of Alternating Dialkylsilylene-Spaced Donor-Acceptor Copolymers." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/54247370326454421912.
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碩士國立臺灣大學
化學研究所
100
Alternating dialkylsilylene-spaced donor-acceptor copolymers with two substituents (methyl vs isopropyl) on silicon and different oligomethylene linkages, piperazinyl, ethylene, tetramethylene, and 2,2-dimethylpropylene, have been designed and synthesized by Rh-catalyzed hydrosilylations. The donors were selected to be the oligomethylene-connecting bis-aminostyrene moieties, and the acceptors were chosen as the stilbene chromophores with dialkylsilyl substituents at both ends. Thorpe-Ingold effect is introduced by changing the size of the substituents (methyl vs isopropyl) on silicon. Totally different photophysical properties of SiMe2-spaced (methyl substituents on silicon) copolymers from those of SiiPr2-spaced (isopropyl substituents on silicon) copolymers were observed. Furthermore, different oligomethylene linkages provide different behaviors of rotations of sigma-bonds. Thus, different polymer folding natures would be exhibited in those polymers with similar degrees of polymerization. The photophysical behaviors in SiMe2- and SiiPr2-spaced copolymers (within a range of degrees of polymerization ca. 5~15) may be perturbed. To sum up, the photophysics of the copolymers could be affected by the synchronization of the Thorpe-Ingold effect on silicon and the polymer folding nature. Besides, it seems that polymer folding natures may be perturbed via different conformational equilibrium in various oligomethylene moieties within a range of degrees of polymerization.
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Su, Fu-Kun, and 蘇富琨. "Restraining Associations of Fluorene-Based Fluorescent Alternative and Block Copolymers by Crosslinked Network." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/r2xxrz.
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博士國立中山大學
材料科學研究所
95
Polyfluorene (PF) and its derivates as well-known fluorescent materials are promising materials in optoelectronic applications due to their high quantum yields in the solid state. Nevertheless, the easy chain inter-action in PFs to result in the unfavorable associations (aggregate and excimer) are generally considered to be detrimental to the emission efficiency in the concentrated solid state and/or at high temperatures. In the study, restraining the extent of associations is therefore by embedding fluorene-based alternative and block copolymers in crosslinked network as matrix. Firstly, alternative copolymers with fluorene connected by anthracene (or pyridine or fluorene) ring were prepared through Suzuki coupling. In this way, the steric hindrance between the o-hydrogens in the neighboring aromatic ring causes the twisting of the constructed polymer chain and the resulting twisting chain conformation keeps the polymer chains from the unfavorable inter-chain interactions and reduces the extent of the association. Secondly, the alternative fluorene-anthracene copolymer (a-PFA) from the first approach can be further chemically formulated to obtain a triblock copolymer with the central a-PFA rod block connected by two flexible poly(methyl methacrylate) (PMMA) segments. In this way, the two flexible PMMA chains serve as spatial isolator to keep the central PFA rod from approaching each other and a reduced extent of association is expected for this block polymer of b-PMMA-PFA. Thirdly, all the alternative and block copolymers cited above were immersed in the curable liquid methyl metharcylate (MMA)/ditrimethylolproanetetracrylate (DTTPT) monomer mixtures and photo-irradiated to obtain composites with the fluorescent polymers immersed in the cured crosslinked network. The chain morphology and thus the degree of associations will be successfully frozen by the immobilized crosslinked network. For systems before and after photo-irradiation, the degree of aggregation was evaluated by Uv-vis absorption, photoluminescent (PL) and PL excitation spectroscopy. Polymer concentration was found to be important factor in controlling the degree of aggregation and was discussed in this study. In addition, the cured solid composites after high-temperature annealing were studied and compared with pure PFs to evaluate the effectiveness of this crosslinking strategy in restraining the extent of aggregation. In most cases, quantum yields (ΦPLs) also were measured to evaluate the effectiveness of this strategy.
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Yang, Po-Chih, and 楊博智. "Side Chain Effects on the Optoelectronic Properties and Self Assembly Behaviors of Donor-Acceptor Alternating Conducting Copolymers." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/19076894618680046882.
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碩士國立臺灣大學
材料科學與工程學研究所
104
Donor-acceptor alternating conducting copolymers are potential materials for low cost flexible electronics such as transistors, solar cells, etc. These kinds of polymers are usually rigid and difficult to process. Through side chain engineering, we can not only tune the conformation but also optical bandgap and self assembly behavior of the copolymers. From Stille coupling reactions, we synthesized four series of donor-acceptor alternating conducting copolymers. They are basis on donor of terthiophene (3T) and acceptor of thieno[3,4-c]pyrrole-4,6-dione (TPD) by varying position, type, and length of side chain. They are named P3T(RiN)TPD(R), P3T(RiN)TPD(E), P3T(RoN)TPD(R), and P3T(RoN)TPD(E), where R is alkyl side chain and E is oligoether side chain, i represents the two R located on 3,3” position of 3T, o represents the two R located on 4,4” position of 3T, and N is the length of R. The bandgap of each copolymer is studied by the UV-Vis spectroscopy and cyclic voltammetry. The self assembly behaviors of copolymers are studied by grazing incident wide angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM). It is noteworthy that the donor-acceptor conducting copolymer with Ro chemical structure performs lamellar structure. In contrast, the copolymer with Ri exhibits hexagonal cylinder structure and lower bandgap. Ro chemical structure has a more planar 3T building block structure as compared with Ri and thus provides stronger π-π interaction between the macromolecular chains, which results in easier production of continuous stacking and forming of laminates. Meanwhile, for the copolymer with Ri chemical structure, the stacking with short-range order forms macromolecular bundles with the aid of the side chain, afterwards long-range order hexagonal cylinder structure appeared due to the self assembly of macromolecular bundles with close packing. The macromolecular bundles have the effects of extending the length of the main chain, therefore increasing the effective conjugating length and obtaining a lower bandgap. According to the results of GIWAXS, the effect of phase separation leads to a higher degree of ordering in diffraction peak (√21) of hexagonal cylinder structure. This is mainly due to the advantage of replacing R with E on the TPD, which equips copolymer with amphiphilic characteristic. In solution, due to the donating effect of long alkyl side chain toward the main chain, the λmaxsol of copolymers is shifted to longer wavelength with increasing side chain length regardless the main chain structure of copolymers. In film, the extent of red shift for copolymer containing Ro structure is larger than that containing Ri structure. By tuning the side chains on the donor-acceptor alternating conducting copolymers, we can not only tune the bandgap but also observe rare case of highly ordered hexagonal cylinder structure. All of these copolymers have self assembly structure without thermal annealing, and have the potential to be applied in the fabrication of flexible electronic devices.
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Kao, Kun-chi, and 高錕琪. "Synthesis and Photovoltaic Properties of Donor-Acceptor Alternating Conjugated Copolymers Based on Different Acceptor Units and Fluorinated Benzothiadiazole." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/60819794534463714289.
Full textAbstract:
碩士國立高雄大學
化學工程及材料工程學系碩士班
102
We have sucessfully synthesized two donor-acceptor alternating conjugated polymers P1 and P2 containing benzodithiophene and benzothiadiazole derivatives as the donor and acceptor units, respectively, for the donor materials of the active layer by Stille coupling reaction. Our study was divided into three parts. The first part was to synthesize the donor materials of both types: P1 and P2. Subsequently, all synthesized optoelectronic materials were confirmed with FT-IR and NMR analyses. Molecular weights and polydispersity indices (PDI) were obtained by GPC. Optical properties were observed with UV-vis and photoiuminescence (PL) spectra. On the other hand, by the combination of band gap values from UV-vis spectroscopies with the oxidation-reduction potential values from cyclic voltammetry (CV), highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) values of both optoelectronic materials could be estimated. In addition, thermal properties of both synthesized materials were analyzed with thermogravimetric (TGA) and differential scanning calorimetry (DSC). The third part was the application of both of the synthesized materials in the active layers of polymer bulk heterojunction photovoltaic (BHJ) solar cells and the measurements of power conversion efficiency. We studied the effects of different weight ratios of the Polymer : PCBM blends and different annealing temperatures on the performance of polymer solar cells using the blend (Polymer : PCBM) as active layers. Both P1、P2 exhibits a low band gap of 1.82 eV and 1.80 eV and broad absorption band from 350 to 900 nm, which allows it to absorb more available photons from sunlight. The bulk heterojunction polymer solar cell incorporating P1 and PCBM at a blend ratio of 1:2 and annealing temperature 150℃ exhibited the highest short-circuit current density of 3.34 mA/cm2 and a power conversion efficiency of 0.59%. The bulk heterojunction polymer solar cell incorporating P2 and PCBM at a blend ratio of 1:1 and annealing temperature 175℃ exhibited the highest short-circuit current density of 3.69 mA/cm2 and a power conversion efficiency of 0.81%.
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Alnady, Mohamed Maged Saad Abdelati. "Excited State Characterization of Oligoand Polythiophene Derivatives: Tetraphenylethene-Substituted Thiophenes, Aryl-Bithiophenes and Alternating Donor-Acceptor Indigo- Cyclopentadithiophene Copolymers." Master's thesis, 2016. http://hdl.handle.net/10316/32268.
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Dissertação de Mestrado em Química apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A comprehensive investigation of the excited state properties of polythiophenes and aryl-bithiophenes has been undertaken in solution at different temperatures. The investigated polythiophenes include the tetraphenylethene-substituted -thiophene (HomoPT) and -bithiophene building blocks (coPT). In addition, and for comparison purposes, the parent poly(3-hexylthiophene), P3HT, together with the monomeric percursor tetraphenylethene-thiophene and the bromide-substituted tetraphenylethene chromophore (Br-TPE) have also been investigated. The arylbithiophenes consist in a common core of a benzene-bithiophene unit substituted with five different side groups; again and for comparison purposes the results of the corresponding oligothiophene terthiophene (α3) was used as a model compound. This includes the determination of fluorescence quantum yields, fluorescence lifetimes both in solution and in thin films at room temperature and singlet oxygen yields yields. From the obtained data, the overall set of rate constants for all the deactivation processes fluorescence, intersystem crossing, and internal conversion, were obtained; from the data, it was found that both intersystem crossing and internal conversion are important in the decay of the lowest singlet excited state of the polythiophenes and arylthiophenes in solution. An aggregation induced emission (AIE) study was also performed for both the polythiophenes and aryl-bithiophenes; in the case of the these did not display AIE in constrast with the aryl-bithiophenes where AIE is found to be present. A complementary comprehensive investigation of the excited state characteristics of an alternating donor-acceptor Indigo-[dodecyl-cyclopentadithiophene] copolymer together with the oligomeric counterpart has been undertaken aiming to rationalize its photophysical properties. The energy transfer processes between the cyclopentadithiophene (donor) moiety and indigo (acceptor) unit and/or the occurrence of fast conformational relaxation processes in the excited state of these systems was investigated. From the overall photophysical and spectroscopic data it was seen for the oligomeric model compound and indigo-[dodecyl-cyclopentaditiophene] a high degree of electronic interaction/delocalization between the indigo and dodecylcyclopentaditiophene units both in the singlet and triplet excited states.
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Sun, Hsiang-Yao, and 孫祥耀. "Synthesis and Properties of Alternating and Random Copolymers Using Triphenylamine and Its Derivative with Diketopyrrolopyrrole for Organic Solar Cells." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94842397708833119025.
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碩士國立臺灣大學
化學工程學研究所
101
In order to obtain conjugated polymers of low energy band gap we formed the conjugated main chain structure of the donor-acceptor alternately. Donor and acceptor successfully synthesized by a series of alternating copolymers and random copolymers via Suzuki coupling reaction and Stille coupling reaction. In this research, We used triphenylamine as donor because of its great hole transporting property and helical structure. Triphenylamine can increase open circuit voltage(Voc) for organic polymer solar cell. In addition, we mounted triphenyl silicon and carbazole on side chain of triphenylamine and investigated the physical properties and photovoltaic performance of all kinds of polymer. Diketopyrrolopyrrole (DPP) was chosen as a acceptor because of its characteristic: a strong electron withdrawing monomer and light harvesting covering a wide spectrum of UV-Vis absorption. Especially,the properties of DPP unit were coplanarity and a closer π-π stacking distance that would enhance the charge mobilities. The alternating donor-acceptor strategy was the frequently observed shifting of the polymer absorption profile to the long wavelength region as opposed to a true broadening across both the visible and near-infrared regions. Therefore, we expected that different contents of 3-hexylthiophene could improve the visible absorption range of alternating copolymers and to achieved full spectral absorption. In addition,we successfully synthesized a series of alternating copolymers and random copolymers which used gel permeation chromatography, thermal gravimetric analysis, differential scanning calorimetry, UV / Vis spectrophotometer, and cyclic voltammetry to analysis their properties of optical band gaps、HOMO and LUMO. As a result all kinds of copolymer applied to the production of organic polymer solar cell and investigated characteristic of organic polymer solar cell . The highest power conversion efficiency were 3.16 %, containing weigh ratio with random copolymer(TPASi15HT75DPP10) : PC71BM = 1:2 , Voc of 0.64 V, Isc of 8.29 mA/cm2, and FF of 0.59 under AM 1.5G solar simulator
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Dzeng, Yi-Chung, and 曾益中. "Unusual Substituent-Dependent Photophysical Properties of Alternating Substituted Methylene-Diethynylbenzene Copolymers: a Comparison of Methylene versus Silylene Tethers on Polymer Folding." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/62693315107904455249.
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碩士國立臺灣大學
化學研究所
103
Alternating tert-butyl- and methyl- substituted alkoxymethylene-diethynylbenzene copolymers 11 with different degree of polymerization and the corresponding dimers 15 were synthesized. The tert-butyl substituted polymers 11b show strong emissions around 350-400 due to ground state interactions between adjacent chromophores while copolymer 11a with less bulkily methyl-substituted tether exhibits emission around 400-450 nm due to through-space interactions between nonadjacent diethynylbenzene chromophores. Such substituent effect on photophysical properties was attributed to the Thorpe-Ingold effect exerted by the bulky tert-butyl group, compressing the bond angle at the methylene tether and therefore altering the overall folding behavior of the polymer chain. As the polymer chains fold in different manner, difference in intrachain chromophore-chromophore interaction modes were expected and corresponding photophysical property differences were observed. These methylene tethered polymers have photophysical properties similar to those of the related silylene-tethered copolymers 1, albeit the relative intensity in the blue light emission is significantly smaller in methylene-bridged copolymers than in silylene-linked copolymers. Comparison between these two series of polymers suggests that folding behaviors of such polymers may depend on the tetrahedral tethers (methylene versus silylene).
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Huang, Shang-Cyuan, and 黃上權. "Effect of Fluorination of Acceptor Units on the Photovoltaic Properties of Donor-Acceptor Alternating Conjugated Copolymers Based on Silicon-Containing Donor and Benzofurazan Acceptor Units." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/21718627445662864668.
Full textAbstract:
碩士國立高雄大學
化學工程及材料工程學系碩士班
103
We have sucessfully synthesized two donor-acceptor alternating conjugated polymers P1 and P2 containing dithienosilole and benzofurazan derivatives as the donor and acceptor units, respectively, for the donor materials of the active layer by Stille coupling reaction. Both of them exhibited the intramolecular donor-acceptor characteristic and displayed a panchromatic absorption ranging from 300 to 1000 nm and P1 have an ideal bandgap of 1.41 eV, and P2 is 1.38 Ev. The structure of the polymers were confirmed by FT-IR, 1H NMR, and 13C NMR. Optoelectronic properties of the polymer were investigated and observed by UV-vis, photoluminescence spectrum, and cyclic voltammogram. Finally we were application of both of the synthesized materials in the active layers of polymer bulk heterojunction photovoltaic (BHJ) solar cells and the measurements of power conversion efficiency in different weight ratios of the Polymer : PCBM blends and different annealing temperatures on the performance of polymer solar cells using the blend (Polymer : PCBM) as active layers. The bulk heterojunction polymer solar cell incorporating P1 and PCBM at a blend ratio of 1:2 and annealing temperature 125℃ exhibited the highest short-circuit current density of 3.77 mA/cm2 and a power conversion efficiency of 0.95%. The bulk heterojunction polymer solar cell incorporating P2 and PCBM at a blend ratio of 1:1 and annealing temperature 150℃ exhibited the highest short-circuit current density of 4.13 mA/cm2 and a power conversion efficiency of 1.22%.
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Wang, Jen-Fu, and 王仁甫. "PART A: Theoretical Analysis on the Geometry and Electronic Properties of Acceptors-based Poly(heteroarylene methine)sPART B: Synthesis and Characterization of New Fluorene-based Donor-acceptor-Donor Alternating Copolymers for Transistor Applications." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/23582947253974714246.
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碩士國立臺灣大學
高分子科學與工程學研究所
94
Abstract The electronic structures and electronic properties of conjugated polymers have been tuned by modifying the chemical structures in many studies for specific aims. In this study, we divide two parts to discuss: (A) theoretical analysis on the geometries and electronic properties of acceptors-based poly(heteroarylene methine)s, and (B) synthesis the fluorene-based copolymers with donor-acceptor-donor systems(1:1) and their application on the thin-film transistors. In the PART A of this study, a comprehensive understanding on the relationship between theoretical geometries and electronic properties of acceptor-based poly(heteroarylene methine)s was explored by the density functional theory (DFT) at the B3LYP level with 6-31G basis set. The optimized geometries: bond length alternation and dihedral angle were investigated and correlated with the electronic properties: HOMO, LUMO, band gap and bandwidth. The results suggested that poly(heteroarylene methine)s had smaller band gap relative to the their homopolymers, due to the coexistence of aromatic and quinoid form and the lower LUMO energy levels. The geometries of these poly(heteroarylene methine)s were significantly affected by the fused ring size, side groups, and heteroatoms. The electronic properties of HOMO, LUMO, band gap and bandwidth were significantly controlled by the dihedral angle, bond length alternation, and the acceptor strength. The smaller bond length alternation and stronger acceptor strength result in the smaller band gap. In the PART B of this study, we synthesize the fluorene-based donor-acceptor-donor copolymer for thin film transistor applications. The copolymer was synthesized through the palladium-catalyzed Suzuki coupling reaction. The optical and electrochemical properties of PFO-DTTP determined by UV-vis and CV suggest small band gaps of 1.82 and 1.67 eV, respectively, due to the strong intramolecular charge transfer. Beside, the thin film transistor device fabricated by PFO-DTTP in DCB has field-effect mobility of 1.38*10-5 cm2/(Vs) and the maximum on/off ration observed of 5.91*103, which is slightly higher than the common TFT materials of F8T2. It suggests the significance of intramolecular charge transfer on the transistor characteristics.
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Jen-Fu, Wang. "PART A: Theoretical Analysis on the Geometry and Electronic Properties of Acceptors-based Poly(heteroarylene methine)s PART B: Synthesis and Characterization of New Fluorene-based Donor-acceptor-Donor Alternating Copolymers for Transistor Applications." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2807200615182600.
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