Teses / dissertações sobre o tema "Self-Assembly of block copolymers"
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Valverde, Serrano Clara. "Self-assembly behavior in hydrophilic block copolymers". Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5416/.
Texto completo da fonteBlockcopolymere erfahren ein stetig wachsendes Interesse, was an der steigenden Anzahl an Publikationen zu diesem Thema erkennbar ist. Zahlreiche Studien zu amphiphilen Blockcopolymeren haben dabei einige grundlegende Erkenntnisse über deren chemisches und physikalisches Verhalten, vor allem über die Selbstorganisation, hervorgebracht. So können die Größe, die verschiedenen Morphologien und auch die Stabilität der gebildeten Aggregate anhand der relativen und absoluten Blocklängen, die chemischen Struktur der Blöcke, der molekularen Architektur und der Eigenschaften des verwendeten Lösungsmittel erklärt werden. Im speziellen Fall des Wassers als Lösungsmittel bist die Selbstorganisation amphiphiler Blockcopolymere durch den hydrophoben Effekt bedingt. Dieser Arbeit liegt das Interesse an der Selbstorganisation in wässrigem Medium von Blockcopolymeren des Typs A-b-B mit A als hydrophilem Block und B als Block mit variierender Hydrophilie bzw. Hydrophpobie von unlöslich bis vollständig löslich zugrunde. Durch Variation dieser Eigenschaften von Block B soll dessen Einfluss auf das Selbstorganisationsverhalten untersucht werden. Dazu wurden mit Glucose modifizierte Polybutadien-block-Poly(N-Isopropylacrylamid)-Copolymere hergestellt und deren Selbstorganisation in Wasser untersucht. Die Copolymere bilden Vesikel mit einer asymmetrischen Membran, wobei im äußeren Bereich glycolysierte Gruppen und im inneren Bereich Poly(N-Isopropylacrylamid) (PNIPAM) vorliegen. Beim Überschreiten der low critical solution temperature (LCST) kollabiert die vesikuläre Struktur unter Bildung von Mizellen mit einem hydrophoben PNIPAM-Mizellinneren und nach außen gerichteten glycolysierten Blöcken. Diese strukturelle Umwandlung ist reversibel. Die Strukturen zeigten außerdem eine temperaturabhängige Wechselwirkung mit L-Lectin-Proteinen und die Möglichkeit zur Einkapselung organischer Moleküle konnte belegt werden. Des weiteren wurden verschiedene Gruppen von Blockcopolymeren mit zwei hydrophilen Blöcken synthetisiert (double hydrophilic block copolymers – DHBC). Die Blöcke dieser Systeme waren entweder Biopolymere oder Polymerchimäre, die in wässrigen Zwei-Phasen-Trennverfahren eingesetzt werden. Polymere, die auf Dextran- und Poly(ethylenglycol)-Blöcken basieren, zeigen Aggregatbildung in wässriger Phase. Dex6500-b-PEG5500 bildet spontan Vesikel mit PEG als „weniger hydrophilem“ Bestandteil und Dextran als löslichem Block. Die Bildung dieser Vesikel zeigte keine Emfpindlichkeit gegenüber einer Veränderung der Polymerarchitektur und der Konzentration, und nur eine geringe Sensitivität gegenüber Temperaturänderungen. Veränderungen der Blocklängen dagegen beeinflussten die Selbstorganisation und führten zu unterschiedlichen Morphologien. Längere PEG-Blöcke bevorzugten dabei die Bildung eher gekrümmter Aggregate, entgegen dem Trend, der gewöhnlicherweise für amphiphile Blockcopolymere beobachtet wird. Die Verkürzung des Dextran-Blocks fördert die Ausbildung vesikulärer Strukturen, was dem Verhalten der amphiphilen Gegenspieler der DHBC-Systeme entspricht. Die funktionelle Gruppe zur Verbindung der beiden Blöcke hat zwar einen Einfluss auf die Morphologie der gebildeten Aggregate, nicht jedoch auf die eigentliche Fähigkeit der Systeme zur Selbstorganisation. Die Dex6500-b-PEG5500-Vesikel wiesen zudem eine langsame Bildungskinetik in Gegenwart von Con-A-Lectin auf. Des Weiteren waren sowohl Dex6500-b-PEG5500 als auch das quervernetzte Derivate dieses Copolymers in der Lage, Fluoreszenzfarbstoffe einzulagern. Um zu zeigen, dass wässrige Zwei-Phasen-Systeme (aqueous two phase systems – ATPS) eine belastbare Grundlage für die Untersuchung und Entwicklung selbstorganisierender DHBC-Systeme sind, wurden weitere Dextran-basierte Copolymere synthetsisiert: Dextran-b-Poly(vinylalokohol) und Detran-b-Poly(vinylpyrrolidon). In einem zweiten Teil dieser Arbeit wurde das zuvor erarbeitete Prinzip auf auf Polypeptidsysteme ausgeweitet. Dazu wurde ein Poly(N-Hydroxyethylglutamin)-block-Poly(ethylenglycol)-Copolymer hergestellt. Dieses Copolymer, dessen emulgierenden Eigenschaften bereits bekannt waren, wies unmittelbar nach Lösung des Feststoffes in Wasser Vesikelbildung auf. In einem dritten Teil der Studie wurden thermoresponsive Copolymere hergestellt und untersucht: Dextran-b-PNIPAMm. Unterhalb der LCST konnte die Bildung von Aggregaten nachgewiesen werden, deren Struktur nicht zweifelsfrei entschlüsselt werden konnte, wobei jedoch zahlreiche Hinweise auf eine vesikuläre Struktur hindeuten. Oberhalb der LCST wurde durch die Kollabierung der PNIPAM-Ketten die Bildung stabiler Strukturen mit Radien von mehreren hundert Nanometern induziert, deren weitere Entwicklung durch eine weitere Temperaturerhöhung gefördert werden konnte. Durch Rückkühlung in den Temperaturebereich unterhalb der LCST konnten die zuvor beobachteten Aggregate reversibel zurückgebildet werden. Das Selbstorganisationsverhalten von DHBC, unabhängig vom Einfluss des pH-Werts, der Ionenstärke oder der Temperatur are bisher nur in sehr geringem Umfang Gegenstand wissenschaftlicher Veröffentlichungen. Diese Arbeit stellt damit den ersten umfassenden Beitrag zur systematischen Erarbeitung dieses Phänomens dar. Es konnten dabei zwei Ursachen für die beobachteten Selbstorganisationseffekte bestimmt werden: die Inkompatibilität der beiden Polymerblöcke (enthalpischer Effekt) und der Unterschied in deren Löslichkeit (enthalpische und entropische Effekte). Der entropische Beitrag zur positiven Gibbs’schen Freien Mischungsenergie wird dem selben Verlust konformativer Entropie zugeordnet, der auch für den hydrophoben Effekt verantwortlich ist, allerdings angetrieben durch einen Wettbewerb der beiden Polymerblöcke um das Wasser. In diesem Sinne kann man das beobachtete Phänomen als „hydrophilen Effekt“ bezeichnen.
Cheng, Li-Chen Ph D. Massachusetts Institute of Technology. "Templated self-assembly of novel block copolymers". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122156.
Texto completo da fonteCataloged from PDF version of thesis.
Includes bibliographical references.
Self-assembly of block copolymers (BCPs) is emerging as a promising route for numerous technological applications to fabricate a variety of nanoscopic structures. The resulting feature sizes range from a few to several hundred nanometers, and are readily tunable by varying the molecular weights of block copolymers. Directed self-assembly of block copolymer is an effective way to pattern periodic arrays of features with long-range order, to generate complex patterns, and to multiplicatively increase the pattern density and resolution that are far beyond the limit of conventional lithography. Despite of the significant progress in the area of directed self-assembly in recent years, critical research problems regarding the dimension scalability toward sub-10-nm regime and large feature sizes on hundreds of nanometers scale as well as the capability of generating complex device-oriented patterns remain challenging. In this thesis, BCP systems, including high-v BCPs that are capable of self-assembling into extreme small and large feature sizes as well as those with more complex block architectures, are identified and studied in order to understand how those materials may be processed and directed selfassembly to bridge the patterning size spectrum between nano- and micro-fabrication. Another focus is placed on the scientific exploration of directed self-assembly of triblock terpolymers and the investigation on the mechanisms that regulate the scaling and geometry of self-assembled patterns. A comprehensive understanding about self-assembly of BCP thin films will enable developing device-oriented geometries, manipulating BCPs phase behavior, and incorporating new functional materials for a wider range of applications. In the meanwhile, optimizing the processing condition of self-assembly of various BCPs is essential to confirm viability of the directed self-assembly of block copolymers process in manufacturing.
by Li-Chen Cheng.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering
Mohd, Yusoff Siti Fairus. "Crystallization-driven self-assembly of polyferrocenylsilane-based block copolymers". Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546192.
Texto completo da fonteJung, Yeon Sik. "Templated self-assembly of siloxane block copolymers for nanofabrication". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52791.
Texto completo da fonteThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references.
Monolayer patterns of block copolymer (BCP) microdomains have been pursued for applications in below sub-30 nm nanolithography. BCP selfassembly processing is scalable and low cost, and is well-suited for integration with existing semiconductor fabrication techniques. The two critical issues are how to obtain reliable long-range ordering of features with minimum defect densities and how to successfully transfer the patterns into other functional materials. Exceptionally well-ordered and robust nanoscale patterns can be made from poly(styrene-b-dimethylsiloxane) (PS-PDMS) BCPs, which have a very large Flory-Huggins interaction parameter between the blocks compared to other commonly used BCPs. Cylinder- or sphere-forming BCP films were spincoated over silicon substrates patterned with shallow steps using optical lithography or nanoscale posts made by electron-beam lithography, and solvent-annealed to induce ordering. This generates patterns with a correlation length of at least several micrometers. The annealed film was treated with plasma to obtain oxidized PDMS patterns with a lateral dimension of 14 - 18 nm. These can be used as an etch mask or an easily removable template for patterning functional materials. Solvent vapor treatments can tune the pattern dimension and morphology. Different degrees of solvent uptake in BCP films during solvent-annealing can manipulate the interfacial interaction between the two blocks, and a mixed solvent vapor can change the effective volume fraction of each block. The self-assembled patterns can be transferred into various kinds of functional materials.
(cont.) For example, arrays of parallel lines were used as a mask to pattern poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) conducting polymer thin films. The resulting PEDOT:PSS nanowire array was used as an chemiresistive-type ethanol-sensing device. Metallic films such as Ti, Pt, Ta, W, and magnetic Co and Ni were structured using a pattern-reversal process. Coercivity enhancements were observed for the fabricated ferromagnetic nanostructures such as wires, rings, and antidots. These functional nanostructures can be utilized for a variety of devices such as high-density and high performance sensor or memory devices.
by Yeon Sik Jung.
Ph.D.
Cowie, Lauren. "The synthesis and self-assembly of MPC block copolymers". Thesis, Durham University, 2013. http://etheses.dur.ac.uk/7341/.
Texto completo da fonteBERTANI, DANIELA. "Synthesis and self-assembly of biocompatible amphiphilic block copolymers". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/199109.
Texto completo da fonteDrug delivery is a trending topic in current research due to the need to improve therapeutic efficiency and selectivity. Polymeric encapsulants for drugs are a promising strategy to prolong circulation times, enhance hydrophobic drug transport through the blood stream, and modulate drug release over time. In this field, amphiphilic block copolymers’ (BCs) spontaneous organization in compartimentalized nanoparticles (NPs) in water is a powerful tool for the fabrication of drug delivery systems. In this Doctoral thesis, the controlled synthesis and self-assembly (S-A) of a series of amphiphilic BCs containing biocompatible, stealthy hydrophilic blocks were investigated. Controlled polymerization techniques were employed to prepare copolymers with narrow molecular weight distributions. In Chapter 3, a complete picture of the previously unreported S-A behaviour of PS-b-PDMA in water from DMF is drawn. A comprehensive sample set spanning molecular weights from 10 kDa to 57 kDa and hydrophilic volume fractions fPDMA from 0.06 to 0.75 was prepared by sequential RAFT, and NPs were characterized by DLS, TEM, CEM, CET, SEM, and AFM. A morphology map is proposed, where predominant morphologies were correlated with BC chemical characteristics. In particular, stable hollow particles with diameters up to several microns when fPDMA drops below 0.15 are formed. Micron-large porous particles exhibiting a sponge phase which can withstand lyophilisation were observed. In Chapter 4, a series of biocompatible and biodegradable PEO-b-PLA BCs were synthesized by controlled ROP of lactide catalyzed by non-toxic DBU. The research focus was on the effect of the non-selective solvent on S-A: NPs obtained from ACT, DX, THF, DMF were analyzed by DLS, CEM and CET. Both size and PDI increased in the order ACT < DX < THF ~ DMF. NPs were classified into three clusters, labeled micelles (small size, low PDI), polymersomes (medium size, medium-low PDI) and large compound micelles (large size, large PDI). While ACT and DX yielded mostly micelles, THF allowed to access a much broader morphological space. Finally, DMF favoured second-order aggregation phenomena. In Chapter 5, controlled synthesis, chain-end functionalization and di- and triblock formation of biocompatible PEtOx-based polymers by a combination of ROP and RAFT techniques were evaluated. Biocompatible PEtOx25 blocks were successfully synthesized by CROP of 2-ethyl-2-oxazoline with good control. PEtOx25 was used as a macroCTA for the sequential polymerization of a Sty and tBA to yield a PEtOx25-b-PS50-b-PtBA25 triblock copolymer. Preliminary results on S-A in ethanol as a selective solvent for both PEtOx and PtBA, but not for PS, are presented. In Chapter 6, the morphogenic effect of ACT, DX and DMF on PS-b-PDMA and PEO-b-PLA S-A was studied using molecular rotor AzeNaph-1 as a local viscosity probe for the in situ monitoring of BC aggregation. Evolution of viscosity as a function of water content in PS-b-PDMA was similar both in DMF and DX: upon the addition of H2O, PS chains rapidly collapsed in NP cores, which were largely glassy. Consistently, DLS shows little variation on particle size between the two solvents. PEO113-b-PLAx also formed glassy domains in DMF/H2O, but not in ACT or DX. Contrarily, local core viscosity was much lower in ACT and DX than in DMF over the whole H2O fraction range, and was time-dependent. This increased chain mobility promoted the differentiation of NP formation. Finally, in Chapter 7, polymerization-induced S-A of glycopolymer-based amphiphilic BCs was investigated. Three PAGA samples with DP = 25, 50 and 75 were polymerized in H2O/methanol mixture by RAFT, with remarkable control. Optimization of reaction conditions allowed the use of PAGA25 and PAGA50 as stabilizers and macroCTAs for chain-extension with n-butylacrylate (BA) in methanol/H2O environment. Control on the polymerization was poor, but stable and monodisperse spherical NPs were obtained.
Gomes, Correia Cindy. "Directed self-assembly strategies for orientation-controlled block copolymers for advanced lithography". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0393.
Texto completo da fonteThe objective of our work was to highlight the potential of the high-χ PDMSB-b-PS BCP for advanced nanolithography applications. For this purpose, we have demonstrated the ability of our system to self-assemble into well-defined nanostructures in bulk and we have performed the self-assembly of cylinder- and gyroid-forming PDMSB-b-PS BCPs in thin film using industrially-friendly processes (Chapter 2). With the aim of controlling the out-of-plane orientation of lamellar-forming PDMSB-b-PS BCPs in thin film, we have proposed an innovative approach relying on the use of crosslinkable neutral TC layers. The versatility of this approach was demonstrated using BCPs having different macromolecular characteristics and extended to the formation of multi-layer stacks through an iterative self-assembly process (Chapter 3). Taking advantage of the crosslinking ability of our TC material, we have outlined the patterning ability of the TCs using photosensitive crosslinking agents. The patterning of neutral TCs above the lamellar-forming PDMSB-b-PS BCPs further allowed a control of the orientation of the PDMSB-b-PS domains in specific areas of the film (Chapter 4)
Evangelio, Araujo Laura. "Directed self-assembly of block copolymers on chemically nanopatterned surfaces". Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/406119.
Texto completo da fonteThe thesis entitled “Directed self-assembly of block copolymers on chemically nano-patterned surfaces”, aboard the challenge of the development, implementation and characterization of a chemical epitaxy process to direct self-assemble block copolymers. The development of this nanofabrication method contributes to the next generation of nanoelectronic devices and circuits. Firstly, the main aspects of directed self-assembly of block copolymers and its role and status in the future of nanoelectronics is presented, and compared with other powerful technologies. Then, a general overview about the physics and chemistry involved in block copolymer thin films is presented, in order to understand and determine the interactions taking place during the DSA process. The main part of the thesis is focused on the study, development and implementation of a chemical epitaxy approach to guide the self-assembly of block copolymers. Apart from the process development, the mechanisms which drive the block copolymer alignment are characterized and simulated into a DSA model. Moreover, the process transfer to a more industrial pilot line is presented. The implementation of the chemical epitaxy process is addressed not only with commercial block copolymers, but also with new polymer systems which allow getting sub- 10 nm resolution. For these systems, a new guiding method is presented based on the combination of a chemical and graphoepitaxy approach. To better understand the DSA process, dedicated metrology methods are also studied. In particular, by using high-energy X-ray techniques it is possible to describe the main characteristics of the chemical guiding patterns. On the other hand, the nanomechanical properties of block copolymer domains are studied by using the peak force tapping mode in atomic force microscopy. A reliable method to pattern transfer the block copolymer features into the substrate is showed. It is based on infiltrating one block copolymer domain and enhancing thus, its resistivity to plasma etching. Finally, as a final application, a novel fabrication process of a nanowire mechanical resonator by means of DSA and infiltration is presented.
Weiß, Jan. "Synthesis and self-assembly of multiple thermoresponsive amphiphilic block copolymers". Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5336/.
Texto completo da fonteDie Selbstorganisation von mehrfach thermisch schaltbaren Blockcopolymeren in verdünnter wässriger Lösung wurde mittels Trübungsphotometer, dynamischer Lichtstreuung, TEM Messungen, NMR sowie Fluoreszenzspektroskopie untersucht. Die schrittweise Überführung eines hydrophilen in ein hydrophobes Blockcopolymer beinhaltet ein oder mehr amphiphile Zwischenstufen mit einstellbarem hydrophilen zu lipophilen Anteil (HLB). Dies führt dazu, dass die Selbstorganisation solcher Polymere in Lösung nicht nur einem Alles-oder-nichts-Prinzip folgt sondern ein mehrstufiges Aggregationsverhalten beobachtet wird. Die Synthese von doppelt thermisch schaltbaren Diblockcopolymeren und dreifach thermisch schaltbaren Triblockcopolymeren wurde durch sequenzielle RAFT Polymerisation realisiert. Dazu wurden zweifach TMS-markierte RAFT Agentien verwendet, welche die Bestimmung der molaren Masse sowie der verbliebenen Endgruppenfunktionalität direkt aus einem Protonen NMR Spektrum erlauben. Mit diesen RAFT Agentien wurde zunächst eine Serie von doppelt thermisch schaltbaren Diblockcopolymeren aus Poly(N-n-propylacrylamid)-b-Poly(N-ethylacrylamid), welche sich lediglich durch die relativen Blocklängen unterscheiden, hergestellt. In Abhängigkeit von der relativen Blocklänge wurde ein unterschiedliches Aggregationsverhalten der Diblockcopolymere in verdünnter wässriger Lösung beobachtet. Des Weiteren wirken die komplementär TMS-markierten Endgruppen als NMR-Sonden während der schrittweisen Aggregation dieser Polymere. Reversible, temperaturabhängige Peakaufspaltung der TMS-Signale in der NMR Spektroskopie spricht für eine Aggregation in gemischte stern-/blumenartige Mizellen, in denen ein Teil der hydrophoben Endgruppen in den hyrophoben Kern zurückfaltet. Obendrein wurden dreifach thermisch schaltbare Triblockcopolymere aus Poly(N-n-propylacrylamid) (A), Poly(methoxydiethylen glycol acrylat) (B) und Poly(N-ethylacrylamid) (C) in allen möglichen Blocksequenzen (ABC, BAC, ACB) durch schrittweisen Aufbau mittels RAFT Polymerisation erhalten. Das Aggregationsverhalten dieser Polymere in verdünnter wässriger Lösung war relativ komplex und hing stark von der Position der einzelnen Blöcke in den Triblockcopolymeren ab. Besonders die Position des Blocks mit der niedrigsten LCST (A) war ausschlaggebend für die resultierenden Aggregate. So wurde oberhalb der ersten Phasenübergangstemperatur nur Aggregation der Triblockcopolymere beobachtet, wenn der A Block an einem der beiden Enden der Polymere lokalisiert war. Wurde der A Block hingegen in der Mitte der Polymere positioniert, entstanden unimere Mizellen zwischen der ersten und zweiten Phasenübergangstemperatur, welche erst aggregierten, nachdem der zweite Block (B) seinen Phasenübergang durchlief. Die Transportereigenschaften dieser Triblockcopolymere wurden mittels Fluoreszenzspektroskopie getestet. Dazu wurde die Einlagerung eines hydrophoben, solvatochromen Fluoreszenzfarbstoffes, Nilrot, in Abhängigkeit der Temperatur untersucht. Im Gegensatz zu den Polymeren mit der Blocksequenz ABC oder ACB, zeigten die Polymere mit der Sequenz BAC eine verminderte Aufnahmefähigkeit des hydrophoben Farbstoffes oberhalb des ersten Phasenübergangs, was auf die fehlende Aggregation und die damit verbundenen relativ kleinen hydrophoben Domänen der unimolekularen Mizellen zwischen der ersten und zweiten Phasenübergangstemperatur zurückzuführen ist. Aufgrund des zunehmenden Verlustes von funktionellen Endgruppen während der RAFT Synthese von Triblockcopolymeren wurde ein neuartiges Konzept zur Einschrittsynthese von mehrfach schaltbaren Blockcopolymeren entwickelt. Dieses erlaubt die Synthese von mehrfach schaltbaren Diblock- und Triblockcopoylmeren in einem einzelnen Reaktionsschritt. Die Copolymeriation von verschiedenen N-substituierten Maleimiden mit einem thermisch schaltbaren Styrolderivat (4-Vinylbenzylmethoxytetrakis(oxyethylene) ether) ergab alternierende Copolymere mit variabler LCST. Die Verwendung eines Überschusses dieses styrolbasierten Monomers erlaubt ferner die Synthese von Gradientenblockcopolymeren in einem einzelnen Polymerisationsschritt.
Parras, Petros. "Self-assembly and dynamics in block copolymers with hierarchical order". Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493799.
Texto completo da fonteBurd, Caroline Glenn. "Supramolecular block and random copolymers in multifunctional assemblies". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24627.
Texto completo da fonteCommittee Chair: Marcus Weck; Committee Member: Bunz, Uwe; Committee Member: Collard, David; Committee Member: Jones, Christopher; Committee Member: Payne, Christine
Farias, Mancilla Bárbara Isabel. "Asymmetric copolymers : neither block nor random". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30288.
Texto completo da fonteBlock copolymers are made from polymer chains of different chemical composition that are covalently joined via their respective end groups. On the other hand, there are statistical copolymers whose monomers are randomly copolymerized together. Between these structures exist asymmetric copolymers, which are defined as a distribution of monomers within the chain which is neither completely segregated as for a block copolymer nor statistically distributed in a manner that is independent of the position along the chain as in the case of statistical copolymers. Based on the latter, the properties of asymmetric copolymers are expected to combine characteristics of block and statistical structures. In this investigation, acrylic acid-(n-butyl acrylate) (AA-n-BA) copolymers and dimethylacrylamide-N-isopropylacrylamide (DMA-NIPAM) copolymers, with targeted molecular weights of 10 kg mol-1 and 20 kg mol-1, were obtained by RAFT polymerization using forced and stepwise synthesis. Both copolymer systems are stimuli-responsive polymers: macromolecules which undergo phase transitions when they experience subtle changes in the environmental conditions. P(AA-n-BA) copolymers are pH-responsive and P(DMA-NIPAM) copolymers are thermosensitive. The composition of the copolymers was always the same (50% AA or 50% NIPAM), but the distribution of the monomer units within the chain was different. Block, statistical, gradient, asymmetric diblock and triblock structures were obtained with the aim to compare their physical and self-assembly properties. The macromolecular characteristics of copolymers were obtained by nuclear magnetic resonance spectroscopy (1H NMR) and size exclusion chromatography (SEC). P(AA-nBA) copolymers in solution at different pH were studied by dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron scattering (SANS) and it was possible to demonstrate the changes in size and self-assembly behavior as a function of pH of the copolymers solutions. The results showed that the P(AA-nBA) asymmetric copolymers form aggregates of different morphology depending on the pH, for example vesicles at pH 4 or micelles and worms at pH 5. On the other hand, the morphology of block copolymers with the same composition, is not influenced by changes in pH. P(DMA-NIPAM) copolymers in solutions were analyzed by DLS, SANS and 1H NMR as a function of temperature. The evolution of hydrodynamic size as a function of temperature could be followed by DLS and the temperature-induced micellization was analyzed by SANS whereas by 1H NMR, the temperature-induced collapse and resulting loss of mobility of the polymer chains could be followed at a molecular level. Interesting results were obtained, since low molar mass block copolymers (Mn = 10 kg mol-1) displayed similar behavior to the corresponding to high molar mass gradient copolymer (Mn = 20 kg mol-1). This phenomenon was observed by SANS and 1H NMR, and it was attributed to the short length scale of the block copolymer, in which the chain is short enough that a significant fraction of the NIPAM units in the block copolymer are strongly affected by the DMA of the adjoining block, leading to a gradual change in the effective composition of the polymer as a function of chain length
Permyakova, N. M., T. B. Zheltonozhskaya, D. O. Klymchuk e M. Ya Poliyan. "Template Synthesis and Micellization of Block Copolymers with Interacting Blocks". Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35608.
Texto completo da fonteAhmed, Rumman. "Novel hierarchical structures form PFS block copolymers using ionic self-assembly". Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529854.
Texto completo da fonteShnayderman, Marianna 1982. "Characterization of nano-arrays fabricated via self-assembly of block copolymers". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32725.
Texto completo da fonteIncludes bibliographical references (leaves 28-29).
This research focused on methods for regulating arrangement of self-assembled block copolymers by understanding fabrication conditions and their effects on the polymers on flat and patterned substrates. Block copolymer self-assembly is a simple and low cost process for creating lithographic masks with features under 100nm in dimension. These patterns can be transferred to more permanent materials for applications in electronics, magnetic devices, as well as sensors and filters. Polystyrene-poly(ferrocenyldimethylsilane) block copolymer thin films were characterized in terms of their spin curves, PSF spherical domain cross sectional area distributions, and correlation distances. Optimal fabrication conditions were selected from studying polymer behavior on flat substrates and then used for templated substrate studies. Substrates that were templated with grooves produced quantized numbers of rows of spherical domains ranging from 4 to 7. Behavior in these grooves was characterized in terms of groove width constraints, cross sectional domain area distributions, and row ordering. For all templated arrays, the lengths of ordered regions were more than 2 fold higher than the diameters of ordered regions of arrays on flat substrates. The characterization accomplished in this work will be used to compare block copolymers with similar volume fractions of the blocks that allow sphere microdomain formation but of different molecular weights. The ultimate goals are to establish how the molecular weight of this block copolymer affects its self assembly on templated and on flat substrates and to use this factor as well as fabrication conditions and template geometries to engineer arrays with desirable properties.
by Marianna Shnayderman.
S.B.
Stokes, Kristoffer Keith. "Synthesis and solution state self-assembly of linear-dendritic block copolymers". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39583.
Texto completo da fonteVita.
Includes bibliographical references.
Linear-dendritic block copolymers consisting of a poly(styrene) linear block and poly(amidoamine) dendrimer block were synthesized and examined for their ability to self-assemble in both aqueous environments and organic/aqueous mixtures. These polymers were shown to assemble into vesicle structures under a variety of conditions. Furthermore, size measurements of the dendritic portion were taken by means of Langmuir-Blodgett isotherms, demonstrating both the steric area, as well as the electrostatic area occupied by the dendrimer in a monolayer. Further studies into the rapid synthesis of such systems were also undertaken, with a particular interest in use of the so-called "click" reaction to be used as a facile means toward block copolymer synthesis.
by Kristoffer Keith Stokes.
Ph.D.
Lam, Christopher N. (Christopher Nguyen). "Interactions governing the self-assembly of globular protein-polymer block copolymers". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104208.
Texto completo da fonteCataloged from PDF version of thesis.
Includes bibliographical references.
Engineering enzymes and other proteins into biocatalysts or bioelectronic devices has the potential to lead to a new generation of energy-generating and energy conversion technologies. Controlling the hierarchical structure of protein materials from the nanoscale single molecule level up to the microscale material morphology is critical to improving their function. Lithographic patterning methods such as electron beam lithography, dip-pen nanolithography, and nanograftin allow proteins to be patterned with nanoscale resolution, but parallelization to increase throughput remains a significant challenge. While templated self-assembly enables patterning in three dimensions, maximizing protein loading and controlling orientation are challenges that remain to be addressed. Self-assembly provides a low-cost method to nanopattern proteins for biofunctional devices with high operational efficiency through control over three-dimensional spatial arrangement and orientation. Complementary experimental techniques were used to investigate the phase behaviors of globular protein-polymer block copolymers and provide insight into the relevant physics and thermodynamics governing their self-assembly. In particular, methodical permutations were made to the protein block to understand the relationship between protein interactions and protein-polymer block copolymer selfassembly. Order-disorder and order-order transitions were demonstrated for the first time within a rich window of phase space of hexagonal, lamellar, perforated lamellar, and micellar phases that were dependent on coil fraction. Protein-polymer net repulsive interactions were discovered to be important for self-assembly. The type of nanostructures formed at a given coil fraction are different between globular-coil and coil-coil systems due to the anisotropy between protein and coil shape and interactions and minor differences in solvent selectivity. A set of structurally homologous proteins in which the chemical composition and surface interaction potential were varied globally throughout the entire sequence and locally through single point mutations demonstrated highly similar phase behavior, revealing that coarse-grained properties such as the protein shape, size, solubility, surface charge, and virial coefficient can capture the general shape of the phase diagram in nonselective solvents. Engineering greater changes in protein electrostatic interactions and virial coefficient demonstrated that the electrostatic environment of proteins may be designed to tune the morphologies of protein-polymer blok copolymers, both enhancing and suppressing formation of nanostructures through attractive and repulsive interactions, respectively. A combination of small-angle neutron scattering experiments, theory, and coarse-grained modeling and simulation was used to elucidate the shape of protein-polymer block copolymers in dilute solution and quantify their interactions. Modeling protein-polymer interactions using repulsive Weeks-Chandler- Andersen potentials showed that the polymer exists as a relatively unperturbed coil extended away from the protein. The coarse-grained representation additionally provides a simple way to model the conformation of protein-polymer conjugates with strong interactions that result in the polymer wrapping around the protein in a shroud-like configuration.
by Christopher N. Lam.
Ph. D.
Boott, Charlotte E. "Advances in crystallization-driven self-assembly of polyferrocenylsilane-based block copolymers". Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702892.
Texto completo da fonteDo, Hyung Wan. "Computation by block copolymer self-assembly". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/117840.
Texto completo da fonteThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
Unconventional computation is a paradigm of computation that uses novel information tokens from natural systems to perform information processing. Using the complexity of physical systems, unconventional computing systems can efficiently solve problems that are difficult to solve classically. In this thesis, we use block copolymer self-assembly, a well-studied phenomenon in polymer science, to develop a new approach to computing by applying directed self-assembly to implement Ising-model-based computing systems in materials. In the first part of the thesis, we investigate directed self-assembly of block copolymer thin films within templates of different polygonal shapes. We define a two-state system based on the two degenerate alignment orientations of the ladder-shaped block copolymer structures formed inside square confinements, and study properties of the two-state system. In the second part of the thesis, we demonstrate an Ising lattice setup for directed self-assembly of block copolymers defined on two-dimensional arrays of posts. We develop an Ising-model-based simulation method that can perform block copolymer pattern prediction and template design. Finally, we design simple Boolean logic gates as a proof-of-concept demonstration of computation.
by Hyung Wan Do.
Ph. D.
Pinto, Gómez Christian. "Directed self-assembly of block copolymers for the fabrication of nanomechanical structures". Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/671972.
Texto completo da fonteEl principal objetivo de esta tesis, titulada "Autoensamblaje dirigido de copolímeros de bloque para la fabricación de estructuras nanomecánicas", es demostrar la posibilidad de fabricar estructuras nanomecánicas funcionales mediante el autoensamblaje dirigido (DSA) de copolímeros de bloque (BCPs) como técnica de nanoestructuración. El DSA es una técnica de nanolitografía bottom-up basada en la capacidad que tienen los BCPs de segregarse en dominios de escala micro/nanométrica. Gracias a su alta resolución, alto rendimiento y bajo coste, esta técnica ha sido muy estudiada por la industria de semiconductores para nanoelectrónica, pero también ha sido aplicada en otros campos que requieren de una alta densidad de elementos a escala nanométrica. En esta tesis presentamos un proceso novedoso basado en DSA que demuestra ser apto para la fabricación de sistemas nanomecánicos. Demostramos la fabricación de membranas de silicio suspendidas ancladas por matrices de gran número de nanohilos de silicio empleando la grafoepitaxia de poliestireno-b-polimetilmetacrilato (PS-b-PMMA), uno de los BCP más extendidos. Los dispositivos obtenidos pueden desarrollarse para construir sensores de masa de alta sensibilidad basados en resonadores nanomecánicos.
The main goal of this dissertation, entitled "irected self-assembly of block copolymers for the fabrication of nanomechanical structures", is to demonstrate the possibility of fabricating nanomechanical functional structures by employing the directed self-assembly (DSA) of block copolymers (BCPs) as a nanopatterning tool. DSA is a bottom-up nanolithography technique based on the ability of BCPs to segregate into domains at the micro/nanoscale, and it has attracted high interest due to its inherent simplicity, high throughput, low cost and potential for sub-10 nm resolution. Thanks to these characteristics, the technique has been heavily studied by the semiconductor industry for nanoelectronics, and also applied to alternate fields that might require from the definition of high-density nanoscale features. In this thesis we present a novel fabrication route based on DSA that proves to be suitable for the fabrication of nanomechanical systems. Here, we demonstrate the fabrication of suspended silicon membranes clamped by high-density arrays of silicon nanowires by using a DSA approach based on the graphoepitaxy of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA), a well-known diblock copolymer. Obtained devices can be further developed for building up high-sensitive mass sensors based on nanomechanical resonators.
Universitat Autònoma de Barcelona. Programa de Doctorat en Enginyeria Electrònica i de Telecomunicació
Chen, Senbin. "Synthesis of original block copolymers by combination of RAFT polymerization and supramolecular self-assembly". Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0034.
Texto completo da fonteThis work dealt with the preparation and the study of supramolecular block copolymers based on hydrogen-bonding between homocomplementary or heterocomplementary stickers. The synthetic strategy was based on the combination of RAFT-mediated controlled radical polymerization and supramolecular chemistry. In the Chapter 2, we developed a strategy relying on the design of RAFT agents bearing thymine/diaminopyridine (DAP) recognition pairs and capable to grow well-defined miktoarm star supramolecular copolymers. To further extend the scope of H-bonding RAFT agents, in the Chapter 3, we also investigated the preparation of RAFT agents functionalized with motifs exhibiting very high binding constants. The Hamilton/barbiturate couple (log(K)≈4-5) was selected to generate more stable supramolecular block copolymers. Aiming at elaborating original associating macromolecules and at simplifying the strategy of synthesis, we finally explored the preparation ABC triblock supramolecular copolymers based on PA11 oligomers (OPA11) in Chapter 4. Ligation of a relevant dithiobenzoate group on the oligomers afforded oligomeric RAFT agents that allow for the preparation of ABC triblock supramolecular copolymers, where A is semi-crystalline, B in rubbery state and C in glassy state. Studies on the incorporation of such copolymers in epoxy networks are under progress
Cheng, Jing. "Toward sub-10 nm lithographic processes: epoxy-based negative tone molecular resists and directed self-assembly (DSA) of high χ block copolymers". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49113.
Texto completo da fontePapalia, John M. "Self-ordering of spherical nanoparticles in a block copolymer system". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 192 p, 2007. http://proquest.umi.com/pqdlink?did=1251906361&Fmt=7&clientId=79356&RQT=309&VName=PQD.
Texto completo da fonteGottlieb, Steven. "High-resolution guiding patterns for the directed self-assembly of block copolymers". Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/669854.
Texto completo da fonteVerploegen, Eric Anton. "Morphology and self-assembly behavior of side chain liquid crystalline block copolymers". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44386.
Texto completo da fonteIncludes bibliographical references.
There is significant interest from both the academic and industrial communities for understanding and controlling the self-assembly behavior of complex macromolecular systems and has been an active area of research in recent years. Such systems can be designed to result in a wide range of nanoscale morphologies and greater functionality can be introduced with increasing complexity.This thesis focuses on the synthesis and characterization of a class of side chain liquid crystalline block copolymers (SCLCBCPs) that are based on a low glass transition temperature (Tg) siloxane backbone. Moieties that self-assemble into smectic liquid crystalline (LC) phases are covalently attached to the polystyrene-polyvinylmethylsiloxane (PS-PVMS) block copolymer backbone. Precise control over the functionalization of the LCs onto the functional siloxane backbone allows for unique control over the self-assembly and the resulting properties of the system. The LC content significantly affects the stability of the smectic mesophase and subsequently the interactions with the inter-material dividing surface (IMDS) with the PS domains. A strong preference for homogenous anchoring of the LC moieties relative to the IMDS is observed, and increasing the LC content intensifies the preference for this arrangement. Utilizing the effects of LC anchoring to alter the self-assembly behavior is a reoccurring theme throughout this work. Additionally, the mechanical properties of these materials can be precisely manipulated over several orders of magnitude through variations in LC content and the block copolymer backbone architecture.Several methods can be used to manipulate the morphologies of these materials once synthesized including, thermal annealing and mechanical deformation.
(cont.) Thermal annealing provides additional mobility for self-assembly often resulting in morphological rearrangements. Mechanical deformation can be used to orient the self-assembled structures relative to an applied shear flow. Additionally, the self-assembled morphologies of spin cast into thin films were investigated. The presence of the substrate has significant effects upon the orientation of the morphologies; thermal annealing and variations liquid crystal content are shown to be useful tools for achieving a wide range of thin film morphologies.
by Eric Anton Verploegen.
Ph.D.
Hales, Kelly D. "Design and characterization of self-assembled nanostructures of block copolymers in solution". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 130 p, 2009. http://proquest.umi.com/pqdweb?did=1679669801&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completo da fonteSalvatore, Stefano. "Optical metamaterials by block-copolymer self-assembly". Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/245292.
Texto completo da fonteBai, Wubin. "Block copolymer self-assembly and templating strategies". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104103.
Texto completo da fonteThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
Block copolymers microphase separate to form periodic patterns with period of a few nm and above without the need for lithographic guidance. These self-assembled nanostructures have a variety of bulk geometries (alternating lamellae, gyroids, cylinder or sphere arrays, tiling patterns, core-shell structures) depending on the molecular architecture of the polymer and the volume fraction of its blocks. And in thin films, surface interaction and commensurability effect influence the self-assembly and result in more diverse morphologies including hexagonal-packed perforated lamellae, square array of holes. The progress of self-assembly can be tracked in situ using Grazing Incidence Small Angle X-ray Scattering, and the annealed morphology can be revealed in 3D using TEM tomography. Moreover, non-bulk morphologies can be produced, the ordering of the microdomains can be improved and their locations directed using various templates and processing strategies. The blocks can themselves constitute a functional material, such as a photonic crystal, or they can be used as a mask to pattern other functional materials, functionalized directly by various chemical approaches, or used as a scaffold to assemble nanoparticles or other nanostructures. Block copolymers therefore offer tremendous flexibility in creating nanostructured materials with a range of applications in microelectronics, photovoltaics, filtration membranes and other devices.
by Wubin Bai.
Ph. D.
Birnkrant, Michael J. Li Christopher Yuren. "Combining holographic patterning and block copolymer self-assembly to fabricate hierarchical volume gratings /". Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3134.
Texto completo da fonteUpadhyaya, Lakshmeesha. "Self-assembled smart filtration membranes from block copolymers and inorganic nanoparticles". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT242/document.
Texto completo da fonteThis thesis presents a new approach to produce mix matrix membranes using block copolymers and inorganic nanoparticles having magnetic properties. The polymeric nanoparticle with different morphologies (linear, Spheres, worms, and vesicles), from poly (methacrylic acid)-b-(methyl methacrylate) diblock copolymer, were synthesized using Reversible addition−fragmentation chain transfer polymerization (RAFT) in ethanol at 70 ֠C. The inorganic counterpart, iron oxide nanoparticles were prepared using different stabilizers at various temperatures to acquire the necessary surface charge and magnetic properties. The chemistry of the particles leads to form both hydrophobic membranes using non-solvent induced phase separation as well as a hydrophilic membrane by using the simple spin coating technique with the particles from polymerization induced self-assembly. By a detailed experimental study of the membrane filtration, the influence of different parameters on the process performance has been investigated with and without magnetic field. Finally, membrane fouling has been studied using protein solution. Also, the membrane performance was examined under magnetic field revealing the successful reduction in the fouling phenomenon making them new performant membranes in the area of membrane technology
Valverde, Serrano Clara [Verfasser], e Markus [Akademischer Betreuer] Antonietti. "Self-assembly behavior in hydrophilic block copolymers / Clara Valverde Serrano. Betreuer: Markus Antonietti". Potsdam : Universitätsbibliothek der Universität Potsdam, 2011. http://d-nb.info/1023802864/34.
Texto completo da fonteChaube, Anay. "Self assembly of block copolymers : applicability in microelectronics and gains for patterned media". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45348.
Texto completo da fonteIncludes bibliographical references (leaves 88-93).
As device size decreases, conventional lithographic methods are finding it increasingly hard to keep up. Introduction of newer method such as E-beam, X-ray lithography etc. has demonstrated possibility of scaling to lower dimensions. However most of these methods are too expensive, too complex or too slow. Hence a method is required which can provide high resolutions at low cost, is easy to implement and can be integrated with current processing technologies. Block copolymer self assembly promises to do just that. An immiscible block copolymer will microphase separate into individual domains due to unfavorable mixing enthalpy. These microphase-separated blocks can have domain sizes of very low dimensions, to the order of 15-20 nms. By careful preparation, microphase-separated thin films of immiscible block copolymers can act as nanomasks for a variety of applications in electronic, optoelectronic and storage media fields. One such application is patterned media. With ever increasing areal densities, there is a limit to which the grain size within a bit can be decreased, for a conventional thin film media. Beyond a certain limit, which is dictated by the superparamagnetic effect, these grains will spontaneously reverse, resulting in undesired data loss. Patterned media has been proposed as an alternative to surpass this thermal instability criterion. In patterned media, lithographically defined nano-scale magnetic elements form single bits onto which the data is stored. Due to its unique structure in which each magnetic dots act as a single magnetic domain it can postpone the arrival of superparamagnetic effect beyond densities much higher than 10 Terabits/inch². However, very high resolutions and strict positioning control is required for its fabrication so as to attain a marketable 1Tb/inch² advantage.
(cont.) Block Copolymer self assembly holds great promise in fabrication of such devices requiring periodic, high resolution pattern generation. If issues such as long range order, pattern uniformity and placement accuracy of magnetic dots can be effectively resolved, block copolymer self assembly enabled lithography can quickly become the main stay of the multimillion dollar hard disk industry.
by Anay Chaube.
M.Eng.
Oliver, Alex Matthew. "New directions in the crystallisation-driven self-assembly of polyferrocenylsilane-containing block copolymers". Thesis, University of Bristol, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752813.
Texto completo da fonteAhn, Dae Up. "Well-Aligned 3-Dimensional Self-Assembly in Block Copolymers and Their Nanotechnological Applications". University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1196375211.
Texto completo da fonteSamant, Saumil. "Directed Self-Assembly of Block Copolymers for High Energy Density Polymer Film Capacitors". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468449545.
Texto completo da fonteKynaston, Emily L. "Functional nanomaterials from the crystallisation driven self-assembly of π-conjugated block copolymers". Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686240.
Texto completo da fonteKalva, N. "Synthesis and self-assembly studies of amphiphilic stimuli-responsive linear-dendritic block copolymers". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2016. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5885.
Texto completo da fonteTangbunsuk, Siree. "Solution self-assembly of metallopolymer-peptide conjugates and block copolymers with a crystallisable core-forming polylactide block". Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540871.
Texto completo da fonteUnderhill, Royale Suzanne. "Block copolymer self-assembly, thermodynamics, kinetics and applications". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0019/NQ54816.pdf.
Texto completo da fonteJarnagin, Nathan D. "High χ block copolymers for sub 20 nm pitch patterning: synthesis, solvent annealing, directed self assembly, and selective block removal". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50287.
Texto completo da fonteWang, Jingbo [Verfasser]. "Hierarchical ordering : self-assembly of block copolymers in active liquid crystalline matrices / Jingbo Wang". Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1030383464/34.
Texto completo da fonteTang, Tian. "Self-assembly of block copolymers and nanoparticles and their applications as environmentally responsive materials". Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515797.
Texto completo da fonteNunns, Adam. "Bulk, thin film and solution self-assembly of block copolymers containing a polyferrocenysilane metalloblock". Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680125.
Texto completo da fonteGiammaria, Tommaso Jacopo. "Self-Assembly of Cylinder-Forming Block Copolymers by Means of High-Temperature Thermal Treatments". Doctoral thesis, Università del Piemonte Orientale, 2018. http://hdl.handle.net/11579/97184.
Texto completo da fonteCeresoli, M. "SYMMETRIC BLOCK COPOLYMERS TEMPLATES FOR NANO-LITHOGRAPHIC APPLICATIONS". Doctoral thesis, Università degli Studi di Milano, 2016. http://hdl.handle.net/2434/422644.
Texto completo da fonteFedorchuk, S. V., L. Kunitskaya, T. Zheltonozhskaya, Yu Gomza e S. Nessin. "Syntheses of Silver Nanoparticles in the Matrices of Block Copolymers in Aqueous Solutions". Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34965.
Texto completo da fonteTu, Kun-Hua. "Block copolymer self-assembly : lithography, magnetic fabrication, and optimization". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113991.
Texto completo da fonteCataloged from PDF version of thesis.
Includes bibliographical references.
Block copolymer (BCP) self-assembly is attractive because it provides nanoscale long-range ordered structures in a massive quantity. The capability of generating features with size as low as 5 nm is of particular interest in semiconductor fabrication since current photolithography has reached its resolution limitation and the other competing technologies are either too slow such as e-beam lithography or too expensive such as EUV system. In this thesis, BCP lithography is utilized to fabricate magnetic nanostructure and the corresponding magnetic properties are explored. The polystyrene- b-polydimethylsiloxane (PS-b-PDMS) diblock copolymer with different molecule weight is used to generate various sizes of robust silica pattern after solvent annealing and reactive ion etching. Pattern transfer methods are developed to convert the silica pattern into functional materials, including magnetic materials like cobalt, Co/Pd, FePt and CoFeB magnetic tunnel junctions (MTJ), and MoS2 monolayers. For magnetic nanowire arrays, the interactions between neighboring wires are investigated. For perpendicular MTJ nanopillar arrays, the size-dependent switching behavior and magnetostatic effects between two layers are analyzed. MoS 2 monolayers are patterned into features such as nanodots, nanorods and nanomeshs and the corresponding photoluminescence are characterized. Finally, machine learning and deep learning algorithms are the first-time ever demonstrated to model the BCP self-assembly process. The built model is able to recognize different BCP patterns and predicting the resulting morphology and pattern quality based on experimental process parameters. With this model, the BCP self-assembly can be further optimized toward industrial-grade production.
by Kun-Hua Tu.
Ph. D.
Wang, Hengbin. "Supramolecular self-assembly of conjugated block copolymers /". 2003. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3077080.
Texto completo da fonteChiang, Yeo-Wan, e 蔣酉旺. "Self-assembly of Chiral PS-PLLA Block Copolymers". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06782467113909150888.
Texto completo da fonte國立清華大學
化學工程學系
96
The self-assembly of synthetic supramolecules has been inspired by using the secondary interactions, and has already created a large number of nanoscale architectures. Among self-assembled architectures, helical morphology is probably the most fascinating morphologies in nature. Chirality of compounds has been referred to one of the main origins for the formation of helical textures. For the self-assembly of block copolymers (BCPs), one-, two-, or three-dimensional periodic nanostructures can be easily tailored by molecular engineering of synthetic BCPs. By taking the advantage of the BCP self-assembly and the specific configuration of chirality, chiral block copolymers (BCP*), poly(styrene)-block-poly(L-lactide) (PS-PLLA), containing both achiral PS and chiral PLLA blocks was designed for self-assembly. A unique transmission electron microscopy observation and small-angle X-ray scattering pattern for the self-assembled PS-PLLA nanostructure revealed the novel morphology of a hexagonally packed nanohelical phase. On the basis of the geometric features, the space group of the new nanohelical phase was identified as P622. The formation of the nanohelical phase from the BCP* self-assembly is thus referred to the contribution of chiral entities and might provide a new concept for design of the helical morphology in bulk. Because of large-size polymeric chains, the molecular chain dynamics is critical for the formation of stable and equilibrium morphology. Thermally induced transitions between the microphase-separeated morphologies are well known such as a HEX to BCC, a HPL to gyriod and a gyroid to HEX phase by varying the Flory interaction parameter x (a function of 1/T) at fixed block copolymer composition. In this study, to finely control formation of the helical morphology, metastability and order-disorder transition temperature for the nanohelical phase was examined by using time-resolved small-angle X-ray scattering and corresponding transmission electron microscopy. The phase transition of PS-PLLA after solution casting from a HPL to nanohelix was obtained by thermal annealing. With substantial time for annealing, the formed nanohelical phase might transform to a HEX phase; suggesting that the nanohelix is a metastable phase. Also, molecular weight effect on the formation of the nanohelical morphology was examined at a constant composition. The appearance of a gyriod instead of nanohelical phase for low-molecular-weight PS-PLLA indicates the formation of nanohelical phase is dependent upon segregation strength. To manipulate the three-dimensionally packed nanohelical morphology from BCP* in bulk, various stimuli were applied such as crystallization and shear stress. The self-assembled nanohelices can transform into crystallization- and shear-induced cylinders. The stress-induced cylinders (stretched nanohelices) were found thermally reversible upon annealing through undulation. As a result, the hexagonally packed PLLA nanohelices in PS matrix of chiral PS-PLLA block copolymers appear as spring-like behavior in response to the applied stimuli. This unique phase behavior thus creates a possible way for manipulating switchable nanohelical structures in practical applications. Since the crystallization-induced cylinder from nanohelical phase can be achieved by control of crystallization temperature, comprehension of the crystalline details within the nanohelical microdomain is critical. Various crystalline PS-PLLA nanostructures were obtained by controlling the crystallization temperatures of PLLA (Tc,PLLA) at which crystalline nanohelices (PLLA crystallization directed by helical confined microdomain) and crystalline cylinders (stretching of helical nanostructure dictated by crystallization) occur while Tc,PLLA
孫睿妤. "Studies of self-assembly block copolymers/DNA complexes structure". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/16614419883824841314.
Texto completo da fonte國立清華大學
化學工程學系
93
The interaction of polycation-DNA can form complexes with DNA resulting in the coil–globule conformational transition in the DNA molecules and DNA condensation. It was proposed that polycation-DNA complex formation is entropy driven and electrostatic force due to the ion pairs formed between positively charged groups of polycation molecule and the phosphate groups of DNA. In our studies, we try to use cationic diblock copolymer and homopolymer as polycations, and complex with DNA to investigate the actual internal structure. This is more one parameter in cationic diblock copolymer than homo-polycation to control the structure of complexes. The level of aggregation is related to the properties of the components as well as to the medium and external conditions of the polyplexes formation, so that we carried out studies that effect of ionic strength, temperature on polyplexes. The internal structure of DNA polyplexes formed with P4VP(CH3I) and PS-P4VP(CH3I) are investigated by POM, SAXS and TEM. The results were hexagonal packing of DNA in both complexes in aqueous solution. This salt-induced phase behavior was found for P4VP(CH3I)/DNA. The surprising studies are temperature-induced ordering packing for DNA and PS sphere in the complexes and the processes were irreversible. According to our results, we proposed simple models for both complexes to reveal the structures.