Дисертації з теми "Liquid Crystalline Behavior"
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Tenneti, Kishore Kumar Li Christopher Yuren. "Nanoscale hierarchical phase behavior of liquid crystalline block copolymers /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2764.
Повний текст джерелаMoilanen, A. (Anu). "Self-association, compatibility, and strengthening behavior of liquid crystalline oligomers." Doctoral thesis, University of Oulu, 1998. http://urn.fi/urn:isbn:9514250915.
Повний текст джерелаJEONG, SEUNG YEON. "Liquid crystalline behavior of mesogens formed by anomalous hydrogen bonding." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1304649634.
Повний текст джерелаThorson, Todd James. "Phase behavior and stimuli response in lyotropic liquid crystalline templated photopolymers." Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/2646.
Повний текст джерелаSimoes, Ricardo J. F. "Mechanical behavior and performance of injection molded semi-crystalline polymers." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc5528/.
Повний текст джерелаVerploegen, 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.
Повний текст джерелаIncludes 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.
Zhou, Weijun Kornfield Julia A. Kornfield Julia A. "Dynamics and shear alignment behavior of a model thermotropic liquid crystalline polymer /." Diss., Pasadena, Calif. : California Institute of Technology, 2001. http://resolver.caltech.edu/CaltechETD:etd-08292008-110129.
Повний текст джерелаKhennache, Omar. "Factors influencing product microstructure and the injection molding behavior of liquid crystalline polymers." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74663.
Повний текст джерелаIn the present work, broad range of material properties, including specific heat, thermal conductivity, thermal diffusivity, and shear viscosity of a commercial LCP injection molding resin have been determined experimentally. In addition, a detailed experimental study has been made of the crystallization kinetics of this LCP resin. The study showed that the resin undergoes two crystallization mechanisms, a fast and a slow mechanism, depending on the temperature and the cooling rates.
Various experimental techniques, to characterize the microstructure of the molded parts, including morphology, orientation, crystallinity and mechanical properties, have been developed and used. An effort is made to explain the results. Furthermore, composite theory is employed to explain the mechanical properties in light of microstructural observations. Overall, the present work represents the most comprehensive effort to date to study and explain the processing-microstructure-property relationships for injection molded LCP's.
Ren, Wanting. "Structure-property Relations of Siloxane-based Main Chain Liquid Crystalline Elastomers and Related Linear Polymers." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16248.
Повний текст джерелаKoch, Karin [Verfasser]. "Ferronematic phases with strong coupling behavior based on liquid crystalline polymer decorated nanoparticles / Karin Koch." München : Verlag Dr. Hut, 2021. http://d-nb.info/1240540086/34.
Повний текст джерелаQian, Chen. "Linking the Rheological Behavior to the Processing of Thermotropic Liquid Crystalline Polymers in the Super-cooled State." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/75005.
Повний текст джерелаPh. D.
Murphy, Lindsay Adams. "Morphological investigation of AFR-PEPA-N imide oligomers and their cured polyimides and the remodification of AFR-PEPA-N to achieve liquid-crystalline behavior." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1174.
Повний текст джерелаKress, Oliver Herbert [Verfasser], Tanya [Akademischer Betreuer] Ostapenko, Jörg [Gutachter] Enderlein, and Simone [Gutachter] Techert. "The Viscoelastic Response of Liquid Crystalline Fibers Formed By Bent-core Molecules : From Microscopic Ordering to Macroscopic Behavior / Oliver Herbert Kress ; Gutachter: Jörg Enderlein, Simone Techert ; Betreuer: Tanya Ostapenko." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1200209176/34.
Повний текст джерелаWongkhan, Kittiya. "Synthesis and applications of palladium complexes : Part I. The synthesis, single crystal structures and liquid crystalline phase behavior of alkoxy substituted Tolans; Part II. Palladium-complexes of thioureas and phosphine sulfides." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2139/.
Повний текст джерелаMateer, Donna Louise. "The liquid-crystalline behaviour of photographic sensitising dyes." Thesis, University of Salford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360349.
Повний текст джерелаMadden, Andrea. "Phase behaviour of side-chain liquid-crystalline polymers." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241165.
Повний текст джерелаLavine, Marc Stuart. "Modelling of defect behaviour in nematic liquid crystalline materials." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627290.
Повний текст джерелаDuesing, Peter Michael. "Effects of pressure on lyotropic liquid-crystalline phase behaviour and structure." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294919.
Повний текст джерелаFlood, Joseph. "Solution and liquid crystalline properties of sodium lauroyl methyl isethionate/water mixtures." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/solution-and-liquid-crystalline-properties-of-sodium-lauroyl-methyl-isethionatewater-mixtures(d9f043f2-3ca6-4a13-b3f0-d5d5eae83bfc).html.
Повний текст джерелаStimson, Lorna M. "Phase behaviour of macromolecular liquid crystalline materials : computational studies at the molecular level." Thesis, Durham University, 2003. http://etheses.dur.ac.uk/3144/.
Повний текст джерелаUhl, Benedikt [Verfasser]. "Adsorption behavior and structure formation of ionic liquids on single crystalline surfaces / Benedikt Uhl." Ulm : Universität Ulm, 2017. http://d-nb.info/112552815X/34.
Повний текст джерелаGana, Inès. "Caractérisation physique et chimique des substances à activité thérapeutique : application aux études de profil de stabilité et de préformulation." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCB164/document.
Повний текст джерелаThe development of a drug for a given therapeutic target requires several steps, which can be summarized by drug screening, a preclinical phase and a number of clinical phases. These steps allow the selection of an active substance and a verification of its therapeutic efficacy and toxicological safety. The latter two criteria define the quality of the drug, which once demonstrated, must be guaranteed throughout its shelf life. Quality is assessed through stability studies that are carried out with the raw material of the active substance (preformulation phase) and with the final product. The intrinsic stability of the active substance depends on its chemical and physical properties and their characterization is the core of the stability studies, which in addition consists of sensitivity studies of the active pharmaceutical ingredient (API) for environmental factors that can modify the intrinsic properties of the substance. The approach presented in this work is based on the one hand on the assessment of the chemical stability, i.e. the reactivity of APIs through chemical purity studies and forced degradation in solution, and on the other hand on the assessment of the physical stability. For the latter, crystalline polymorphism is of great importance, as is the ability of the API to form hydrates or solvates. The study of crystalline polymorphism is based on the construction of pressure-temperature phase diagrams in accordance with thermodynamic requirements leading to the stability condition domains of the different crystalline forms. The stability behavior of five APIs used or meant for oral applications has been studied as part of this work. The chemical analysis of tienoxolol, an antihypertensive drug, has demonstrated its sensitivity for hydrolysis and oxidation. Seven degradation products were identified and patterns of fragmentation have been established. Pressure-temperature phase diagrams have been constructed for bicalutamide and finasteride, drugs against prostate cancer, using a topological approach based on data available in the literature. The study demonstrates that the thermodynamic relationship (enantiotropy or monotropy) between crystalline forms under ordinary conditions can change depending on the pressure. This is important for drug development as it demonstrates how stability information can be obtained by standard laboratory measurements accessible to industrial research laboratories without the necessity to carry out experiments under pressure. The topological approach for the construction of phase diagrams has subsequently been validated by measuring transition temperatures as a function of pressure. Experiments have been carried out with benzocaine, a local anesthetic, and with cysteamine hydrochloride, a drug used against cystinosis. Two crystalline forms were observed in the case of benzocaine. They exhibit an enantiotropic relationship that becomes monotropic at high pressure. For cysteamine hydrochloride, a new crystalline form (form III) was discovered. The thermodynamic relationship between the new form III and the known form I is enantiotropic for the entire temperature and pressure range. Cysteamine hydrochloride’s sensitivity to water has been studied, as it is hygroscopic. It has been demonstrated that it becomes deliquescent in the presence of water and no trace of a hydrate has been found. Finally, a study combining thermal and chromatographic methods showed that, under the effect of temperature, cysteamine hydrochloride turns into cystamine in the solid as well as in the liquid state, The latter is known to be an important impurity of cysteamine hydrochloride. In conclusion, the approach developed in this work allowed to characterize the stability properties of a number of APIs and to determine the factors that may change these properties and influence the intrinsic stability (...)
Wu, Tzu-Yen, and 吳姿燕. "Electrorheological Behavior of Nematic Liquid Crystal and Liquid Crystalline Copolymer." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/7pa3s6.
Повний текст джерела國立臺北科技大學
有機高分子研究所
97
This study consist of two parts. The first part focuses on the electrorheological effect of homogeneous electrorheological fluid in regard to liquid crystalline copolymer, PBLG-PDLG Poly(γ-benzyl L-glutamate-co-γ-dodecyl L-glutamate),the molecule packing of α-helical poly(γ-benzyl L-glutamate) with n-alkyl side chain of various lengths (number of carbons in the alkyl group m = 12), were studied by means of 1H-NMR and polarized optical microscope. The liquidcrystalline copolymer with the permanent dipole along the helix axis is expected to show electrorheological effect under DC field. This study employed a parallel plate rheometer, Physica MCR 301, to investigate the viscosities of liquid crystalline copolymer under the changes in electric field strength. An apparent increase in viscosity was found when the electric field was applied. It was attributed to the formation of molecule structures along the electric field resulted from the interaction between the liquid crystalline molecules. The flow resistance was consequently enhanced. The second part is investigated the rheological properties of liquid crystal compound, 7OCB ( 4-cyano-4’-n-heptyloxybiphenyl ), subjected into an electric field. The viscoelastic properties of the liquid crystals were measured by the parallel plate viscometer, Physica MCR 301. Similar to the previous study, the electrorheological behavior was depended on the electric field strengths and temperatures. Within the temperature range of a nematic phase, the shear stress increase with amplitude of the electric field, and has different change with the temperature.
Fynewever, Herb. "Phase behavior and local structure of liquid crystalline polymers." 1998. http://catalog.hathitrust.org/api/volumes/oclc/42697798.html.
Повний текст джерелаTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 115-124).
Chiu, Chien-Yu, and 邱建育. "Study of the Transient Electrorheological Behavior of Liquid Crystalline Polymer." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/36457437598953132868.
Повний текст джерела東海大學
化學工程學系
85
PHIC為帶有偶極矩之棒型高分子,具有成為單相型電流變流體的潛 力。本研究係使用RDAII 流變儀對主鏈型液晶高分子PHIC的溶液進行流變 鬆弛測試。所進行的測試方式是將試樣在定電場下進行固定剪切率的運動 至達到穩態後將電場去除然後觀察其力矩鬆弛與時間的關係。由實驗結果 發現此鬆弛行為是剪切率、電場強度與溶液的形態的函數。所有的鬆弛行 為有兩種基本模式:其一為單調遞減模式,另一種模式則有先出現下凹再 緩增逼近穩態值。在所探討的剪切率範圍內,低濃度的等向性溶液僅顯現 第一種模式;兩相性溶液則在低剪切率時遵循第一種模式,在較高的剪切 率則轉成第二種模式。在兩種模式中,高剪切率與高電場強度都會導致鬆 弛過程的初期應力有較迅速的降低。在力矩標準化之後,定剪切率下不同 電壓的單調遞減模式都可以整合成一條統一的主線。而下凹緩增模式則於 特定高剪切率範圍內亦可以用一條主線加以統合。 We studied the relaxation behavior of solutions of a liquid crystalline polymers, Poly(n-hexyl isocyanate), or PHIC which has the potential to be a novel single phase electrorheological(ER) fluid. The relaxation from an imposed electric field of a steady shear was found to be a function of shear rate, electric field strength and morphology of the solutions. Two patterns of the relaxation were observed. One of them was simply a monotonic decay and the other exhibited a under shoot followed by a gradualapproach to the new steady value. Over the shear rates investigated, the isotropic solutions always followed a monotonic pattern while the biphasic solutions exhibited both patterns depending on the shear rates. In both patterns, higher shear rates and higher field strengths induced a more rapid reduction of the stress in the beginning of the relaxation process. It was found that for both morphologies, the monotonic decaying curves can be superposed into a master curve by normalization, while for the pattern of under shoot, the master curve exits only for some range of high shear rates.
WANG, YING-HONG, and 王穎鴻. "Liquid crystalline schiff base with cyanate terminalse synthesis and cure behavior." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/39571104719746905205.
Повний текст джерелаChou, Jui-wen, and 周瑞雯. "A study of crystallization behavior and liquid-liquid phase separation of immiscible binary crystalline polymer blends." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/67235063942393408372.
Повний текст джерела國立臺灣科技大學
工程技術研究所材料科技學程
89
We use polarized optical microscopy(POM), differential scanning calorimeter (DSC) and stactic birefringence to probe the liquid-liquid phase separation as well as the crystallization and the melting behavior of a binary crystalline polymer blends of syndiotactic polypropylene(sPP) and random poly(propylene-co-ethylene)(PEP). We find that both liquid-liquid phase separation rate and crystallization rate are greatly influenced by the initial melting temperature and final crystallization temperature. The resulting structures of blends samples vary with the initial temperature, the crystallization temperature, as well as the polymer component. Due to the competition between liquid-liquid phase separation and crystallization of both components, the blend samples are immiscible even when the temperatures above the melting points. While from the static birefringence experiment, we can not get the transition temperature from two separated liquid-liquid phases to one disordered phase. This is due to the fact that though both components are immiscible, the separated domains are still randomly distributed such that birefringence intensity is zero. When a few amount of component B is added to component A, the crystal growth rate as well as the crystallinity of A decrease; however the nucleation rate increases, such that the total crystallization rate reaches a maximum when the blending ratio of sPP and PEP are in the range of 3/7 and 1/9.
Zhou, Weijun. "Dynamics and shear alignment behavior of a model thermotropic liquid crystalline polymer." Thesis, 2001. https://thesis.library.caltech.edu/3274/1/Zhou_w_2001.pdf.
Повний текст джерелаYang, kai-neng, and 楊凱能. "Dielectric and Photochromic Behavior in Comb-Shaped Liquid Crystalline Polymers Containing Azobenzene Side Group." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/04889805312042203409.
Повний текст джерела輔仁大學
化學系
88
Abstract Photochromic dye molecules (Such as azobenzenes) change their molecular shape upon photo irradiation, and this property has been used extensively to control the orientation of liquid crystals by light. Besides, azobenzene liquid crystals have been developed, in which the azobenzene moiety plays roles as both mesogens and photosensitive chromophores. The trans form of azobenzene derivative is rod-like, which stabilizes the LC phase, whereas the cis form is bent and destabilizes the LC phase when it is present. Therefore, the trans-cis photoisomerization of azobenzene in the LC phase can cause disorganization of the phase structure. In addition, the cis-trans back-isomerization can take place either by a thermal process or a photochemical process. All these properties enable the comb-shaped side-chain LC polymer (SCLCP) containing an azobenzene moiety a promising material for optical switch and image storage. This study synthesized six SCLCPs of this type in which the azobenzene moiety was attached with different electron-withdrawing group (i.e.,-NO2,-CN,-COCH3) on the para position, and the soft spacer used was either (-CH2-)3 or (-CH2-)9 segment. All their structure were characterized by GPC, NMR, IR, UV, DSC, TGA and POM. All there SCLCPs were stable up to 250℃, and exhibited some stable mesophases (mostly Smectic phase), as confirmed by POM and DSC observations. Photoirradiation was performed with a 100W high-pressure Hg lamp. The change in transmittance of 365 nm absorbance band (corresponding to π-π* transition of trans-azobenzene) was monitored as a function of irradiation time. These results showed that the spacer length and electron-withdrawing capability were the two factors which enhancing the backward isomerization processes, but not for the forward trans-cis isomerization process, Dielectric relaxation studies exhibited a more clear-cut picture for the mesophase transitions of these SCLCP than that of DSC and POM showed. The two factors mentioned above also affects the location of occurrence of β-relaxation.
Tasi, Yi-Chan, and 蔡易展. "Phase Behavior and Thin-Film Properties for Solution-Processed Field-Effect Transistor Based on Liquid-Crystalline Semiconductor Oligothiophenes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99562959154036285179.
Повний текст джерела國立暨南國際大學
應用化學系
98
In view of the increasing popularity of Organic Field Effect Transistor(OFET). In order to implement the industrialization process, therefore, the solution process becomes an important of development goals. In this study, we used highly-soluble oligothiophene derivatives as organic active layer. These thin film were deposited by vacuum evaporation and solution process. In the vacuum evaporation process, we previous used to modify substrate surface by self-assembled monolayer(SAM), octadecyltrichlorosilane(ODTS) and Hexamethyldisilazane(HMDS). Then, rubbing to further improve the arrangement of SAM. The results of this series of results to that NTETB has the best electrical properties, the carrier mobility of up to 3.51×10-2 cm2/Vs and on/off current ratio is 4.04×102. Then, by atomic force microscopy and X-ray diffraction to investigate the relationship between film morphology, molecular arrangement and electrical property. Also because NTETB have the best performance, so a precursor of solution process in this study. After optimizing the conditions of the thin film, the carrier mobility of up to 5.79×10-2 cm2/Vs, but the leakage current was found. Then, using Differential Scanning Calorimeter(DSC) to measure the physical properties and through various heat treatment process. Finally, we analyze the thin film phase change process by polarized optical microscope and X-ray diffraction.
Shih, Yuh-Jinn, and 施裕進. "Synthesis and Mesomorphic Behavior of Thermotropic Side Chain Liquid Crystalline Polysiloxanes Containing an Oligo ( ethylene glycol ) Monomethyl Ether-Substituent." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/94138504311259099036.
Повний текст джерелаWei-HanChang and 張維瀚. "Calorimetric Study of the Additive Effects on the Gel to Liquid-Crystalline Phase Transition Behavior of Catanionic Bilayer Membrane." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/46008407079786464985.
Повний текст джерела國立成功大學
化學工程學系碩博士班
100
Four ion pair amphiphiles(IPAs) of different hydrocarbon chain lengths with symmetric and asymmetric hydrocarbon chains were prepared from cationic and anionic surfactants by the precipitation in this work. By using differential scanning calorimetry(DSC), the thermotropic transition behavior from gel to liquid-crystalline state was measured for bilayer membranes of these lipid-like catanionic surfactants. Moreover, the effects of additives(cholesterol, vitamin E, and vitamin E acetate) in catanionic bilayer membranes on phase transition temperature, enthalpy change and entropy change were determined. The experimental results showed that the phase transition temperature is higher for catanionic surfactants with higher total carbon number in the hydrocarbon chains. And for the catanionic surfactants with the same total carbon number in the hydrocarbon chains, the phase transition temperature is higher for the symmetric one than that with asymmetric one. No consistent trend in enthalpy changes, however, was exhibited by the different catanionic surfactants. With the addition of cholesterol, vitamin E, and vitamin E acetate in the bilayer membrane of catanionic surfactants, the phase transition temperatures were found to be unaffected. On the other hand, the enthalpy and entropy changes decreased with the increase of these three additives.
Chen, Wen-Ren, and 陳文仁. "The research on the phase behavior and optical-electro properties in the (nematic/discotic) and (nematic/chiral dopant) liquid-crystalline composite system." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/94275100733319875743.
Повний текст джерела元智大學
化學工程學系
93
Two binary liquid-crystalline composite systems were composed of (a nematogen and a discotic mesogen) and (a nematogen and a chiral dopant). The phase behaviour and optical-electro properties of two binary composites have been investigated. The former system yielded an induced SmA phase in the range of 80/20~30/70 wt.%. The layer-stacking structure of binary composite was proposed in the SmA phase. The latter system formed N* phase in the S811 content under 20 wt.%. The frusted phases, BP and TGBA*, and the SmA* phases were formed in the range 25~30% and 40~80%. The orientational ordering of the binary composites increased with increasing the chiral dopant content and decreasing sample temperature. The optical-electro properties were also investigated under the external electric field.
ZHANG-JIAN, GUO-PING, and 張簡國平. "Synthesis、molecular micro-structure and mesomorphic behavior of terminally carboxyl oligo (ethylene oxide) monomethyl ethers-substituted side chain liquid crystalline polysiloxane and copolysiloxane polymers." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/98239961271486733827.
Повний текст джерелаChou, Yen-Ling, and 周彥伶. "Synthesis and Optical Behaviors of Novel Ternary Liquid Crystalline Copolymers." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/76572301030679792974.
Повний текст джерела國立成功大學
化學工程學系碩博士班
96
In order to investigate the effect of temperature and UV irradiation on the reflective band of cholesteric liquid crystals, a series of novel side chain liquid crystalline binary (P1 and P5) and ternary (P2~P4 and P6~P8) polymers consisting of one (N=N or C=C) or dual (N=N and C=C) photochromic segments were synthesized and characterized considering their liquid crystalline, optical, and photochromic properties and their thermal stability. Monomers were polymerized with various feed compositions under the same conditions. The synthesized polymers, P1-P8, were identified using FT-IR, NMR, and EA. Thermal and optical properties were estimated using DSC, TGA, XRD, and POM instruments. Molecular weight of polymers was calculated to be between 7.0 x 103 and 1.5 x 104. Thermal resistance was found to be higher than 300oC. An increase of temperature was found to cause a blue shift of reflective band. Polymer P1 revealed highly thermal sensitivity. It is expected to be used as a thermal sensor. Contrary to that, introduction of a chlorine atom onto benzene ring of liquid crystal molecule reduced hermal sensitivity of polymer’s reflective band. For polymer P5, variation of the reflective band was limited between 400 and 450 nm. Polymers synthesized in this investigation are expected to be used as novel materials in the field of thermal sensing and color image recording techniques.
Li, Jiong-Xian, and 李炅憲. "Pretransitional Behaviors from the Isotropic to Liquid Crystalline Phase of Liquid Crystals Confined in Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/kv55hm.
Повний текст джерела國立交通大學
光電科技學程
107
The purpose of this study is to adopt dielectric spectroscopy to observe the change of optical textures and dielectric behaviors of liquid crystals (LCs) injected into sandwich-type cells with distinct types of spacers (rod and ball) during the isotropic to LC phase transition. It is found that the spacer will lead to a textural formations and generate a pretransitional (PT) phase for both rod- and ball-spacer-contained LC cells without affecting their dielectric constants. In order to confirm the effect of spacer on observed results, we also fabricated a counterpart in which there is no spacer in the electrode area. The results indicated that the PT phase is absent in the no-spacer LC cell and the regularity of the dielectric constant is different from those of cells with spacers (rod type). On this basis, the dielectric properties and textural transitions of various nematic LCs, including CYLC31 and HDE with positive dielectric anisotropy (+∆) and MLC6608 and ZLI2806 with negative dielectric anisotropy (–∆) injected in rod-spacer-contained cells. The result shows that the regularity of dielectric spectrum changed as a function of the temperature is affected by the magnitude of ∆, In other words, the larger ∆ of positive LCs in rod cells will lead to the induction of PT phase easier. Finally, we investigate the formation of PT phase in spacer-contained CLC cells by doping various contents of chiral agent R5011 in nematic host E44. By dielectric spectrum and textural observation result, it shows that the dielectric signal for the determination of the PT phase in the ’(T) becomes intense and the clearing temperature point gets decreased with increasing dopant concentration of R5011 in E44. As a result, we conclude that the generation of PT state in spacer-contained LC cells is determined by the magnitude of ∆ and the texture formation is affected by the shape of spacer.
Wei-ChiehChen and 陳偉杰. "Synthesis and Photo-Behaviors of Amphotropic Liquid Crystalline Monomer with Cholesteryl Group." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/61121663652426229454.
Повний текст джерела國立成功大學
化學工程學系
102
In this work, we synthesized a liquid crystalline monomer CCM, which possess amphotropic liquid crystalline properties. Dependence of selective reflection on molecular arrangement and temperature effects were studied. Furthermore, a novel diblock copolymer PS-b-PCCM was synthesized via ATRP method and a homopolymer PCCM was synthesized using AIBN. The amphotropic liquid crystalline monomer CCM shows thermotropic cholesteric liquid crystal phase at a temperature higher than 90°C. Lyotropic cholesteric liquid crystal state exists in some proper solvents. Increase of temperature to a specific point, some CCM monomers were found to be polymerized. The partially polymerized cholesteric liquid crystal shows some higher order and more significant selective reflection. The results of lyotropic liquid crystalline CCM suggest that this predesigned CCM is available for using as a solvent sensor and tunable bandgap filter.
Yun-ChiehSung and 宋昀潔. "Optical Behaviors of Cholesteric Liquid Crystalline Polyester Composites with Various Chiral Photochromic Dopants." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/79839908142666583237.
Повний текст джерела國立成功大學
化學工程學系碩博士班
98
To investigate the induction of photonic arrangement using chiral photochromic dopants, a series of novel chiral photochromic dopants and main-chain liquid crystalline polyesters were synthesized. The molecular structure of the synthesized compounds was identified using NMR, FTIR, and elemental analyses. Phase transition temperature and the liquid crystal phase determination of the synthesized polymers were estimated using DSC, WAXD and POM analyses. Furthermore, to investigate the dependence of UV light irradiation on incident reflection band, we mixed main-chain liquid crystalline polymers with chiral photochromic dopants to form the liquid crystalline polymer blends. The influence of dopant concentration and the solubility in liquid crystalline polymer blend were also studied. Due to the photochemical reaction of the chiral photochromic dopants, the reflection band of the cholesteric liquid crystalline polymers could be adjusted and tuned at visible light region. A real image recording of chiral photochromic liquid crystalline polymer blend was achieved by exposing UV light through a mask.
Yeh, Ming-che, and 葉銘哲. "Design and Synthesis of the Discotic Liquid Crystalline Materials for Controlling Mesomorphic Behaviors and Supramolecular Assembly." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/85630693117595133196.
Повний текст джерела國立中山大學
化學系研究所
101
Discotic liquid crystals (DLC) have been reported with a large number of discoid cores to improve the degree of intermolecular ordering because the liquid crystals own to self-assembly into columnar stacking and self–healing ability. In my research, a series of disc-like π-conjugated molecules based on aromatic rigid cores have been newly synthesized. I focus on the hexaazatrinaphthylene (HATN) and dibenzo-[a,c]- phenazine as aromatic cores, changing different side chains to control the mesomorphic behavior and their supermolecular assembly.