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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"cholesteric"”.
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The interplay between order and disorder in cholesteric hydroxypropyl cellulose films
… by selective absorption. The formation of a cholesteric liquid crystalline phase is one route to achieve such structuring on the nanoscale. An especially promising candidate is hydroxypropyl cellulose (HPC), a bio-sourced, bio-compatible and water-soluble polymer, which spontaneously …
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Nondestructive evaluation of fiberglass using cholesteric liquid crystals : review of techniques and industrial applications
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980.
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The asymmetric synthesis of hexahelicene : the photocyclization of 2-styrylbenzo[c]phenanthrene in cholesteric liquid crystals and chiral media
Contains fulltext : MMUBN000001_065981790.pdf (Publisher’s version ) (Open Access)
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Nonlinear macroscopic description of liquid crystalline elastomers in external fields
… we investigate the macroscopic behavior of cholesteric and nematic SCLSCEs in external electric and mechanical fields. We characterize the respective liquid crystalline state using the director field and describe the current state of mechanical distortion by a displacement field. The …
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Novel chiral liquid crystal organic-inorganic hybrid nanoparticle systems : Design, synthesis and investigation
… crystal materials which exhibit room temperature cholesteric mesophases. These cholesterol based materials were then attached to silsesquioxanes. Both materials have low melting points and low transition temperatures. Phase diagrams, contact and miscibility experiments were performed in order to …
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Transport of Liquid Phase Organic Solutes in Liquid Crystalline Membranes
… separations. An enantioselective cholesteric liquid crystal membrane was fabricated and evaluated using the nonchiral HPLC-CD system. The cholesteric LC membrane showed enantioselectivity in the cholesteric phase where activation energies of permeation for 1-phenylethanol …
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Stereocomplex poly (methyl methacrylate) fibers and self-reinforced composites and structural color of butterflies and beetles - characterization, replication and mimicry
… beetle Chrysina gloriosa, which were shown to be cholesteric focal conic defects lined on the surface.
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Order reconstruction and solution landscapes for liquid crystalline systems
… between uniaxiality and biaxiality in cholesteric liquid crystals, and a way to potentially observe biaxiality experimentally.
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Photonic Properties of Liquid Crystalline Hydroxypropyl Cellulose in the Solid-state
… several cellulose derivatives exhibit a cholesteric liquid crystalline phase in solution, displaying vibrant structural colours. Amongst them, water-soluble hydroxypropyl cellulose (HPC) is ideal for developing sustainable photonic materials to replace toxic dyes and pigments. The …
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The confined self-assembly of photonic pigments: from synthetic polymer brushes to sustainable cellulosic colloids
… wood or cotton, which can self-organise as a cholesteric liquid crystal phase to form a helicoidal nano-architecture that reflects the visible light. CNCs are sustainable and biocompatible, but these large anisotropic colloids have slow kinetics and a complex self-assembly process. The second …
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Chiral self-assembly of cellulose nanocrystals for photonic films
… colloidal particles that spontaneously form a cholesteric liquid crystal phase in aqueous suspension. This helicoidal configuration can be preserved as the suspension dries, resulting in films with vibrant structural colour. Although CNCs have attracted growing interest from different research …
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Development of 'In vitro' intestinal models to study the pharmacology of drugs affecting the gastrointestinal tract in normal and diseased conditions. Development of a cell culture model for intestinal pharmacology.
… of cocultures seeded onto silicone elastomers or cholesteric liquid crystal substrates (LC) were assessed for their ability to produce a collective response to KCl application. Attempts were made to detect any deformations of the substrate surface due to the exposure to KCl and NA. Cholesteric LC …
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Polarization-independent Liquid Crystal Devices
… device concepts: PDLC and Polymer-Stabilized Cholesteric Texture (PSCT), homeotropic LC gels, thin polymer film separated double-layered structure, and double-layered LC gels. In the low voltage regime, both PDLC and PSCT have a strong light scattering. However, as the voltage exceeds a …
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Towards Mechanochromic Devices using Biocompatible Hydroxypropyl Cellulose
… forms structural colours via the formation of a cholesteric, liquid crystalline mesophase, termed photonic HPC. Intrinsically biodegradable, edible and mechanochromic, photonic HPC can be manufactured at scale and low-cost in a simple formulation. A high reflectivity also allows for easy …
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Tunable organization of cellulose nanocrystals for controlled thermal and optical response
… organization. Shear oriented films disrupted the cholesteric organization, generating highly aligned structures with high optical transparency. The resultant CNC organization present in all nanostructured films was estimated by a second order statistical orientational distribution based on two- …
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Investigations into the mechanics of connective tissue
… materials of carbon nanotube (CNT) elastomers, cholesteric liquid crystal elastomers (CLCEs), and 3D polydomain liquid crystal elastomers (3DLCEs). The setup accurately demonstrated the incompressibility of PDMS, even at short time scales, and demonstrated how DIC can map the inhomogeneity of …
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Liquid Crystal Materials And Tunable Devices For Optical Communications
… we have investigated the polymer-stabilized cholesteric LC (PSCLC). Combining the curing temperature effect and high birefringence LC, a polarization independent fiber-optical device is realized with over 30 dB attenuation, ~12 Vrms drive voltage and 11/28 milliseconds (rise/decay) response …
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Applications Of Linear And Nonlinear Optical Effects In Liquid Crystals
… of such structure is the presence of bandgap. Cholesteric liquid crystals are known to possess bandgap for one of two circular polarizations of light. However, unlike the cholesterics the bandgap of the proposed structure is independent of polarization of normally incident light. This means …
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Optische und mechanische Untersuchungen an cholesterischen Elastomerfilmen
Cholesterische Phasen reflektieren zirkular polarisiertes Licht einer definierten Wellenlänge. Durch die Kopplung der Mesophase an das Polymernetzwerk besteht bei cholesterischen Elastomeren die Möglichkeit, die Selektivreflexionsbande durch eine mechanische Deformation zu verschieben. Allerdings …
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Cellulose photonics: designing functionality and optical appearance of natural materials
Cellulose is the most abundant biopolymer on Earth as it is found in every plant cell wall; therefore, it represents one of the most promising natural resources for the fabrication of sustainable materials. In plants, cellulose is mainly used for structural integrity, however, some species organise …