Download or read book Molecular Engineering of Side chain Liquid Crystalline Brush Copolymers for Photonic and Nanoporous Membrane Applications written by Prashant Deshmukh and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Platform of Functional Liquid Crystalline Copolymers Synthesis Morphology Properties and Applications written by Dennis Ndaya and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of novel, complex and tailored macromolecules that present and combine unique features such as stimuli responsive, self-assembly and hierarchical architectures for applications in fields ranging from healthcare, energy to engineering, is one of the major challenges that need to be addressed by a polymer chemist. One way to address this, is through the combination of monomers with desirable roles such as stimuli responsive (liquid crystalline), solubility (polar or non-polar), targeting and payload release functional monomers. Polymerization techniques such as controlled and living polymerization enables the regulation of the connectivity and composition of these diverse monomers in the synthesis of block, random or gradient copolymers. Ring-opening metathesis polymerization (ROMP) majorly employed in most of the work in this thesis, is a robust living polymerization technique which delivers highly functionalized block or random copolymers that serves as nanotemplates (chapter 2), nanoporous membranes for separation (chapter 3), photonic crystals (chapter 4), shape memory devices (chapter 5), stimuli responsive optical materials (chapter 6), drug delivery vehicles and imaging agents (chapter 7). This dissertation focuses on a new platform for the synthesis of novel liquid crystalline polymers, their architectures, morphologies, properties and applications. The control of composition and polymer architecture is key in tuning the properties of copolymers for desired applications. Side-chain Liquid Crystalline Copolymers (SCLPs) which combines the basic properties of conventional polymers and liquid crystals, exhibit low viscosity, unique self-assembly as compared to linear copolymer counterparts due to reduced entanglements. Liquid crystalline block copolymers (LCBCPs) that comprises of brush-like semicrystalline or amorphous units and comblike side chain liquid crystalline moieties will be the center of focus in this dissertation in chapter 2, chapter 4 and part of chapter 7 due to formation of hierarchical structures as a result of two competing processes: (a) microphase separation by the copolymer superstructure and (b) orientational ordering by liquid crystalline mesogens. This supramolecular cooperative assembly leads into a well-defined interface with liquid crystalline ordering in the range of 3 -10nm nanostructures and block microphase segregation of 10- 100nm microstructures. The first part of this dissertation focuses on the understanding of liquid crystalline brush-like block copolymers self-assembly, phase behavior and morphology as a function of copolymer composition and molecular weight. Here, I describe the synthesis and characterization of norbornene functionalized side chain liquid crystalline brush-like block copolymers, where one of the blocks comprises of cyanobiphenyl liquid crystalline mesogens with twelve methylene spacer and the other semi-crystalline polylactide (PLA) side chains. The self-assembly of these LC block copolymers into liquid crystalline mesophase provides the handle for magnetic alignment of the formed LCBBCs superstructures (chapter 7). The displayed morphologies such as hexagonally packed PLA cylinders in the LC matrix is put into use in the creation of functional nanoporous membranes for water purification and heavy metal sequestering (chapter 3). The high molecular weight of this LCBBCs assemble into photonic crystals of large domain sizes with different optical properties (chapter 4). In the second part of the dissertation we explore harnessing of stimuli responsive functional cholesteric random copolymers for multifunctional elastomeric platform and optical materials that cover a wide range from visible to near infrared (NIR) of electromagnetic spectrum. Overall, understanding the structure-properties of these liquid crystalline polymers leads to various applications such as membranes for separation, optics, sensors and drug delivery.
Download or read book Molecular Engineering of Hybrid Liquid Crystalline Brush like Block Copolymers Hierarchical Self assembly and Application in Photonics written by Lalit H. Mahajan and published by . This book was released on 2018 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Manipulating molecular and supramolecular cooperative interactions to introduce another level of assembly along with block copolymer superstructures has been an important area of research resulting in materials with multiple functionalities. With the aim of attaining hierarchical structures and stimuli responsive multi-functional materials, we introduce a molecularly designed architecture, Liquid Crystalline Brush-like Block Copolymers (LCBBCs), where polymer scaffolds comprising side chain liquid crystalline moieties and brush-like semicrystalline side chains within block or random architecture are introduced. Combination of two architectures can bring the unique conjunction of properties such as i) liquid crystalline order and its stimuli responsive function (magnetic, thermal, light and mechanical stimuli responsive) on the macroscopic scale ii) larger domain sizes (> 100 nm) and faster assembly dynamics of brush-like side chains iii) proximity of order-disorder transition temperature (TODT) and liquid crystalline transition temperature (Tcl) to aid in directed hierarchical self-assembly. This dissertation focuses on the 1) fundamental understanding of LCBBC self-assembly and phase behavior as a function of composition and molecular weight 2) harnessing stimuli responsive functional properties of cholesteric random copolymeric version of the same architecture to obtain multifunctional photonic elastomeric platform. In first part of dissertation, I describe molecular design-synthesis and characterization of LCBBC architecture comprising norbornene functionalized a) cyanobiphenyl liquid crystalline mesogens with twelve methylene spacer b) semi-crystalline polylactide (PLA) side chains. Morphological variety as a function of composition and dependence of domain spacing on the overall molecular weight is discussed to systematically understand the phase behavior. This architecture exhibits morphology analogous to linear-side chain LC block copolymers and perhaps some characteristics of bottlebrush architecture yielding > 100 nm domain sizes at higher Mn. In second part, I describe the molecular design-synthesis and characterization of cholesteric random terpolymer architecture to obtain elastomeric photonic platform with shape memory properties. Terpolymer scaffold self-assembles to give a hierarchical structure containing helical cholesteric mesogens along with amorphous microphase segregated domains of PEG brush-like side chains. Synergistic assembly of achiral co-monomers along with cholesteric helices yields tunable photonic reflections as a function of composition. Two-way crosslinking strategy is utilized to obtain patternable elastomeric platform with tunable photonic properties.
Download or read book Liquid Crystal Polymers written by D. Coates and published by iSmithers Rapra Publishing. This book was released on 2000 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid crystal polymers (LCPs) have a wide range of uses, from strong engineering plastics to delicate gels for use in liquid crystal (LC) displays. For this reason, it is essential reading for materials scientists, engineers or technologists in industry, as well as research laboratories or academia. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.
Download or read book Molecular Engineering of Side Chain Liquid Crystalline Polymers written by and published by . This book was released on 1992 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter discusses the molecular engineering of side chain liquid crystalline polymers mainly by living polymerization reactions. According to thermodynamic schemes, the polymer effect through its molecular weight and backbone flexibility can provide an overall change of entropy of the system. Consequently it can transform virtual mesophases into monotropic and enantiotropic mesophases. The control of molecular weight provided by living cationic polymerization of mesogenic vinyl ethers can be used successfully to tailor-make phase transitions like smectic A (SA), nematic (n) and re-entrant nematic (nre) in side chain liquid crystalline polymers and copolymers. Some additional examples of molecular engineering of side chain liquid crystalline polymers containing crown ethers and polypodants and self-assemblying side Chain liquid crystalline polymers are presented.
Download or read book Liquid Crystalline Polymers written by Vijay Kumar Thakur and published by Springer. This book was released on 2015-11-16 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces anisotropic innovations in liquid crystalline polymers as well as new nanocomposite materials and testing techniques. The authors detail the newest discoveries of material properties, material types and phases, and material characterization. This interdisciplinary work creates valuable links that strengthen the approach to the evolving field of liquid crystalline polymers/ materials.
Download or read book Hydrogen bonded Side Chain Liquid Crystalline Block Copolymer written by Chi-Yang Chao and published by . This book was released on 2003 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Liquid Crystalline Polymers written by Vijay Kumar Thakur and published by Springer. This book was released on 2015-08-25 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces various applications of liquid crystalline polymers as the emerging new class of high performance novel materials. The authors detail the advantageous properties of these LCs including optical anisotropic, transparency and easy control over structure. This interdisciplinary work includes valuable input from international projects with special focus on the use of liquid crystalline polymers and/or nanocomposites.
Download or read book Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization 20 Synthesis and Characterization of Binary Copolymers of 11 4 Cyano 4 biphenyl Oxy undecanyl Vinyl Ether with N Butyl Vinyl Ether and of 2 4 Cyano 4 biphenyl oxy ethyl Vinyl Ether with N Butyl Vinyl Ether written by and published by . This book was released on 1992 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Copolymerization represents the simplest synthetic technique which can be used to tailor make phase transitions of both main chain and side chain liquid crystalline polymers. Indeed, copolymerization was frequently employed to manipulate the phase transitions of side chain liquid crystalline polymers. However, most of the results reported in the literature can be considered only in a qualitative way, since there are only very few cases in which information about both copolymer composition and molecular weight are available. A general classification of side chain liquid crystalline copolymers was recently discussed in a review article. There are two main classes of side chain liquid crystalline copolymers. The first one refers to copolymers containing pairs of structural units with and without mesogenic units. The second class refers to copolymers based on pairs of structural units containing mesogenic units in each structural unit.
Download or read book Liquid crystalline Polymers written by American Chemical Society. Meeting and published by . This book was released on 1990 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume explores the creation, study, and processing of new liquid-crystalline polymers. It covers not only the chemistry of liquid-crystalline polymers, but also the physics and engineering aspects of these materials. A wide range of topics is covered, including syntheses of main-chain and side-chain LCPs, structural characterization of LP, rheology and processing, and applications such a electro-optics and "self-reinforcing" blends. This book presents a broad view of the direction of LCP research in both industry and academe.
Download or read book Molecular Engineering of Liquid Crystal Polymers by Living Polymerization 14 Synthesis and Characterization of Binary Copolymers of Omega 4 Cyano 4 Biphenyl oxyAlkyl Vinyl Ethers Containing Undecanyl and Hexyl Pentyl and Propyl and Undecanyl and Propyl Pairs of Alkyl Groups written by and published by . This book was released on 1991 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Copolymerization represents the simplest synthetic technique which can be used to tailor make phase transitions of both main chain and side chain liquid crystalline polymers. Indeed, copolymerization was frequently employed to manipulate the phase transitions of side chain liquid crystalline polymers. However, most of the results reported in the literature can be considered only in a qualitative way, since there are only very few cases in which information about both copolymer composition and molecular weight are available. A general classification of side chain liquid crystalline copolymers was recently discussed in a review article. There are two main classes of side chain liquid crystalline copolymers. The first one refers to copolymers containing pairs of structural units with and without mesogenic units. This class of copolymers was extensively investigated. The second class refers to copolymers based on pairs of structural units containing mesogenic units in each one.
Download or read book Molecular Engineering of Liquid Crystalline Polymers written by and published by . This book was released on 1992 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter reviews the molecular engineering of main chain and side chain liquid crystalline polymers. Several factors influencing the phase transitions of liquid crystalline polymers are critically discussed. These include thermodynamics of phase transitions, isomorphism of liquid crystals, rigidity of rod-like mesogens and chemical heterogeneity of main chain liquid crystalline copolymers. The use of polyetherification and copolyetherification and of living cationic polymerization and copolymerization in the manipulation of phase transitions of liquid crystalline polymers is extensively discussed. This review also discusses several novel architectures such as liquid crystalline dendrimers and cyclic oligomers, liquid crystalline polymers containing crown ethers and polypodants, electron donor-acceptor complexes of discotic liquid crystalline polymers, as well as, self-assemblying supramolecular liquid crystalline polymers.
Download or read book Molecular Engineering of Side Chain Liquid Crystalline Polymers Exhibiting a Chiral Smectic C Phase written by Qiang Zheng and published by . This book was released on 1994 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Liquid Crystalline Polymer Systems written by Avraam I. Isayev and published by . This book was released on 1996 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive report on the synthesis, structure, rheology, processing, performance, and applications of liquid-crystalline polymers (LCPs). Discusses self-reinforced composites prepared through the melt processing of thermoplastics and thermotropic LCPs. Addresses current research efforts in making polymer-dispersed liquid crystals. Reports recent studies on the structure and phase behavior of mesophases. Describes the synthesis and properties of new main-chain and side-chain liquid-crystalline block copolymers, mesogen-jacketed LCPs, and liquid-crystalline thermosets.
Download or read book Molecular Engineering of Side Chain Liquid Crystallinepolymers written by Case Western Reserve University, Cleveland, OH. and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Engineering of Liquid Crystal Polymers by Living Polymerization 15 Molecular Design of Reentrant Nematic Mesophases in Binary Copolymers of Omega 4 cyano 4 biphenyl oxy Alkyl Vinyl Ethers written by V. Percec and published by . This book was released on 1991 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reentrant nematic phase was discovered in 1975 in low molar mass liquid crystals. Since then it received substantial theoretical and experimental interest. The first side chain liquid crystalline polymer exhibiting a nre phase was reported in 1986. This polymer was based on a polyacrylate backbone, six methylenic units in the flexible spacer, and 4-cyano-4'-oxybiphenyl side groups. In the mean time, several other polyacrylates containing mesogenic units with cyano groups and spacer lengths with five or six atoms were reported to exhibit the unusual i-n-SAd-nre sequence. So far, there are two copolymerization experiments with a monomer whose polymer exhibits a nre phase and a monomer whose polymer exhibits a n or SA mesophase.
Download or read book Order and Interplay in Side Chain Liquid Crystalline Block Copolymers written by Paula T. Hammond and published by . This book was released on 1998 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
