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 Molecular Engineering of Side chain Liquid Crystalline Brush Copolymers for Photonic and Nanoporous Membrane Applications written by and published by . This book was released on 2013 with total page 226 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 Self assembly of Brush Polymers written by Benjamin Ragnar Sveinbjörnsson and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique structure and properties of brush polymers have led to increased interest in them within the scientific community. This thesis describes studies on the self-assembly of these brush polymers. Chapter 2 describes a study on the rapid self-assembly of brush block copolymers into nanostructures with photonic bandgaps spanning the entire visible spectrum, from ultraviolet to near infrared. Linear relationships are observed between the peak wavelengths of reflection and polymer molecular weights. This work enables "bottom-up" fabrication of photonic crystals with application-tailored bandgaps, through synthetic control of the polymer molecular weight and the method of self-assembly. Chapter 3 details the analysis of the self-assembly of symmetrical brush block copolymers in bulk and thin films. Highly ordered lamellae with domain spacing ranging from 20 to 240 nm are obtained by varying molecular weight of the backbone. The relationship between degree of polymerization and the domain spacing is reported, and evidence is provided for how rapidly the brush block copolymers self-assemble and achieve thermodynamic equilibrium. Chapter 4 describes investigations into where morphology transitions take place as the volume fraction of each block is varied in asymmetrical brush block copolymers. Imaging techniques are used to observe a transition from lamellar to a cylindrical morphology as the volume fraction of one of the blocks exceeds 70%. It is also shown that the asymmetric brush block copolymers can be kinetically trapped into undulating lamellar structures by drop casting the samples. Chapter 5 explores the capability of macromolecules to interdigitate into densely grafted molecular brush copolymers using stereocomplex formation as a driving force. The stereocomplex formation between complementary linear polymers and brush copolymers is demonstrated, while the stereocomplex formation between complementary brush copolymers is shown to be restricted.
Download or read book Self assembly of Brush Polymers written by Benjamín Ragnar Sveinbjörnsson and published by . This book was released on 2014 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique structure and properties of brush polymers have led to increased interest in them within the scientific community. This thesis describes studies on the self-assembly of these brush polymers. Chapter 2 describes a study on the rapid self-assembly of brush block copolymers into nanostructures with photonic bandgaps spanning the entire visible spectrum, from ultraviolet to near infrared. Linear relationships are observed between the peak wavelengths of reflection and polymer molecular weights. This work enables "bottom-up" fabrication of photonic crystals with application-tailored bandgaps, through synthetic control of the polymer molecular weight and the method of self-assembly. Chapter 3 details the analysis of the self-assembly of symmetrical brush block copolymers in bulk and thin films. Highly ordered lamellae with domain spacing ranging from 20 to 240 nm are obtained by varying molecular weight of the backbone. The relationship between degree of polymerization and the domain spacing is reported, and evidence is provided for how rapidly the brush block copolymers self-assemble and achieve thermodynamic equilibrium. Chapter 4 describes investigations into where morphology transitions take place as the volume fraction of each block is varied in asymmetrical brush block copolymers. Imaging techniques are used to observe a transition from lamellar to a cylindrical morphology as the volume fraction of one of the blocks exceeds 70%. It is also shown that the asymmetric brush block copolymers can be kinetically trapped into undulating lamellar structures by drop casting the samples. Chapter 5 explores the capability of macromolecules to interdigitate into densely grafted molecular brush copolymers using stereocomplex formation as a driving force. The stereocomplex formation between complementary linear polymers and brush copolymers is demonstrated, while the stereocomplex formation between complementary brush copolymers is shown to be restricted.
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 Three dimensional Self assembly of Brush Block Copolymers to Photonic Crystals written by Melody Ann Morris and published by . This book was released on 2013 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of Ring Opening Metathesis Polymerization has allowed the world of block copolymers to expand into brush block copolymers. Brush block copolymers consist of a polymer backbone with polymeric side chains, forcing the backbone to hold a stretched conformation and giving it a worm-like shape. These brush block copolymers have a number of advantages over tradition block copolymers, including faster self-assembly behavior, larger domain sizes, and much less entanglement. This makes them an ideal candidate in the development of a bottom-up approach to forming photonic crystals. Photonic crystals are periodic nanostructures that transmit and reflect only certain wavelengths of light, forming a band gap. These are used in a number of coatings and other optical uses. One and two dimensional photonic crystals are commercially available, though are often expensive and difficult to manufacture. Previous work has focused on the creation of one dimensional photonic crystals from brush block copolymers. In this thesis, I will focus on the synthesis and characterization of asymmetric brush block copolymers for self-assembly into two and three dimensional photonic crystals. Three series of brush block copolymers were made and characterized by Gel Permeation Chromatography and Nuclear Magnetic Resonance spectroscopy. They were then made into films through compressive thermal annealing and characterized by UV-Vis Spectroscopy and Scanning Electron Microscopy. Evidence of non-lamellar structures were seen, indicating the first reported creation of two or three dimensional photonic crystals from brush block copolymers.
Download or read book Rapid Self assembly of Block Copolymers to Photonic Crystals written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The invention provides a class of copolymers having useful properties, including brush block copolymers, wedge-type block copolymers and hybrid wedge and polymer block copolymers. In an embodiment, for example, block copolymers of the invention incorporate chemically different blocks comprising polymer size chain groups and/or wedge groups that significantly inhibit chain entanglement, thereby enhancing molecular self-assembly processes for generating a range of supramolecular structures, such as periodic nanostructures and microstructures. The present invention also provides useful methods of making and using copolymers, including block copolymers.
Download or read book Liquid Crystalline Order in Polymers written by Alexandre Blumstein and published by Elsevier. This book was released on 2012-12-02 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid Crystalline Order in Polymers examines the topic of liquid crystalline order in systems containing rigid synthetic macromolecular chains. Each chapter of the book provides a review of one important area of the field. Chapter 1 discusses scattering in polymer systems with liquid crystalline order. It also introduces the field of liquid crystals. Chapter 2 treats the origin of liquid crystalline order in macromolecules by describing the in-depth study of conformation of such macromolecules in their unassociated state. The chapters that follow describe successively the liquid crystalline order in polymers with mesogenic side groups and rigid backbones, in polypeptides, and in block copolymers. Chapter 7 discusses the rheology of such systems. The last two chapters examine liquid crystalline order in biological materials and mesomorphic order in the realm of polymers with inorganic backbones. This book is intended to provide the polymer scientist, the materials scientist, and the biologist with a valuable source of information.
Download or read book Silicon Containing Hybrid Copolymers written by Chaobin He and published by John Wiley & Sons. This book was released on 2020-01-31 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combines chemistry and material science in order to provide a complete overview of the design, synthesis, and applications of organo-silica This book offers comprehensive and systematic coverage of the latest developments in functional hybrid silicon copolymers, their applications, and how they were developed in relation to previous works in the preparation of various functional groups terminated silicone materials. Silicon Containing Hybrid Copolymers begins with a chapter that introduces readers to organo-silicon materials. It then presents a chapter on reactive functionally terminated polyorganosiloxanes, and contains a section on the methods and advances of functionalized polyhedral oligomeric silsesquioxanes (POSS) and copolymers. Nanostructured self-assemblies from silicon containing hybrid copolymers are discussed?as are superhydrophobic materials derived from hybrid silicon. Other chapters examine silicone copolymers for healthcare and personal care applications; construction of organic optoelectronic materials by using polyhedral oligomeric silsesquioxanes (POSS); and 3D printing silicone materials and devices. The book also includes an overview of material toughening and fire retardancy in regards to hybrid POSS nanocomposites. This title: -Focuses on design and synthesis strategies, providing a valuable resource for researchers in academia and industry -Presents recent applications, with emphasis on the underlying strategies and the influence from previous designs, in fields such as healthcare and consumer care -Combines synthetic pathways with design specific considerations to provide the reader with greater control over the design process Silicon Containing Hybrid Copolymers is an ideal book for materials scientists, polymer chemists, and bioinorganic chemists.
Download or read book Hierarchical Ordering written by Jingbo Wang and published by . This book was released on 2012 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Amorphous crystalline Brush Block Copolymers written by Gayathri Kopanati and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Bottlebrush block copolymers are polymers with chemically distinct polymer side chains grafted onto a common backbone. The unique architecture induced properties make these materials attractive for applications such as photonic materials, stimuli responsive actuators and drug delivery vehicles to name a few. This dissertation primarily investigates the phase transitions and rheological behavior of amorphous-crystalline bottlebrush brush block copolymers and their composites. The temperature induced phase behavior is investigated using time resolved synchrotron X-ray source. Irrespective of volume fraction and backbone length, the samples display strong segregation even at high temperatures (200 °C) and there is no accessible order-disorder transition in the temperature range of 25-200 °C. The isothermal crystallization kinetics reveal a two-stage crystallization process, different than that observed in linear block copolymers. A considerable part of this dissertation is focused on the study of the effect of hydrogen bonding additives on the relaxations of brush block copolymer. The additives greatly enhance the mechanical and physical properties of the pristine polymer. The small molecules also impart a gel-like characteristic due to the formation of physically crosslinked network. Finally, the understanding of the brush block copolymer systems from the previous studies and literature is used to study the self-assembly of nanorods using brush block copolymers as templates.
Download or read book Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization 23 Synthesis and Characterization of AB Block Copolymers written by and published by . This book was released on 1992 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes the synthesis and characterization of AB block copolymers based on w-((4-cyano-4'-biphenyl)oxy)alkyl vinyl ether (6-n) with alkyl being ethyl (6-2), propyl (6-3), nonyl (6-9) and undecanyl (6-11) with 1H, 1H, 2H, 2H-perfluorodecyl vinyl ether (CF8), poly(6-n)-b-CF8)X/Y (where X/Y refers to the weight ratio of the two segments), and of 2-(4-biphenyloxy)ethyl vinyl ether (BEVE) with 1H, 1H, 2H, 2H-perfluoeodecyl vinyl ether, poly(BEVE-b- CF8)X/Y. They were prepared by living cationic polymerization and exhibit a narrow molecular weight distribution. All block copolymers display a microphase separated morphology when the A segment is in the liquid crystalline phase. Block copolymers based on 6-2, 6-3 and BEVE with CF8 exhibit a microphase separated morphology also in the melt phase of A and B block.
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 Morphology and Self assembly Behavior of Side Chain Liquid Crystalline Block Copolymers written by Eric Anton Verploegen and published by . This book was released on 2008 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: (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.
Download or read book Sensory Polymers written by José Miguel García and published by Elsevier. This book was released on 2024-08-01 with total page 878 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensory Polymers: From their Design to Practical Applications discusses recent developments in the field of sensory polymers and showcases the potential applications of these materials in food control and security, civil security, the biomedical field, environmental control and remediation, industrial control of chemicals, and more. Written by worldwide experts in the field, chapters provide in-depth knowledge on several different polymer sensors and their response to different stimuli, which makes this book a valuable resource for researchers and advanced students in polymer science, materials science, and chemistry, as well as those interested on sensing applications and chemical sensory systems, including industry R&D. Discusses the foundation of sensory polymers, from material design to development and production Explores state-of-the-art applications in environmental control, biomedicine, sensing, the chemical industry, and food science Provides perspectives and future applications of polymer chemosensors
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:
