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 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 Single Crystal Engineering of Amorphous crystalline Block Copolymers Crystallization Morphology and Applications written by Yan Chen and published by . This book was released on 2005 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Block Copolymers written by Francisco Balta Calleja and published by CRC Press. This book was released on 2000-06-09 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: A summary of block copolymer chemical structures and synthesis. It discusses physical methods of characterization such as computer simulation, microhardness, dielectric spectroscopy, thermal mechanical relaxation, ultrasonic characterization, transmission electron microscopy, X-ray scattering, and NMR, among others. It also outlines rheological and processing parameters in the multiphase polymer systems with stable microstructures.

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 New Synthetic Approach for the Liquid Crystalline Amorphous Block Copolymers written by Turgay Kaçar and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Control of Crystal Thickness and Melting Point in Crystalline Amorphous Block Copolymers written by Li-Bong Lee and published by . This book was released on 2002 with total page 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 Developments in Block Copolymer Science and Technology written by Ian W. Hamley and published by John Wiley & Sons. This book was released on 2004-07-16 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focuses on recent advances in research on block copolymers, covering chemistry (synthesis), physics (phase behaviors, rheology, modeling), and applications (melts and solutions). Written by a team of internationally respected scientists from industry and academia, this text compiles and reviews the expanse of research that has taken place over the last five years into one accessible resource. Ian Hamley is the world-leading scientist in the field of block copolymer research Presents the recent advances in the area, covering chemistry, physics and applications. Provides a broad coverage from synthesis to fundamental physics through to applications Examines the potential of block copolymers in nanotechnology as self-assembling soft materials

Download or read book Self assembly of Block Copolymers in Dilute Solution written by Kathleen A. Cogan and published by . This book was released on 1991 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Study of Onsets of Tethered Chain Overcrowding and Highly Stretched Brush Regime Via Crystalline amorphous Diblock Copolymers written by Xiaoliang Zheng and published by . This book was released on 2005 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Tethered polystryrene (PS) chains were generated using lamellar single crystals of two series of diblock copolymers, poly(ethylene oxide)-block-PS (PEO-b-PS) and poly(L-lactic acid)-block-PS (PLLA-b-PS), grown in dilute solutions of amyl acetate. By controlling the crystallization temperature (T[subscript x]) and molecular weights of the crystalline and amorphous blocks, a finely-tuned, broad coverage of reduced tethering density was achieved (up to 24). Plots of the reciprocal lamellar crystal thickness of PEO or PLLA and T[subscript x] quantitatively provided information about the additional free energy near the lamellar surfaces that is attributed to the entropic repulsion among the tethered PS chains. The onset where the tethered PS chains start to get squeezed by their neighbors in solution occurs at [reduced tethering density] ~3.7 ([reduced tethering density]*) in all the cases as evidenced by an abrupt change in the slope between (d[subscript L])−1 and T[subscript x]. This first onset is a discontinuous transition. Based on the scaling law, our experimental results could, for the first time, identify the reduced density for the onset at the highly stretched brush regime, [reduced tethering density] = 14.3 ([reduced tethering density]**). This second onset is a continuous transition."--P. iii.

Download or read book Polymer Science A Comprehensive Reference written by and published by Newnes. This book was released on 2012-12-05 with total page 7752 pages. Available in PDF, EPUB and Kindle. Book excerpt: The progress in polymer science is revealed in the chapters of Polymer Science: A Comprehensive Reference, Ten Volume Set. In Volume 1, this is reflected in the improved understanding of the properties of polymers in solution, in bulk and in confined situations such as in thin films. Volume 2 addresses new characterization techniques, such as high resolution optical microscopy, scanning probe microscopy and other procedures for surface and interface characterization. Volume 3 presents the great progress achieved in precise synthetic polymerization techniques for vinyl monomers to control macromolecular architecture: the development of metallocene and post-metallocene catalysis for olefin polymerization, new ionic polymerization procedures, and atom transfer radical polymerization, nitroxide mediated polymerization, and reversible addition-fragmentation chain transfer systems as the most often used controlled/living radical polymerization methods. Volume 4 is devoted to kinetics, mechanisms and applications of ring opening polymerization of heterocyclic monomers and cycloolefins (ROMP), as well as to various less common polymerization techniques. Polycondensation and non-chain polymerizations, including dendrimer synthesis and various "click" procedures, are covered in Volume 5. Volume 6 focuses on several aspects of controlled macromolecular architectures and soft nano-objects including hybrids and bioconjugates. Many of the achievements would have not been possible without new characterization techniques like AFM that allowed direct imaging of single molecules and nano-objects with a precision available only recently. An entirely new aspect in polymer science is based on the combination of bottom-up methods such as polymer synthesis and molecularly programmed self-assembly with top-down structuring such as lithography and surface templating, as presented in Volume 7. It encompasses polymer and nanoparticle assembly in bulk and under confined conditions or influenced by an external field, including thin films, inorganic-organic hybrids, or nanofibers. Volume 8 expands these concepts focusing on applications in advanced technologies, e.g. in electronic industry and centers on combination with top down approach and functional properties like conductivity. Another type of functionality that is of rapidly increasing importance in polymer science is introduced in volume 9. It deals with various aspects of polymers in biology and medicine, including the response of living cells and tissue to the contact with biofunctional particles and surfaces. The last volume is devoted to the scope and potential provided by environmentally benign and green polymers, as well as energy-related polymers. They discuss new technologies needed for a sustainable economy in our world of limited resources. Provides broad and in-depth coverage of all aspects of polymer science from synthesis/polymerization, properties, and characterization methods and techniques to nanostructures, sustainability and energy, and biomedical uses of polymers Provides a definitive source for those entering or researching in this area by integrating the multidisciplinary aspects of the science into one unique, up-to-date reference work Electronic version has complete cross-referencing and multi-media components Volume editors are world experts in their field (including a Nobel Prize winner)

Download or read book Single Crystal Engineering of Linear Tri block Copolymers written by Huiming Xiong and published by . This book was released on 2006 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Single crystals of poly(methyl methacrylate)-b-polystyrene-b-poly(L-lactic acid) (PMMA-b-PS-b-PLLA) triblock copolymers with different compositions have been grown in dilute solution and utilized as ideal models for the study of structures and morphologies of tethered PS-PMMA diblock copolymer chains. With control of tethering density and tethering density distribution, the diblock copolymers are found to form switchable characteristic morphologies in selective solvent treatments. A novel "onion"-like structure has been observed for the first time due to the controllable and uniform tethering density. This switching behavior has been confirmed by surface enhanced Raman spectroscopic experiments. Two series of triblock copolymers with a crystalline block in the middle, polystyrene-b-poly(ethylene oxide)-b-poly(butene oxide) (PS-b-PEO-b-PBO) and polystyrene-b-poly(ethylene oxide)-b-poly(dimethyl siloxane) (PS-b-PEO-b-PDMS) have been synthesized. Scrolled single crystals have been found which were favored with increased tethering density. The scrolling direction was found to be along the (120) plane of the PEO single lamellar crystal. Based on the curvature of scrolling, strain energy can be calculated which corresponds to the unbalanced near surface stresses caused by tethered chains on opposite folding surfaces under a mechanic equilibrium."--abstract.

Download or read book Complex Macromolecular Systems II written by Axel H. E. Müller and published by Springer Science & Business Media. This book was released on 2010-05-21 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: -Polyelectrolyte Stars and Cylindrical Brushes By Y. Xu, F. Plamper, M. Ballauff, and A. H. E. Müller -Various Aspects of the Interfacial Self-Assembly of Nanoparticles By N. Popp, S. Kutuzov, A. Böker -Holographic Gratings and Data Storage in Azobenzene-Containing Block Copolymers and Molecular Glasses By H. Audorff, K. Kreger, R. Walker, D. Haarer, L. Kador, and H.-W. Schmidt -Donor–Acceptor Block Copolymers with Nanoscale Morphology for Photovoltaic Applications By M. Sommer, S. Huettner, and M. Thelakkat -Recent Advances in the Improvement of Polymer Electret Films By D. P. Erhard, D. Lovera, C. von Salis-Soglio, R. Giesa, V. Altstädt, and H.-W. Schmidt

Download or read book Block Copolymers in Solution written by Ian W. Hamley and published by John Wiley & Sons. This book was released on 2005-09-02 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique text discusses the solution self-assembly of block copolymers and covers all aspects from basic physical chemistry to applications in soft nanotechnology. Recent advances have enabled the preparation of new materials with novel self-assembling structures, functionality and responsiveness and there have also been concomitant advances in theory and modelling. The present text covers the principles of self-assembly in both dilute and concentrated solution, for example micellization and mesophase formation, etc., in chapters 2 and 3 respectively. Chapter 4 covers polyelectrolyte block copolymers - these materials are attracting significant attention from researchers and a solid basis for understanding their physical chemistry is emerging, and this is discussed. The next chapter discusses adsorption of block copolymers from solution at liquid and solid interfaces. The concluding chapter presents a discussion of selected applications, focussing on several important new concepts. The book is aimed at researchers in polymer science as well as industrial scientists involved in the polymer and coatings industries. It will also be of interest to scientists working in soft matter self-assembly and self-organizing polymers.

Download or read book Functional Polymers written by Raja Shunmugam and published by CRC Press. This book was released on 2017-05-08 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new book covers the synthetic as well application aspects of functional polymers. It highlights modern trends in the field and showcases the recent characterization techniques that are being employed in the field of polymer science. The chapters are written by top-notch scientists who are internationally recognized in the field. The chapters will highlight the modern trend in the field.

Download or read book Controlled Living Radical Polymerization written by Krzysztof Matyjaszewski and published by OUP USA. This book was released on 2007-01-04 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The preparation and characterization of new materials with precisely controlled macromolecular dimensions, functionalities, and decomposition, as well as with well-defined topologies, is perhaps the main focus of contemporary polymer synthesis. The best control of molecular functions can be achieved in a controlled/living polymerization -- a chain growth process without chain breaking reactions. Recently, controlled/living polymerizations have extended to radical systems which are not only commercially important, but also have the largest potential due to the availability of radically polymerizable monomers, facile copolymerization and undemanding experimental conditions. Controlled Radical Polymerization will examine recent advances in mechanistic and synthetic aspects of controlled/living radical (co)polymerization systems. Not only will this book be focused on recent progress in the dynamically developing field of controlled/living radical polymerization, but it will be a sequel to the very popular ACS Symposium Series 685, 768, and 854. The book will consist of >30 chapters separated into seven subsections: Fundamentals, Mechanism of ATRP, Mechanisms of SFRP and Degenerative Transfer Processes, Controlled Architecture by CRP, Organic-inorganic Hybrids by CRP, Biomaterials by CRP and Industrial Applications. This book targets chemists and polymer scientists in academia and in industry.