Download or read book Patterning Surfaces Using Block Copolymer Polymer Thin Films and Polymer Brushes Synthesized by a Light Mediated Controlled Radical Polymerization Technique written by Justin Ernest Poelma and published by . This book was released on 2014 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric materials are ideal for modifying the properties of a wide range of surfaces due to their structural and chemical versatility. This dissertation describes the synthesis and utility of block copolymers and polymer brushes for patterning surfaces. The effect of a cyclic molecular architecture on feature size in phase separated block copolymer thin films is discussed, as well as the synthesis of acid-cleavable block copolymers for the fabrication of highly ordered nanoporous polymer thin films. In addition to polymers synthesized in solution for deposition onto surfaces, the synthesis of polymer brushes by surface-initiated polymerizations was also studied. A new light-mediated polymerization technique catalyzed by Ir(ppy)3 was employed as the surface-initiated polymerization technique. This polymerization is highly responsive to visible light and can be used to readily access patterns of polymer brushes. Using light as an external stimulus for brush growth or functionalization by a light-mediated atom transfer radical addition reaction, the molecular weight, architecture, grafting density, and chemical functionality of polymer brushes could be spatially controlled on surfaces. Finally, the synthesis of polymers by the Ir(ppy)3-catalyzed polymerization in solution was improved by utilizing a continuous flow reactor.

Download or read book Patterning and Characterization Approaches of Polymer Thin Films written by Marvin Young Paik and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers have been used in thin film coatings as a way to produce tailor made surfaces. These thin films have been explored for use in a variety of applications to produce antifouling coatings, corrosion resistant coatings, biocompatible surfaces, and biomedical devices. Polymer brushes, polymer chains tethered to a substrate or surface, synthesized by surface-initiated polymerization have gained significant attention in recent years. As brushes offer a new pathway towards the preparation of functional surfaces and offer long term stability, even in adverse environments, they are attractive for use as high-tech coatings. Patterned polymer thin films have also seen growing interest for various applications. This dissertation will focus on the top-down direct patterning of polymer brushes and the bottom-up self-assembly of block copolymer thin films. A new approach to creating patterned polymer brushes is highlighted, which is a simpler approach than what is conventionally done. Various polymer brushes were patterned directly using electron beam lithography to create high resolution patterned polymer brushes in a single step. This method was then used to demonstrate the unique ability to create sub-surface patterns within the brush. Additionally, direct patterning was used to create high resolution patterned binary polymer brushes of PMMA and PEGMA. With this binary patterned surface, a surface that responds to its local environment was created. This thesis also details characterization techniques used in probing polymer thin films to better understand how to improve block copolymer self-assembly. By using a powerful technique called grazing incidence small angle X-ray scattering (GISAXS) on solvent vapor annealed block copolymer thin films while monitoring the solvent vapor swollen film thickness and controlling the film swelling with a nitrogen counterflow, the work presented demonstrates how to accurately determine the processing conditions necessary for the annealing process to take place. This process also provides information as to what changes are occurring during the annealing process. Another characterization technique known as near edge X-ray absorption fine structure (NEXAFS) is also highlighted. A more exact calculation of the electron escape depth (EED) for NEXAFS is done using polymer brushes as the calibration sample. With this information, we can do composition depth profiling on our polymer thin films to identify what is at the surface.

Download or read book Surface Modification with Polymer Brushes Via Light mediated Polymerizations written by Mingxiao Li and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer brushes, thin polymer coatings consisting of polymer chains that are tethered with one chain end to a surface, have drawn extensive interest in the field of surface modification. The chemical bonding between polymer and substrate allows unique properties such as chemical resistance and stimuli responsiveness. Over the past decade, numerous new chemistry platforms have been established to synthesize polymer brushes with a variety of conformations, such as diblock copolymer brushes and mixed polymer brushes. Although various applications have been demonstrated, efforts to allow industrial scale-up are still required. This dissertation focuses on developing new chemistry platforms to allow more facile and eco-friendly chemistry for polymer brush manufacturing. Surface-initiated photoinduced electron transfer -- reversible addition-fragmentation chain transfer polymerization (SI-PET-RAFT) was introduced as a novel light-mediated polymerization technique with high oxygen tolerance under a wide wavelength range of visible light. The modularity and versatility of SI-PET-RAFT was highlighted through significant flexibility with respect to the choice of monomer, light source, wavelength, and photoredox catalyst. The reproducibility of polymer brush synthesis is also interrogated. Experiments compared the stability of initiating monolayers for surface-initiated (SI) reversible addition-fragmentation chain transfer polymerization (SI-RAFT) and SI atom transfer radical polymerization (SI-ATRP). Initiator-functionalized substrates were stored under various conditions and grafting densities of the resulting polymer brush films were determined via in situ ellipsometry. Decomposition of one of the examined SI-RAFT initiators resulted in limited reproducibility for polymer brush surface modification. In contrast, initiators for SI-ATRP showed excellent stability and reproducibility. While both techniques bring inherent benefits and limitations, the described findings will help scientists choose the most efficient technique for their goals in chemical and topographical surface modification. Studies on developing synthetic platforms for mixed polymer brushes are also provided. Two different pathways, sequential SI-RAFT/SI-ATRP and sequential dual SI-PET-RAFT, were attempted due to their highly versatile monomer choices. Optimizations on each polymerization and selective chain end passivation were successfully performed. Although there still lacked direct evidence in the formation of mixed polymer brushes, the co-existence of two polymers was confirmed by X-ray photoelectron spectroscopy (XPS). Current challenges and corresponding future works are also discussed. Finally, resonance soft X-ray reflectivity (RSoXR) is introduced as a novel characterization technique to probe vertical distribution of polymer brushes. Reflectance data of homopolymer brushes, diblock copolymer brushes, spin-coated bilayer films at carbon K-edge were investigated. The depth profiles obtained via RSoXR were in agreement with results from variable angle spectroscopic ellipsometry (VASE). Both techniques revealed a rougher polymer-polymer interface in diblock copolymer brushes than in spin-coated bilayer films.

Download or read book Nitroxide Mediated Polymerization written by Didier Gigmes and published by Royal Society of Chemistry. This book was released on 2016 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book dedicated to nitroxide-mediated polymerization and covers the history and development of NMP, as well as current techniques of academic and industrial interest.

Download or read book High Resolution Patterning of Polymer Thin Films for Nanotechnology Applications written by Abhinav Rastogi and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to pattern functional polymers at different length scales is important for the advancement of modern science and technology. This dissertation mainly describes the work done on the high resolution patterning of polymer thin films that have a variety of potential uses. The nanoscale patterning of spun-coated polar polymers was demonstrated using environmentally benign supercritical carbon dioxide (scCO2) as a processing solvent. The use of scCO2 as a processing solvent has several technical advantages that help resolve some of the key problems faced in lithography. In addition, it helps reduce the energy and resource usage that can negatively affect the environment. scCO2 is generally a poor solvent for high molecular weight polymers that are used as standard photoresists. Chapter 2 describes a series of fluorinated quaternary ammonium salts that were synthesized and used as CO2 compatible additives to aid the dissolution of polar polymer photoresists in scCO2. Using these dissolution aids, patterns as small as 100 nm lines were obtained with scCO2 development. Chapters 3 and 4 focus on the patterning of high-tech thin polymer films referred to as polymer brushes. In these films the polymer chains are covalently attached to a surface. A direct method of patterning polymer brushes in a single step using electron beam lithography has been described. Polymer brushes of different structures such as poly(methyl methacrylate) (PMMA) brushes , poly(2-hydroxyethyl methacrylate) (PHEMA) brushes, poly(isobutyl methacrylate) (PIBMA) brushes, poly(neopentyl methacrylate) (PNPMA) brushes and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) brushes were grown via atom transfer radical polymerization. These brushes were directly patterned using e-beam and their sensitivity to e-beam patterning has been compared and explained. This direct patterning approach produced polymer brush patterns down to 50 nm lines. Due to the number of advantages of using scCO2 as a processing solvent, the dry development of a directly patterned low surface energy coating composed of PTFEMA brushes in scCO2 has been demonstrated in Chapter 4. Using scCO2 as a developer, patterned PTFEMA brushes with 150 nm lines were obtained. Polymer brushes have been used to prepare biocompatible surfaces with reduced non-specific adsorption. Chapter 5 describes the synthesis of a new oligo(ethylene glycol) containing ATRP intiator to prevent non-specific adsorption of biomolecules on polymer brush coated gold electrodes. The adsorption of non-specific antibodies on modified gold electrodes was studied using cyclic voltammetry. Poly(acrylic acid) brushes grown using this new ATRP initiator showed reduced nonspecific binding of the gold electrodes. There has been a continuing need for developing new medical countermeasures for emerging infectious diseases. Chapter 6 describes the role of functionalized poly(acrylic acid) brushes in the development of a biosensor based on sensitive electrochemical detection of the intrinsic catalytic activity of antibodies. Poly(acrylic acid) brushes have been functionalized with 2,4-dinitrophenyl groups (model antigen) and Ni-NTA to immobilize specific antibodies on the sensor surface. The modification of gold surfaces with polymer brushes provides a bio- and electronically compatible substrate with high density of specific haptens with reduced non-specific adsorption.

Download or read book Aqueous Lubrication Natural And Biomimetic Approaches written by Nicholas D Spencer and published by World Scientific. This book was released on 2014-03-24 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Man lubricates mostly with oil. Nature lubricates exclusively with water. Pure water is a poor lubricant, but the addition of proteins, especially glycoproteins, can modify surfaces to make them far more lubricating at slow speeds. Understanding how nature does this, and the physical structures involved, is not only important for the understanding of diseases such as osteoarthritis, but also essential for the successful application of articulating implants, such as hips and knees, as well as the development of medical devices such as catheters and contact lenses. A host of important applications of water-based lubrication are already in place in the personal care and food industries, and further industrial applications of water-based lubrication could have a significant positive impact on the environment.This book is the first of its kind. It brings together the latest research in biological and biomimetic, water-based lubrication and is authored by the world's experts in the field.

Download or read book Polymer Surfaces and Interfaces written by Manfred Stamm and published by Springer Science & Business Media. This book was released on 2008-01-26 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: In what is an extremely practical and applicable new work, experts provide concise explanations, with examples and illustrations, of the key techniques in this important field. In each case, after basic principles have been reviewed, applications of the experimental techniques are discussed and illustrated with specific examples. Scientists and engineers in research and development will benefit from an application-oriented book that helps them to find solutions to both fundamental and applied problems. They will know that the surfaces and interfaces of polymers play an important role in most of the application areas of polymers, from moulds, foils, and composites, to biomaterials and applications in micro- and nanotechnology.

Download or read book Controlled and Living Polymerizations written by Krzysztof Matyjaszewski and published by John Wiley & Sons. This book was released on 2009-09-28 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a highly prestigious and knowledgeable team of top scientists in the field, this book provides an overview of the current status of controlled/living polymerization, combining the synthetic, mechanistic and application-oriented aspects. From the contents: * Anionic Vinyl Polymerization * Carbocationic Polymerization * Radical Polymerization * Coordinative Polymerization of Olefins * Ring-Opening Polymerization of Heterocycles * Ring-Opening Metathesis Polymerization * Macromolecular Architectures * Complex Functional Macromolecules * Synthesis of Block and Graft Copolymers * Bulk and Solution Structures of Block Copolymers * Industrial Applications While some of the material is based on chapters taken from the four-volume work "Macromolecular Engineering", it is completely updated and rewritten to reflect the focus of this monograph. Must-have knowledge for polymer and organic chemists, plastics technologists, materials scientists and chemical engineers.

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 Biomimetic Polymers written by C.G. Gebelein and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: The term biomimetic is comparatively new on the chemical scene, but the concept has been utilized by chemists for many years. Furthermore, the basic idea of making a synthetic material that can imitate the func tions of natural materials probably could be traced back into antiquity. From the dawn of creation, people have probably attempted to duplicate or modify the activities of the natural world. (One can even find allusions to these attempts in the Bible; e. g. , Genesis 30. ) The term "mimetic" means to imitate or mimic. The word "mimic" means to copy closely, or to imitate accurately. Biomimetic, which has not yet entered most dictionaries, means to imitate or mimic some specific bio logical function. Usually, the objective of biomimetics is to form some useful material without the need of utilizing living systems. In a simi lar manner, the term biomimetic polymers means creating synthetic poly mers which imitate the activity of natural bioactive polymers. This is a major advance in polymer chemistry because the natural bioactive polymers are the basis of life itself. Thus, biomimetic polymers imitate the life process in many ways. This present volume delineates some of the recent progress being made in this vast field of biomimetic polymers. Chemists have been making biomimetic polymers for more than fifty years, although this term wasn't used in the early investigations.

Download or read book Oxygen Tolerant Photopolymerization for Advanced Functional Surfaces written by Michele Fromel and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric surface coatings are widely employed for diverse surface modification, with numerous applications in household goods such as non-stick frying pans, as well as in specialized materials such as membranes and opto-electronics. However, common physisorbed coatings lack the durability and stimuli-responsiveness that surface-tethered polymer brush films can offer. Using surface-initiated reversible-deactivation radical polymerization (SI-RDRP) techniques such as SI reversible addition-fragmentation chain transfer (SI-RAFT) polymerization and SI atom transfer radical polymerization (SI-ATRP), both uniform and intricately patterned surface-tethered polymer brush films can be produced. The present work focuses on the development of user- and eco-friendly SI-RDRP techniques in an effort to overcome many historical limitations on the large-scale use of SI-RDRPs: oxygen-sensitivity, limited monomer and substrate scope, costly, cumbersome patterning equipment, and the need for harsh organic solvents, thermal radical initiators, or UV-light initiation. The techniques developed herein are used to fabricate both uniform and intricately patterned, highly durable polymer brush films with functional surface properties. SI photoinduced electron transfer (PET)-RAFT is introduced as an SI-RDRP with oxygen tolerance, spatiotemporal control, monomer scope including a broad range of (meth)acrylate and (meth)acrylamide monomers, and visible light mediation. Synthetic reproducibility and long-term stability of surface initiators for both SI-RAFT and SI-ATRP are then interrogated under various storage conditions. Grafting densities of the resulting polymer brush films are determined and provide insight into storage requirements for substrates containing pre-deposited surface initiator species to ensure reproducibility of subsequent polymerizations. A photolithography approach incorporating an LED digital light projector is introduced as an inexpensive, push-of-a-button method for construction of spatially and chemically patterned polymer architectures using SI-PET-RAFT polymerization under ambient conditions. To further improve user- and eco-friendliness of polymerizations and provide access to a variety of additional monomers species, SI-PET-RAFT is then translated to aqueous solutions, allowing high ionic monomer solubility and polymerization under even lower-energy visible light. The cationic, anionic, and zwitterionic polymers accessible by this method show promise as long-lasting, functional materials with excellent anti-fogging activity. Finally, substrate scope is expanded beyond silicon-based substrates to organic materials, introducing the functionalization of polycarbonate (PC) with RAFT surface initiators. This allows modification of a popular consumer plastic using aqueous SI-PET-RAFT to produce hydrophilic polymer brushes and overcome the hydrophobicity of PC, which commonly limits its applications, particularly in biomedical applications. These new procedures and technologies place both uniform and patterned polymer brush coatings on the verge of industrialization, bringing advanced materials with long-lasting performance closer to the hands of consumers.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 942 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bioinspired Materials Science and Engineering written by Guang Yang and published by John Wiley & Sons. This book was released on 2018-08-21 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: An authoritative introduction to the science and engineering of bioinspired materials Bioinspired Materials Science and Engineering offers a comprehensive view of the science and engineering of bioinspired materials and includes a discussion of biofabrication approaches and applications of bioinspired materials as they are fed back to nature in the guise of biomaterials. The authors also review some biological compounds and shows how they can be useful in the engineering of bioinspired materials. With contributions from noted experts in the field, this comprehensive resource considers biofabrication, biomacromolecules, and biomaterials. The authors illustrate the bioinspiration process from materials design and conception to application of bioinspired materials. In addition, the text presents the multidisciplinary aspect of the concept, and contains a typical example of how knowledge is acquired from nature, and how in turn this information contributes to biological sciences, with an accent on biomedical applications. This important resource: Offers an introduction to the science and engineering principles for the development of bioinspired materials Includes a summary of recent developments on biotemplated formation of inorganic materials using natural templates Illustrates the fabrication of 3D-tumor invasion models and their potential application in drug assessments Explores electroactive hydrogels based on natural polymers Contains information on turning mechanical properties of protein hydrogels for biomedical applications Written for chemists, biologists, physicists, and engineers, Bioinspired Materials Science and Engineering contains an indispensible resource for an understanding of bioinspired materials science and engineering.

Download or read book Organization and Orientation of Rod type Polymer Brushes in Different Brush Architectures Under Solvent Treatments written by Hai Quang Tran and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer brushes covalently attached to surfaces have been comprehensively studied for the last two decades since they can effectively transform surface properties for a variety of applications. However, the majority of previous studies have been focused on coil-type polymer brushes, so there is a lack of understanding in the behavior and molecular organization (e.g. conformation) of the equally important rod-type brushes when subjected to external factors such as solvent conditions or temperature. In this study, we found that for polypeptide rod-type brushes the polymer tilt angle from the surface normal changed as a function of brush thickness. Moreover, the number and nature of rod assemblies decreased while the size increased with increasing brush thickness. We showed that rod organization and orientation was strongly dependent on the conditions of a quenching process, depending on factors such as solvent miscibility and extraction rate. We also demonstrated polymer rigidity was crucial to the vertical orientation of the polypeptide. Additionally, polypeptide brushes can induce a change in liquid crystal (LC) orientation through a dispersion interaction, and the LC orientation was also proportional to the tilt of the polypeptide. Moreover, in mixed rod-coil brushes, before solvent quenching, coil brushes decreased the polypeptide tilt angle from the surface normal, resulting in a higher film thickness while after solvent quenching, coil brushes increased the number, but lowered the size of rod assemblies. We also studied nanopatterned polypeptide brushes prepared with electron beam lithography. Polypeptide brushes formed well-defined nanostructures inside pattern boundaries. Both the number of rod assemblies and brush thickness increased with pattern size. When the distance between adjacent patterns was comparable to polymer length, polymer bridges formed due to the interaction between polymer chains of adjacent patterns. The polymer bridges were alleviated by the addition of coil brushes into the otherwise empty areas. Mixed rod-coil brushes of mesogen-jacketed liquid crystalline polymer (MJLCP) and fluorinated polymer was studied. The high immiscibility between the polymers was crucial to the formation of rod assemblies whose size increased with increasing MJLCP thickness. The number of rod assemblies increased with thicker fluorinated brushes. Surface morphology can be tuned by controlling thickness of the two polymers. We also demonstrated coil brush synthesis without a typical deoxygenation step via surface initiated- single electron transfer-living radical polymerization (SI-SET-LRP). Various polymers and brush architectures could be produced with this method.

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanostructured Thin Films and Surfaces written by and published by John Wiley & Sons. This book was released on 2010-03-08 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book series Nanomaterials for the Life Sciences, provides an in-depth overview of all nanomaterial types and their uses in the life sciences. Each volume is dedicated to a specific material class and covers fundamentals, synthesis and characterization strategies, structure-property relationships and biomedical applications. The series brings nanomaterials to the Life Scientists and life science to the Materials Scientists so that synergies are seen and developed to the fullest. Written by international experts of various facets of this exciting field of research, the series is aimed at scientists of the following disciplines: biology, chemistry, materials science, physics, bioengineering, and medicine, together with cell biology, biomedical engineering, pharmaceutical chemistry, and toxicology, both in academia and fundamental research as well as in pharmaceutical companies. VOLUME 5 - Nanostructured Thin Films and Surfaces

Download or read book An Approach to Surface Modifications with Polymer Brushes Using Aqueous Synthetic Techniques and Characterization written by Roselynn Cordero and published by . This book was released on 2018 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis introduces a new emulsion polymerization technique called mini monomer encapsulated emulsion polymerization (mini ME emulsion) using activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) to form narrow dispersity poly(methyl methacrylate), PMMA and polystyrene, PS. Subsequent chapters discuss use of this method to create polymer brushes on silica nanoparticles to form "hairy" nanoparticles, and the use of polymer brushes on silica and cellulose substrates to serve as an antibody sensor. "Hairy nanoparticles" use a combination of a polymer brush and an inorganic nanoparticle core to improve the mechanical and thermal properties of a film. Mini ME emulsion polymerization was created for the controlled polymerization of PMMA and PS in an aqueous medium. By guiding reaction localization with a phase transfer agent, tetrabutylammonium bromide (TBAB) and with acetone to control their diffusion rate, continuous feeding of the reaction loci with monomer was employed to keep a constant concentration of propagating radicals. This reaction process leads to low dispersity polymers with a predetermined molecular weight in an emulsion polymerization. Once mini ME emulsion polymerization was established in aqueous media, the polymerization method was modified to grow polymer chains on a nanoparticle surface to obtain hairy nanoparticles. Within recent years, the study of polymer brushes, which is broadly defined as polymer chains bound to a surface, has enabled ground-breaking materials with tailored interfaces, finding applications in nonfouling biosurfaces and creating novel mechanical and optical nanocomposite materials. The particles were functionalized with a hydrophobic initiator to control the polymerization loci forcing initiation to occur only within the organic phase surrounding the nanoparticle and minimizing reaction in the aqueous medium. Results of the new reaction route are described. This technique was also employed to generate polymer brushes on surfaces such as those suitable for biosensing devices and is discussed. Reaction conditions and the results of preliminary testing to these new structures for antibody sensing are described. A poly(oligoethylene glycol) methacrylate (POEGMA) polymer brush, which is used to prevent non-specific adsorption of biomolecules, was grown from cellulose or silica microparticles under aqueous conditions. These brushes were then post-modified with a model antigen, dinitrophenyl (DNP) to increase the specificity of the sensor via specific antibody-antigen recognition. Preliminary results suggest that polymer brushes are needed to increase the sensitivity of the sensor by repelling molecules that would lead to a false positive result. A sensor based on the antibody catalyzed water oxidation pathway (ACWOP) eliminates the need for a secondary antibody, thus further increasing both the specificity and sensitivity of the device and is described in this thesis.