Download or read book Fundamental Studies of Polyelectrolyte Multilayer Films written by Adam John Nolte and published by . This book was released on 2007 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyelectrolyte multilayers (PEMs) are a versatile type of thin film that is created via layer-by-layer assembly of positively and negatively charged polymers from aqueous solutions. Precise control of the PEM thickness, chemical functionality, and molecular architecture is made possible by changing the polyelectrolytes and assembly conditions during film growth, allowing films to be designed with properties suitable for a given application. This thesis elucidates the intra-film structure and interactions of PEMs through the use of optical, mechanical, and chemical techniques. PEM rugate filters, wherein the refractive index varies through the depth of the film in a continuous, periodic fashion, were constructed by confining silver nanoparticle growth to layers of nanometer-scale thickness. The ability to construct such structures is shown to be dependent on the ability to precisely control the concentration of metal-binding carboxylic acid groups throughout the depth of the film. Software to enable the computation design and optical simulation of these and similar structures was developed.

Download or read book Multilayer Thin Films written by Gero Decher and published by John Wiley & Sons. This book was released on 2012-06-11 with total page 1157 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second, comprehensive edition of the pioneering book in this fi eld has been completely revised and extended, now stretching to two volumes. The result is a comprehensive summary of layer-by-layer assembled, truly hybrid nanomaterials and thin fi lms, covering organic, inorganic, colloidal, macromolecular, and biological components, as well as the assembly of nanoscale fi lms derived from them on surfaces. These two volumes are essential for anyone working in the field, as well as scientists and researchers active in materials development, who needs the key knowledge provided herein for linking the field of molecular self-assembly with the bio- and materials sciences.

Download or read book Fundamental Studies of PH sensitivity in Polyelectrolyte Multilayers written by Jeeyoung Choi and published by . This book was released on 2004 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Specifically, by using a transmission FT-IR analysis on dried films, the threshold of the charge density where the resulting layer thickness exhibits a sudden incremental change due to a different chain conformation and amount of the adsorbed molecules in the multilayers was identified. Also, the pKa of PAA was revealed to shift by choice of co-assembled polycations within the multilayers, which was expanded to investigation of applications in in-situ synthesis of silver nanoparticles and pH-induced morphological transformation in weak polyelectrolyte multilayers.

Download or read book Multilayer Thin Films written by Gero Decher and published by Wiley-VCH. This book was released on 2003-03-07 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyelectrolyte multilayers, an Overview; Fundamentals of polyelectrolyte complexes in solution and the bulk; Polyelectrolyte adsorption and multilayer formation; Charge balance and transport in polyelectrolyte multilayers; Ph- controlled fabrication of polyelectrolyte multilayers: assembly and applications; Recent progress in the surface sol-gel process and protein multilayers; Internally structured polyelectrolyte multilayers; Layer-by-layer assembly of nanoparticles and nanocolloids: intermolecular interactions, structure and materials perspectives; Layer-by-layer self assembled polyelectrolytes and nanoplatelets; Chemistry directed deposition via electrostatic and secondary interactions: a nonlithographic approach to patterned polyelectrolyte multilayer systems; Layered nanoarchitetures based on electro and photo active building blocks: Coated colloids; Smart capsules; Multilayers on solid planar substrates: from structure to function; Functional layer-by-layer assemblies with photo and electrochemical response and selective transport of small molecules and ions; self-assembled and characterization of electro optic materials; Controlling the ion permeability of layered polyelectrolyte films and membranes.

Download or read book Light Emitting Characteristics and Dielectric Properties of Polyelectrolyte Multilayer Thin Films written by Michael Frederick Durstock and published by . This book was released on 1999 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physical and Optical Properties of Weakly Charged Polyelectrolyte Multilayer Films by Ozzy Mermut written by Ozzy Mermut and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Thin multilayer films were prepared through layer-by-layer adsorption of oppositely charged polyelectrolytes in aqueous media using a recently established electrostatic self-assembly approach. The adsorbing polyelectrolytes can be classified as either weak or strong based on their level of dissociation in solution. The density of charge in weakly charged polyelectrolytes, unlike in strongly charged ones, can be controlled by adjusting the solution pH about the value of its dissociation constant. At the onset of this dissertation, there were some fundamental and unresolved questions regarding assembly mechanisms, kinetics, and internal structures of the layers in polyelectrolyte multilayer films (PEMs). The studies here examine how varying the level of dissociation of polyelectrolytes in solution influences the kinetics of assembly, and adsorption behavior, as well as some structural, mechanical, and optical properties of PEMs. Using mainly ellipsometry, fluorescence, UV-vis spectrophotometry, and atomic force microscopy (used as a nanoindentation tool), the following investigations of weakly charged polyelectrolytes in multilayer assemblies were performed:" --

Download or read book Ion and Electron Transport in Polyelectrolyte Multilayers written by Samir Abou Shaheen and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polyelectrolytes are charged polymers, widely spread in nature and industry. The spontaneous association between two oppositely charged polyelectrolytes in solution yields a compact and versatile material called a polyelectrolyte complex. Polycations and polyanions can also form thin films or polyelectrolyte multilayers when they are alternately deposited on a substrate. These interesting macromolecules have been integrated into a long list of applications including fuel cells, electronics and membranes for separation. Information on the interactions and dynamics of species across polyelectrolyte composites is highly desirable to understand the performance of these materials and enhance the aspects of their applications. This dissertation focuses on probing ion, water and electron transport across a polyelectrolyte complex and investigating the interaction between a polyelectrolyte and metal surfaces. The work can be divided into three main parts: In the first part, the response of water and ions in a hydrated polyelectrolyte complex made of poly(diallyldimethylammonium), PDADMA, and poly(styrene sulfonate), PSS, were evaluated as a function of temperature. The glass transition temperature, Tg, at which the material softens was determined using rheology. The behavior of water diffusion coefficient versus temperature was monitored using pulse field gradient NMR. No change in the diffusion response was detected as the material went through Tg. Similar observation was found for the transport of small monovalent ions, such as Na+ and Cl-, which was measured using variable temperature ionic conductivity. In contrast, flux measurements on a rotating disk electrode revealed a transition point for the diffusion versus temperature of triple-charged ions, ferricyanide and ruthenium hexamine. These responses were interpreted to show the cooperative segmental mobility near the glass transition temperature. In the second part, the polyelectrolyte multilayer system made of PDADMA and PSS was also employed to produce pinhole-free ultrathin films and a radiolabeling approach was developed to determine their exact thicknesses. Electrochemical methods were used to assess electron transport from ferrocyanide redox ion to a platinum rotating disk electrode across the polymeric barriers. It was shown that even the thinnest film made of one bilayer (about 1 nm thick) provides significant blocking of electron transfer from ferrocyanide in solution to the electrode and a complete insulating film could be formed from six additional layers (9 nm). Over the 1-9 nm range, a weak current-distance dependence suggested a hopping electron transport mechanism. The classical Butler-Volmer description, which shows the current-voltage dependence, for charge transfer kinetics was modified to produce a consistent model for multi-step hopping transport through the multilayer films. Studies of polyelectrolyte interactions and the transport rate of species in polyelectrolyte complexes are fundamental to understand the often-perplexing behavior of these materials and improve their performance in the wide array of energy and separation applications. In the final part, the pairing strength between a polyelectrolyte and metal surfaces was examined. Fractional precipitation of poly(4-vinylpyridine) was used to obtain narrow molecular weight fractions. The fractions were methylated using iodomethane and characterized using NMR, FTIR and size-exclusion chromatography. One fraction was labeled with 14C radionuclide and the interaction between methylated poly(4-vinylpyridine) and metal oxide powders was monitored as a function of ionic strength using radiocounting. Metal oxides interacted differently and were divided into 3 categories: classical desorbing, peak-less desorbing and non-adsorbing. An interaction scale was set based on the cut-off salt concentration.

Download or read book Self assembly Stability Studies and Computer Modeling of Ultra Thin Protein polyelectrolyte Multilayer Films written by Venkateswarlu Panchagnula and published by . This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamental and Applied Aspects of Chemically Modified Surfaces written by J P Blitz and published by Elsevier. This book was released on 1999-01-01 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of chemically modified particle surfaces has seen many significant developments. This text covers analytical and synthetic techniques for the development and understanding of these surfaces. Encompassing subjects including self-assembled monolayers, scanning probe microscopies, combinatorial synthetic techniques, plasma polymerizations and molecular modelling of modified surfaces, the book provides a snap-shot of concepts and tools.

Download or read book Polyelectrolyte Multilayer Films for Ion Separation and Water Purification written by Maneesha Adusumilli and published by . This book was released on 2010 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook Of Nanobiomedical Research Fundamentals Applications And Recent Developments In 4 Volumes written by Vladimir P Torchilin and published by World Scientific. This book was released on 2014-08-18 with total page 2348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of 4 volumes containing about 70 chapters covering all the major aspects of the growing area of nanomedicine. Leading scientists from 15 countries cover all major areas of nanobiomedical research — materials for nanomedicine, application of nanomedicine in therapy of various diseases, use of nanomedicines for diagnostic purposes, technology of nanomedicines, and new trends in nanobiomedical research.This is the first detailed handbook specifically addressing various aspects of nanobiomedicine. Readers are treated to cutting-edge research and the newest data from leading researchers in this area.

Download or read book Polyelectrolyte Multilayer Films Containing Nanocrystalline Cellulose written by Emily D. Cranston and published by . This book was released on 2008 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adhesive Properties of Wet Polyelectrolyte Multilayer Films and Electrophoretic Deposition of Polyelectrolyte Complexes written by Chao Li and published by . This book was released on 2016 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Weak polyelectrolyte multilayers prepared by using layer-by-layer (LbL) technique are known to become sticky upon contact with water and behave as a viscoelastic fluid, but the full extent of this wet adhesive property is not fully understood. In this study, the wet adhesive performance of polyelectrolyte multilayers consisting of branched poly(ethylene imine) and poly(acrylic acid) under controlled conditions was investigated by using a 90° peel test. The peel force is highest under neutral condition, and it decreases in acidic/basic environment. The addition of metal ions changes the peel force, either increasing it or decreasing it based on the nature of the metal ion. Addition of Cu2+ stiffens multilayers, preventing multilayers from acting as an effective wet adhesive. The films are also characterized with zeta potential and shear rheometry, and the adhesiveness can be recovered by rewetting for at least 5 times. This polyelectrolyte based wet adhesive can be adhered to soft, wet surfaces like biological tissues such as liver. These multilayer films in this work show wet adhesive properties, however, the layer by layer technique used to fabricate these films requires several steps and take a long time. Therefore, new methods are needed to make these thin films. Spin-assisted LbL assembly, spray-assisted LbL assembly and electric field-assisted LbL assembly are widely studied because they are simple and time-saving. Electric field-assisted LbL assembly has been gaining an increasing interest. One option for realizing this may be the electrophoretic deposition of weak polyelectrolyte complexes, made by mixing polyelectrolytes of opposite charge together, has not been studied yet. Therefore, electrodeposition of polyelectrolyte complexes under different conditions (i.e. pH, ratio of polycation and polyanion, concentration of polyelectrolyte complexes, concentration of salt and type of electric field) was investigated in this work. Polyelectrolyte complexes at moderate pH values and at the ratio of polycation and polyanion at 20 shows highest electrophoretic mobility. The thickness of polyelectrolyte complex film decreases with decreasing the concentration of polyelectrolyte complexes while the thickness increases when a proper amount of salt is added during preparing polyelectrolyte complexes. Under controlling pulse current at 10mA, a thicker film can be achieved but the surface is rougher compared with one prepared by using pulse potential at 10V. This work provides insight into both the wet adhesive properties of polyelectrolyte multilayers and electrophoretic deposition of polyelectrolyte complexes.

Download or read book Glycopolymers Polyelectrolyte Multilayers for Biomedical Applications written by and published by Scholar Press. This book was released on 2018-01-16 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theoretical background of this work is concerning with the drug loaded polyelectrolyte multilayers (PEM) modified by the host-guest interaction of biocompatible hyperbranched core-shell glycopolymers. The glycopolymer in this work is the hyperbranched polyethyleneimine that was modified with maltose moieties using reductive amination. Thus, the use of glycohyperbranched polymers for drug delivery would allow the avoid naturally occurring drug resistance due to decreased transporter activity. Concerning preparative method, PEM was fabricated using layer-by-layer (LbL) processes involve the sequential deposition of two polyions that physically bond together. Control was taken on the stoichiometric ratio related to cationic and anionic repeating units, which was chosen close to zero for the final applied PEM. Concerning analytical methods, a couple of physical-chemical methods were applied to characterize colloid stability, adhesiveness, drug loading and release of fabricated PEM. In conclusion, a highly sable and sustainable PEM coats on a surface of an activated solid substrate has been fabricated with an efficient ability to recycle the charged molecule for more than 24 times.

Download or read book Novel Methods of Loading and Releasing Small Molecules in Polyelectrolyte Multilayer Films written by Anita Juyin Chung and published by . This book was released on 2001 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Surface and Interfacial Forces From Fundamentals to Applications written by Günter Auernhammer and published by Springer. This book was released on 2008-08-29 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: © Springer-Verlag 2008 rd 43 Biennial Meeting of the German Colloid Society rd This volume containsselected paperspresented at the 43 Biennial Meeting of the German Colloid Society held at the Schloß Waldthausen near Mainz, October 8–10, 2007. The meeting’s emphasis was given to “Surface and Interfacial Forces – From Fundamentals to Applications” but also provided a general overview on current aspects of colloid and polymer science in fundamental research and applications. The contributions in this volume are representative of the richness of research topics in colloid and polymer science. They cover a broad eld including the application of scanning probe techniques to colloid and interface science, surface induced ordering, novel developments in amphiphilic systems as well as the synthesis and applications of nano-colloids. The meeting brought together people from different elds of colloid, polymer, and materials science and provided the platform for dialogue between scientists from universities, industry, and research institutions.

Download or read book Preparation Characterization and Application of PH responsive Polyelectrolyte Multilayer Films written by Susan Elizabeth Burke and published by . This book was released on 2004 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The study of the acid-base chemistry in weak polyelectrolyte multilayer films was extended to a more complex biopolymer combination of poly(L-lysine) and hyaluronic acid. These polymers are able to adopt secondary conformational ordering in the form of alpha-helices and beta-sheets. The acid-base equilibria of the polyelectrolytes were investigated as a function of solution pH and the total number of layers in the film. These results were correlated with those obtained from the study of some of the surface and bulk properties of the films such as surface wettability, friction, film thickness, and the degree of film swelling." --