Download or read book Phase Behaviour of Proteins and Colloid Polymer Mixtures written by Christoph Gögelein and published by Forschungszentrum Jülich. This book was released on 2008 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Molecular Simulation to Explore Protein and Colloidal Phase Behavior in Bulk Confinement and Mixtures written by Thomas W. Rosch and published by . This book was released on 2008 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of the ubiquity of colloidal solutions in everyday industrial applications such as papermaking and coatings there is a need to be able to efficiently design and manufacture these substances. A related issue concerns the connection between many physiological diseases and heath defects and the stability and phase behavior of certain proteins. It is imperative to understand the physical mechanisms that cause proteins to change their normal solution characteristics. To design colloidal solutions for specific applications as well as to produce preventative medicines and therapies an intimate knowledge of the connection between particle interactions and overall physical properties of the solution is needed. To probe this issue four types of systems are examined. In each system solution conditions are altered affecting the nature and strength of the particle interactions. Our goal is to understand the physics behind the evolution of fluid properties that occurs because of changes in microscopic interactions. The method we employ in this pursuit is grand canonical transition matrix Monte Carlo. We examine an embedded point charge protein model of lysozyme in bulk, mixed with polymer, as well as in confinement. We find that in bulk the model is able to capture qualitatively experimental trends for changes in critical temperature and evolution of the fluid phase diagram with changing solution conditions such as salt concentration and pH. Quantitatively the model predicts a relatively narrow coexistence curve compared to experimental values. It is found that the osmotic second virial coefficient remains relatively constant over a broad range of solutions conditions suggesting a universal magnitude of attraction needed to induce phase separation. We examine a simple system consisting of hard sphere colloids with added Gaussian core polymers. Decreasing the size of the polymers relative to colloids as well as increasing the energetic repulsion between polymers upon overlap results in an overall stabilization of the mixture. Unlike bulk solutions containing molecules of the Carlsson et al. lysozyme model, the osmotic second virial coefficient at the critical point for model colloid-polymer mixtures is not constant but depends on polymer size and interaction. Increasing polymer size or decreasing polymer repulsion results in a larger negative value. Overall the model fails to capture the experimental behavior of polymer excluded volume interactions because its inability to describe the polymers capability of deformation around the colloid. We extend our analysis to a mixture containing the embedded charge model for lysozyme and Gaussian core polymers. Overall, the system exhibited a strong dependence on pH and salt concentration that qualitatively followed experimental trends. Increase of salt concentration or decrease in protein charge decreases the number of polymers needed to induce phase separation. This trend was not sensitive to the size of the polymer relative to the protein. Finally we examine the effect surface interactions have on the phase behavior for the lysozyme model as well as a simple square well model. Both systems exhibited a distinctly non-monotonic variation of its critical temperature as a function of fluid-wall interaction strength. A maximum occurs at an intermediate strength. We introduce two metrics that enable one to predict the location of this maximum. The first is related to the contact angle a fluid makes with the confining substrate while the second is based upon virial coefficient information. Because similar trends are exhibited in both systems we believe that the results should be general in nature.

Download or read book Colloids and the Depletion Interaction written by Henk N.W. Lekkerkerker and published by Springer Science & Business Media. This book was released on 2011-05-12 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloids are submicron particles that are ubiquitous in nature (milk, clay, blood) and industrial products (paints, drilling fluids, food). In recent decades it has become clear that adding depletants such as polymers or small colloids to colloidal dispersions allows one to tune the interactions between the colloids and in this way control the stability, structure and rheological properties of colloidal dispersions. This book offers a concise introduction to the fundamentals of depletion effects and their influence on the phase behavior of colloidal dispersions. Throughout the book, conceptual explanations are accompanied by experimental and computer simulation results. From the review by Kurt Binder: "They have succeeded in writing a monograph that is a very well balanced compromise between a very pedagogic introduction, suitable for students and other newcomers, and reviews of the advanced research trends in the field. Thus each chapter contains many and up to date references, but in the initial sections of the chapters, there are suggested exercises which will help the interested reader to recapitulate the main points of the treatment and to deepen his understanding of the subject. Only elementary knowledge of statistical thermodynamics is needed as a background for understanding the derivations presented in this book; thus this text is suitable also for advanced teaching purposes, useful of courses which deal with the physics for soft condensed matter. There does not yet exist any other book with a similar scope..... The readability of this book is furthermore enhanced by a list of symbols, and index of keywords, and last not least by a large number of figures, including many pedagogic sketches which were specifically prepared for this book. Thus, this book promises to be very useful for students and related applied sciences alike." Eur. Phys. J. E (2015) 38: 73

Download or read book Phase Behavior Microstructure and Mechanics of Colloid Polymer Mixtures written by Syed Ali Shah and published by . This book was released on 2003 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polymer Mediated Phase Stability of Colloids written by Álvaro González García and published by Springer. This book was released on 2020-11-07 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloid–polymer mixtures are subject of intensive research due to their wide range of applicability, for instance in coatings and food-stuffs. This thesis constitutes a fundamental investigation towards a better control over the stability of such suspensions. Through the chapters, different key parameters governing the stability of colloid–polymer mixtures are explored. How the colloid (pigment) shape and the effective polymer-colloid affinity modulate the stability of the suspension are examples of these key parameters. Despise the mostly theoretical results presented, the thesis is written in a format accessible to a broad scientific audience. Some of the equations of state presented might of direct use to experimentalists. Furthermore, new theoretical insights about colloid–polymer mixtures are put forward. These include four-phase coexistences in effective two-component, quantification of depletant partitioning at high colloidal concentrations, multiple re-entrant phase behaviour of the colloidal fluid–solid coexistence, and a condition where polymers are neither depleted nor adsorbed from/to the colloidal surface.

Download or read book Colloids and the Depletion Interaction written by Henk N. W. Lekkerkerker and published by Springer Nature. This book was released on with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Mechanistic Understanding of the Polymer induced Phase Behavior of Colloidal scale Suspensions written by Naa Larteokor McFarlane and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The phase behavior of model polymer - colloid mixtures is measured in the "protein limit", i.e., when the radius of gyration of the polymer (R g) is greater than or approximately equal to the radius of the colloid (R) and in the "colloid limit" (R> R g). In this work, alumina-covered silica nanoparticles are mixed with poly (ethylene oxide) (PEO) or poly (vinyl pyrolidone) (PVP) at asymmetry ratios of R g /R = 0.7 and 1.8. The adsorption of the two polymers onto the cationic nanoparticles was measured using isothermal titration calorimetry (ITC), gravimetric methods, and dynamic light scattering. Addition of PEO to stable nanoparticle dispersions leads to phase separation by depletion flocculation in both deionized water and buffer solutions. The phase separation mechanism for the PVP - nanoparticle system depends on the suspension medium. In water, bridging induced separation occurs below the saturation adsorption of PVP; above surface saturation, mixing leads to depletion-induced separation. In acidic buffer, phase separation results from depletion-induced interactions. ITC measurements of the heats of adsorption unambiguously determine the effects of polymer type and added buffer solution on the stability of nanoparticle dispersions upon the addition of adsorbing polymer. We find weak segmental adsorption energies of ~0.2 k B T for PEO in water and buffer, consistent with the observed phase separation. For PVP in water, segmental adsorption energies of order ~1.6 k B T support bridging flocculation in water, whereas a weaker adsorption energy of ~0.7 k B T in buffer is consistent with a lack of significant bridging flocculation. The difference between bridging and depletion is distinguished by visual appearance, rheological measurements, and small-angle neutron scattering (SANS). SANS measurements of PVP phase separated samples show a loss of the fractal region at low wavevector with increasing polymer concentration in moving from bridge flocculated to the depletion phase separation regime. There was also a concurrent shift in the interaction peak to lower Q values. These two effects signify a decrease in the density of the fractal aggregates with changing phase separation mechanism, consistent with a shift from bridging flocculation to depletion attraction. The ratio of polymer concentration to polymer entanglement concentration (c/c*) required to induce phase separation increases with increasing R g /R in agreement with theoretical predictions of the polymer reference interaction site model (PRISM). This trend opposes classical depletion theories because the classical theories do not account for polymer entanglement, amongst others, by assuming non-interacting polymers that interact as hard spheres. This assumption is clearly violated when R g> R when the nanoparticles can interpenetrate the polymer coils. Cationic nanovesicles are formed by sonication and characterized by viscometry, dynamic light scattering, and small-angle neutron scattering. The phase behavior of PVP - nanovesicle mixtures are measured and compared to the cationic nanoparticle system. Unlike the colloids, the nanovesicles do not phase separate on a short time scale, but rather, become unstable and revert back to the birefringent lamellae structure due to electrostatic repulsion of the charged heard groups. The rate of this coalescence is enhanced by the addition of polymer. This work provides a complete data set exploring bridging flocculation and depletion induced phase separation in the protein limit. As such it can be used to test theoretical work and to provide guidance in formulating polymer - nanoparticle mixtures. Extension to systems of nanovesicles highlights the differences inherent in selfassembled systems as compared to nanoparticles. The results can help guide industrial formulations containing mixtures of polymer, nanoparticles, and surfactant mesophases.

Download or read book A Real space Study of Phase Behaviour and Slow Dynamics in Colloid polymer Mixtures written by Isla Zhang and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design of Self Assembling Materials written by Ivan Coluzza and published by Springer. This book was released on 2018-03-23 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides in-depth insights into assembling dynamics of proteins, DNA and other nanoparticles. The applications of basic knowledge in the development of artificial self-assembling systems will be discussed and state of the art methodology in the field will be presented.This interdisciplinary work brings together aspects of different fields of expertise such as Biology, Physics and Material Sciences and is intended for researchers, professors and graduate students interested in the design of self-assembling materials.

Download or read book New Models of the Cell Nucleus Crowding Entropic Forces Phase Separation and Fractals written by Ronald Hancock and published by Academic Press. This book was released on 2013-12-27 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: International Review of Cell and Molecular Biology presents current advances and comprehensive reviews in cell biology--both plant and animal. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth. Impact factor for 2012: 4.973. Ideas from the fields of biophysics, physical chemistry, of polymer and colloid, and soft matter science have helped clarify the structure and functions of the cell nucleus. The development of powerful methods for modeling conformations and interactions of macromolecules has also contributed. The book aims to encourage cell and molecular biologists to become more familiar with and understand these new concepts and methods, and the crucial contributions they are making to our perception of the nucleus. This is the first volume to present a comprehensive review of New Models of the Cell Nucleus

Download or read book Phase Separation in Colloid polymer Mixtures written by Juan Zhou and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phase Behavior Fluid Structure Slow Dynamics in Polymer colloid Mixtures written by Yeng-Long Chen and published by . This book was released on 2003 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soft Matter And Biomaterials On The Nanoscale The Wspc Reference On Functional Nanomaterials Part I In 4 Volumes written by and published by World Scientific. This book was released on 2020-06-24 with total page 1885 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is indexed in Chemical Abstracts ServiceSoft and bio-nanomaterials offer a tremendously rich behavior due to the diversity and tailorability of their structures. Built from polymers, nanoparticles, small and large molecules, peptoids and other nanoscale building blocks, such materials exhibit exciting functions, either intrinsically or through the engineering of their organization and combination of blocks. Thus, it is not surprising that a variety of challenges, for example, in energy storage, environment protection, advanced manufacturing, purification and healthcare, can be addressed using these materials. The recent advances in understanding the behavior of soft matter and biomaterials are being actively translated into functional materials systems and devices, which take advantages of newly discovered and specifically created morphologies with desired properties. This major reference work presents a detailed overview of recent research developments on fundamental and application-inspired aspects of soft and bio-nanomaterials and their emerging functions, and will be divided into four volumes: Vol 1: Soft Matter under Geometrical Confinement: From Fundamentals at Planar Surfaces and Interfaces to Functionalities of Nanoporous Materials; Vol 2: Polymers on the Nanoscale: Nano-structured Polymers and Their Applications; Vol 3: Bio-Inspired Nanomaterials: Nanomaterials Built from Biomolecules and Using Bio-derived Principles; Vol 4: Nanomedicine: Nanoscale Materials in Nano/Bio Medicine.

Download or read book Phase Behavior of Polymer Blends written by Karl Freed and published by Springer Science & Business Media. This book was released on 2005-09-01 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of a Shear Flow on Colloidal Depletion Interaction written by Christoph July and published by Forschungszentrum Jülich. This book was released on 2012 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soft Condensed Matter Physics in Molecular and Cell Biology written by W.C.K. Poon and published by CRC Press. This book was released on 2006-01-13 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soft condensed matter physics, which emerged as a distinct branch of physics in the 1990s, studies complex fluids: liquids in which structures with length scale between the molecular and the macroscopic exist. Polymers, liquid crystals, surfactant solutions, and colloids fall into this category. Physicists deal with properties of soft matter system

Download or read book Time Resolved Single Molecule Fluorescence Spectroscopy on Surface Tethered and Freely Diffusing Proteins written by Diaa Atta and published by Forschungszentrum Jülich. This book was released on 2012 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: