Download or read book Physical Aging of Thin and Ultrathin Glassy Polymer Films written by Brandon William Rowe and published by . This book was released on 2010 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research effort investigated the influence of confinement on the physical aging behavior of thin and ultrathin glassy polymer membranes. Membrane permeability changes with time due to physical aging, and for reasons not completely understood, the rate of permeability change can become orders of magnitude faster in films thinner than one micron. Special experimental techniques were developed to enable the study of free standing, ultrathin glassy polymer films using gas permeability measurements. The gas transport properties and physical aging behavior of free-standing glassy polysulfone (PSF) and Matrimid® films from 18-550 nm thick are presented. Physical aging persists in glassy films approaching the length scale of individual polymer coils. The membranes exhibited significant reductions in gas permeability and increases in selectivity with aging time. Additionally, the influence of physical aging on the free volume profile in thin PSF films was investigated using variable energy positron annihilation lifetimespectroscopy (PALS). The films exhibited decreasing o-Ps lifetime during physical aging, while o-Ps intensity remained constant. The o-Ps lifetime was reduced at lower implantation energies, indicating smaller free volume elements near the film surface. Thin films aged dramatically faster than bulk PSF and the PALS results agree favorably to behavior tracked by gas permeability measurements. The physical aging behavior of ultrathin films with different previous histories was also studied. The state of these materials was modulated by various conditioning treatments. Regardless of the previous history, the nature of the aging response was consistent with the aging behavior of an untreated film that was freshly quenched from above Tg, i.e., permeability decreased and pure gas selectivity increased with aging time. However, the extent of aging-induced changes in transport properties of these materials depended strongly on previous history. The properties of these ultrathin films deviate dramatically from bulk behavior, and the nature of these deviations is consistent with enhanced mobility and reduced Tg in ultrathin films, which allows them to reach a lower free volume state more quickly than bulk material. The Struik physical aging model was extended to account for the influence of film thickness on aging, and was shown to accurately describe the experimental data.

Download or read book Physical Aging of Thin Glassy Polymer Films written by Yu Huang and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physical Aging of Glassy Polymers in Confined Environments written by Thomas Matthew Murphy and published by . This book was released on 2012 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research project investigated the physical aging of glassy polymers in confined environments. Many recent studies of aging in glassy polymers have observed that aging behavior is often strongly affected by confinement. Understanding aging in confined environments (e.g., thin polymer films and nanocomposites) is vital for predicting long-term performance in applications that use confined glassy polymers, such as gas separation membranes and advanced nanocomposite materials. Aging in bulk and layered films produced via layer-multiplying co-extrusion was studied using gas permeability measurement and differential scanning calorimetry (DSC). The layered films consisted of polysulfone (PSF) and a rubbery co-layering material, with PSF layers ranging in thickness from ~185 nm to ~400 nm. Gas permeation aging studies at 35 °C revealed that the PSF layers in layered films aged in a manner that was similar to bulk PSF and independent of layer thickness. This finding differs from what was observed previously in freestanding PSF films, in which aging depended strongly on thickness and was accelerated relative to bulk. Isothermal aging studies at 170 °C and cooling rate studies were performed on both bulk and layered samples using DSC. The aging of the PSF layers was similar to aging in bulk PSF for films having PSF layer thicknesses of ~640 nm and ~260 nm, while the film with 185 nm PSF layers showed a slightly higher aging rate than that of bulk PSF. The results of the DSC studies generally support the conclusions of our gas permeation aging studies. The absence of strong thickness dependence in aging studies of layered films tends to support the idea that the effect of film thickness on physical aging stems from interfacial characteristics and not merely thickness per se. The physical aging of thin polystyrene (PS) films at 35 °C was also investigated using gas permeation techniques. PS films of 400 nm and 800 nm did not exhibit aging behavior that was highly accelerated relative to bulk or strongly dependent on film thickness. At the thicknesses and aging temperature considered, the aging of PS shows much weaker thickness dependence than that seen in polymers like PSF and Matrimid.

Download or read book Carbon Dioxide Plasticization and Conditioning of Thin Glassy Polymer Films Monitored by Gas Permeability and Optical Methods written by Norman Randall Horn and published by . This book was released on 2012 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research project investigated physical aging and carbon dioxide plasticization behavior of glassy polymer films. Recent studies have shown that thin glassy polymer films undergo physical aging more rapidly than thick films. This suggests that thickness may also play a role in the plasticization and conditioning responses of thin glassy films in the presence of highly-sorbing penetrants such as CO2. The effect of film thickness on CO2 permeation and sorption was studied extensively through carefully defined and controlled methods that provide a basis for future study of plasticization behavior. Thin films are found to be more sensitive than thick films to CO2 exposure, undergoing more extensive and rapid plasticization at any pressure. The response of glassy polymers films to CO2 is not only dependent on thickness, but also on aging time, CO2 pressure, exposure time, and prior history. Thin films experiencing constant CO2 exposure for longer periods of time exhibit an initial large increase in CO2 permeability, which eventually reaches a maximum, followed by a significant decrease in permeability for the duration of the experiment. Thick films, in contrast, do not seem to exhibit this trend for the range of conditions explored. For a series of different polymers, the extent of plasticization response tracks with CO2 solubility. There is little data available for gas sorption in thin glassy polymer films. In this work, a novel method involving spectroscopic ellipsometry is used to obtain simultaneously the film thickness and CO2 sorption capacity for thin glassy polymer films. This allows a more comprehensive look at CO2 permeability, sorption, and diffusivity as a function of both CO2 pressure and exposure time. Like the gas permeation data, these experiments suggest that thin film sorption behavior is substantially different than that of thick film counterparts. Dynamic ellipsometry experiments show that refractive index minima, fractional free volume maxima, and CO2 diffusivity maxima correlate well with observed CO2 permeability maxima observed for thin Matrimid® films. These experiments demonstrate that plasticization and physical aging are competing processes. Aging, however, dominates over long time scales. Over time, CO2 diffusivity is most affected by these competing effects, and the evolution of CO2 diffusivity is shown to be the main contributing factor to changes in CO2 permeability at constant pressure.

Download or read book Non equilibrium Phenomena in Confined Soft Matter written by Simone Napolitano and published by Springer. This book was released on 2015-08-28 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with those properties of non-equilibrium soft matter that deviate greatly from the bulk properties as a result of nanoscale confinement.The ultimate physical origin of these confinement effects is not yet fully understood. At the state of the art, the discussion on confinement effects focuses on equilibrium properties, finite size effects and interfacial interactions. However this is a limited vision which does not fully capture the peculiar behaviour of soft matter under confinement and some exotic phenomena that are displayed. This volume will be organized in the following three main themes. Equilibration and physical aging: treating non-equilibrium via the formal methodology of statistical physics in bulk, we analyse physical origin of the non-equilibrium character of thin polymer. We then focus on the impact of nanoconfinement on the equilibration of glasses of soft matter (a process of tremendous technological interest, commonly known as physical aging), comparing the latest trends of polymers in experiments, simulations with those of low-molecular weight glass formers. Irreversible adsorption: the formation of stable adsorbed layers occurs at timescales much larger than the time necessary to equilibrate soft matter in bulk. Recent experimental evidence show a strong correlation between the behaviour of polymers under confinement and the presence of a layer irreversibly adsorbed onto the substrate. This correlation hints at the possibility to tailor the properties of ultrathin films by controlling the adsorption kinetics. The book reports physical aspects of irreversible chain adsorption, such as the dynamics, structure, morphology, and crystallization of adsorbed layers. Glass transition and material properties: this section of the book focuses on the spread of absolute values in materials properties of confined systems, when measured by different experimental and computation techniques and a new method to quantify the effects of confinement in thin films and nanocomposites independently on the investigation procedure will be presented.

Download or read book Glass Transition Dynamics and Heterogeneity of Polymer Thin Films written by Toshiji Kanaya and published by Springer. This book was released on 2012-12-15 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mobility Gradient of Polystyrene in Films Supported on Solid Substrates, by Yoshihisa Fujii, Hiroshi Morita, Atsushi Takahara and Keiji Tanaka Probing Properties of Polymers in Thin Films Via Dewetting, by Günter Reiter Heterogeneous and Aging Dynamics in Single and Stacked Thin Polymer Films, by Koji Fukao, Takehide Terasawa, Kenji Nakamura, Daisuke Tahara Heterogeneous Dynamics of Polymer Thin Films as Studied by Neutron Scattering, by Rintaro Inoue and Toshiji Kanaya

Download or read book Thin Glassy Polymer Films written by P. H. Pfromm and published by . This book was released on 1996 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polymer Glasses written by Connie B. Roth and published by CRC Press. This book was released on 2016-12-12 with total page 587 pages. Available in PDF, EPUB and Kindle. Book excerpt: "the present book will be of great value for both newcomers to the field and mature active researchers by serving as a coherent and timely introduction to some of the modern approaches, ideas, results, emerging understanding, and many open questions in this fascinating field of polymer glasses, supercooled liquids, and thin films" –Kenneth S. Schweizer, Morris Professor of Materials Science & Engineering, University of Illinois at Urbana-Champaign (from the Foreword) This book provides a timely and comprehensive overview of molecular level insights into polymer glasses in confined geometries and under deformation. Polymer glasses have become ubiquitous to our daily life, from the polycarbonate eyeglass lenses on the end of our nose to large acrylic glass panes holding water in aquarium tanks, with advantages over glass in that they are lightweight and easy to manufacture, while remaining transparent and rigid. The contents include an introduction to the field, as well as state of the art investigations. Chapters delve into studies of commonalities across different types of glass formers (polymers, small molecules, colloids, and granular materials), which have enabled microscopic and molecular level frameworks to be developed. The authors show how glass formers are modeled across different systems, thereby leading to treatments for polymer glasses with first-principle based approaches and molecular level detail. Readers across disciplines will benefit from this topical overview summarizing the key areas of polymer glasses, alongside an introduction to the main principles and approaches.

Download or read book Gas Transport in Glassy Polymers written by Maria Grazia De Angelis and published by MDPI. This book was released on 2021-04-22 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue of Membranes focuses on several new aspects of fluid transport in glassy polymers, with application in relevant membrane separations such as gas purification, VOC removal and CO2 capture. In particular, the focus lies on novel experimental techniques, and detailed characterization of specific phenomena like polar and multicomponent interactions during transport. The properties of novel materials, such as mixed matrix membranes based on glassy polymers and different selective fillers, are also presented. A critical review of existing modeling approaches to describe the sorption and transport in glassy polymers suitable for membrane separations is provided, including both macroscopic and atomistic models, and relying both on the standard solution–diffusion process and on the facilitated transport mechanism.

Download or read book Surface and Confinement Effects on the Glass Transition Temperature for Ultrathin Polymer Films written by David Scott Fryer and published by . This book was released on 2000 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polymer Physics written by Leszek A. Utracki and published by John Wiley & Sons. This book was released on 2011-02-14 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a comprehensive review of the state-of-the-art advanced research in the field, Polymer Physics explores the interrelationships among polymer structure, morphology, and physical and mechanical behavior. Featuring contributions from renowned experts, the book covers the basics of important areas in polymer physics while projecting into the future, making it a valuable resource for students and chemists, chemical engineers, materials scientists, and polymer scientists as well as professionals in related industries.

Download or read book Handbook of Thermal Analysis and Calorimetry written by and published by Elsevier. This book was released on 2018-03-12 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Thermal Analysis and Calorimetry: Recent Advances, Techniques and Applications, Volume Six, Second Edition, presents the latest in a series that has been well received by the thermal analysis and calorimetry community. This volume covers recent advances in techniques and applications that complement the earlier volumes. There has been tremendous progress in the field in recent years, and this book puts together the most high-impact topics selected for their popularity by new editors Sergey Vyazovkin, Nobuyoshi Koga and Christoph Schick—all editors of Thermochimica Acta. Among the important new techniques covered are biomass conversion; sustainable polymers; polymer nanocompsoties; nonmetallic glasses; phase change materials; propellants and explosives; applications to pharmaceuticals; processes in ceramics, metals, and alloys; ionic liquids; fast-scanning calorimetry, and more. Features 19 all-new chapters to bring readers up to date on the current status of the field Provides a broad overview of recent progress in the most popular techniques and applications Includes chapters authored by a recognized leader in each field and compiled by a new team of editors, each with at least 20 years of experience in the field of thermal analysis and calorimetry Enables applications across a wide range of modern materials, including polymers, metals, alloys, ceramics, energetics and pharmaceutics Overviews the current status of the field and summarizes recent progress in the most popular techniques and applications

Download or read book Long Term Durability of Polymeric Matrix Composites written by Kishore V. Pochiraju and published by Springer Science & Business Media. This book was released on 2011-09-25 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-Term Durability of Polymeric Matrix Composites presents a comprehensive knowledge-set of matrix, fiber and interphase behavior under long-term aging conditions, theoretical modeling and experimental methods. This book covers long-term constituent behavior, predictive methodologies, experimental validation and design practice. Readers will also find a discussion of various applications, including aging air craft structures, aging civil infrastructure, in addition to engines and high temperature applications.

Download or read book 27th European Symposium on Computer Aided Process Engineering written by and published by Elsevier. This book was released on 2017-09-21 with total page 3064 pages. Available in PDF, EPUB and Kindle. Book excerpt: 27th European Symposium on Computer Aided Process Engineering, Volume 40 contains the papers presented at the 27th European Society of Computer-Aided Process Engineering (ESCAPE) event held in Barcelona, October 1-5, 2017. It is a valuable resource for chemical engineers, chemical process engineers, researchers in industry and academia, students, and consultants for chemical industries. Presents findings and discussions from the 27th European Society of Computer-Aided Process Engineering (ESCAPE) event

Download or read book Polymer Thin Films written by Ophelia Kwan Chui Tsui and published by World Scientific. This book was released on 2008 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ch. 1. Block copolymer thin films / J.-Y. Wang, S. Park and T. P. Russell -- ch. 2. Equilibration of block copolymer films on chemically patterned surfaces / G. S. W. Craig, H. Kang and P. F. Nealey -- ch. 3. Structure formation and evolution in confined cylinder-forming block copolymers / G. J. A. Sevink and J. G. E. M. Fraaije -- ch. 4. Block copolymer lithography for magnetic device fabrication / J. Y. Cheng and C. A. Ross -- ch. 5. Hierarchical structuring of polymer nanoparticles by self-organization / M. Shimomura ... [et al.] -- ch. 6. Wrinkling polymers for surface structure control and functionality / E. P. Chan and A. J. Crosby -- ch. 7. Crystallization in polymer thin films: morphology and growth / R. M. Van Horn and S. Z. D. Cheng -- ch. 8. Friction at soft polymer surface / M. K. Chaudhury, K. Vorvolakos and D. Malotky -- ch. 9. Relationship between molecular architecture, large-strain mechanical response and adhesive performance of model, block copolymer-based pressure sensitive adhesives / C. Creton and K. R. Shull -- ch. 10. Stability and dewetting of thin liquid films / K. Jacobs, R. Seemann and S. Herminghaus -- ch. 11. Anomalous dynamics of polymer Films / O. K. C. Tsui.

Download or read book Dynamics in Geometrical Confinement written by Friedrich Kremer and published by Springer. This book was released on 2014-06-03 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the dynamics of low molecular weight and polymeric molecules when they are constrained under conditions of geometrical confinement. It covers geometrical confinement in different dimensionalities: (i) in nanometer thin layers or self supporting films (1-dimensional confinement) (ii) in pores or tubes with nanometric diameters (2-dimensional confinement) (iii) as micelles embedded in matrices (3-dimensional) or as nanodroplets. The dynamics under such conditions have been a much discussed and central topic in the focus of intense worldwide research activities within the last two decades. The present book discusses how the resulting molecular mobility is influenced by the subtle counterbalance between surface effects (typically slowing down molecular dynamics through attractive guest/host interactions) and confinement effects (typically increasing the mobility). It also explains how these influences can be modified and tuned, e.g. through appropriate surface coatings, film thicknesses or pore diameters. "Dynamics in Confinement" sums up the present state-of-the-art and introduces to the analytical methods of choice for the study of dynamics in nanometer-scale confinement.

Download or read book Structuration and Glass Transition Temperature of the Adsorbed Polymer Layer written by Aparna Beena Unni and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Size reduction is one of the very important factors considered during the device fabrication. Polymer thin films, which is a crucial component of many devices, shows numerous anomalous behaviors when they are confined by their thickness. This work is dedicated to understand the confinement effects and properties of ultrathin polymer films. At the very outset we observed the density evolution of polymer films with the film thickness by means of adsorbing ceria nanoparticles onto the polymer surfaces. The second study threw light on the stability/instability domains of such films, which led to a method for fabricating stable films which are less than 7nm, by means of rinsing with a good solvent. In the following study, it was found that there is a significant influence of solvent used rinsing on the characteristics of the polymer residual layer. Finally the glass transition behavior of the polymer residual layer was analyzed, which showed multiple glass transition temperatures, that points to the existence of two physical states in the polymer residual layer. Altogether, this work contributes towards a better understanding of the density, stability and glass transition properties of polymer films confined by their thickness.