Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 242
Book Description
On the Evolution of Phase Separation in Polymer Blends
Author: Fundamentals of Phase Separation in Polymer Blend Thin Films
Author: Sam CoveneyPublisher: Springer
ISBN: 3319193996
Category : Science
Languages : en
Pages : 179
Book Description
This work sheds new light on fundamental aspects of phase separation in polymer-blend thin films. A key feature underlying the theoretical models is the unification of one-dimensional thermodynamic phase equilibria with film evolution phenomena in two- and three dimensions. Initially, an established 'phase portrait' method, useful for visualising and calculating phase equilibria of polymer-blend films, is generalised to systems without convenient simplifying symmetries. Thermodynamic equilibria alone are then used to explain a film roughening mechanism in which laterally coexisting phases can have different depths in order to minimise free energy. The phase portraits are then utilised to demonstrate that simulations of lateral phase separation via a transient wetting layer, which conform very well with experiments, can be satisfactorily explained by 1D phase equilibria and a 'surface bifurcation' mechanism. Lastly, a novel 3D model of coupled phase separation and dewetting is developed, which demonstrates that surface roughening shadows phase separation in thin films.
Double-stage Phase Separation in Dynamically Asymmetric Ternary Polymer Blends
Author: Chen KuangPublisher:
ISBN:
Category : Polymers
Languages : en
Pages : 154
Book Description
Phase separation in complex fluids such as polymers has been the subject of several experimental and theoretical studies in recent years. Understanding the phase separation mechanisms and controlling morphological evolution are very important for designing various advanced materials with novel mechanical, optical, electrical, and transport properties. In polymer blends, dynamic asymmetry is induced by a large difference in glass transition temperature. In this work, phase separation behavior of ternary blends of polystyrene/poly(vinyl methyl ether)/polyisoprene, PS/PVME/PI, and polystyrene/poly(vinyl methyl ether)/poly(ethyl methacrylate), PS/PVME/PEMA are investigated. Ternary blends of PS/PVME/PI and PS/PVME/PEMA exhibit complex phase separation behavior since PS and PVME have a lower critical solution temperature (LCST) behavior, while PI and PS (or PVME), PEMA and PS (or PVME) have upper critical solution temperature (UCST) behavior. 2D and 3D phase diagrams for these two ternary systems were plotted by both Flory-Huggins incompressible and regular solution compressible models. Casting the solutions of PS/PVME/PI and PS/PVME/PEMA blends form two phase-separated domains in most compositions: (i) PI-rich or PEMA rich, and (ii) PS/PVME-rich. Post-annealing of such samples leads to the second-stage phase separation due to unfavorable interaction of PS and PVME at temperatures about 100°C. Such behavior that is observed for the first time provides a new potential method for making different morphologies with the same system by changing annealing parameters and composition. Washing one polymer at a time using a selective solvent is used to study the morphology of ternary blends. Optical microscopy and scanning electron microscopy are used to study the kinetics and morphology of viscoelastic phase separation (VPS) in ternary blends.
Initial Stages of Phase Separation in Polymer Blends Near the Limit of Metastability
Author: Amy Adams LefebvrePhase Separation in Polymer Blends
Author: Dahn KatzenEvolution of Phase Behavior and Dynamics in Reactive Polymer Blends
Author: Daniel J. DuffyPublisher:
ISBN:
Category : Phase partition
Languages : en
Pages : 684
Book Description
Effect of Temperature and Shear on Phase Separation in Liquid Crystalline Polymer/polycarbonate Blends
Author: Kam-Wa (Danny) LeeJoint Meeting on Multicomponent Polymers and Polyelectrolytes
Author: Eric J. AmisPublisher: DIANE Publishing
ISBN: 0788171836
Category :
Languages : en
Pages : 55
Book Description
Proceedings of a conference organized by Polymer Blends & Processing Group, National Institute of Standards & Technology (NIST), Hashimoto Polymer Phasing Project, Exploratory Research for Advanced Technology (ERATO), & Japan Science & Technology Corporation (JST). Includes plenary lectures on phase transitions & ordering processes & polymer blends processing; & lectures in the areas of structure & morphology, phase separation, polyelectrolytes, & surfaces & interfaces.
Wetting and Phase Separation in Thin Film Polymer Blends
Author: Hao WangPhase Behavior of Polymer Blends
Author: Karl FreedPublisher: Springer Science & Business Media
ISBN: 9783540256809
Category : Technology & Engineering
Languages : en
Pages : 224
Book Description