Phase Transitions in Polymers: The Role of Metastable States

Phase Transitions in Polymers: The Role of Metastable States
Author: Stephen Z.D. Cheng
Publisher: Elsevier
Total Pages: 325
Release: 2008-09-10
Genre: Science
ISBN: 0080558208

A classical metastable state possesses a local free energy minimum at infinite sizes, but not a global one. This concept is phase size independent. We have studied a number of experimental results and proposed a new concept that there exists a wide range of metastable states in polymers on different length scales where their metastability is critically determined by the phase size and dimensionality. Metastable states are also observed in phase transformations that are kinetically impeded on the pathway to thermodynamic equilibrium. This was illustrated in structural and morphological investigations of crystallization and mesophase transitions, liquid-liquid phase separation, vitrification and gel formation, as well as combinations of these transformation processes. The phase behaviours in polymers are thus dominated by interlinks of metastable states on different length scales. This concept successfully explains many experimental observations and provides a new way to connect different aspects of polymer physics.* Written by a leading scholar and industry expert* Presents new and cutting edge material encouraging innovation and future research* Connects hot topics and leading research in one concise volume

Current Topics in Elastomers Research

Current Topics in Elastomers Research
Author: Anil K. Bhowmick
Publisher: CRC Press
Total Pages: 1105
Release: 2008-05-07
Genre: Technology & Engineering
ISBN: 1420007181

From weather-proof tires and artificial hearts to the o-rings and valve seals that enable successful space exploration, rubber is an indispensable component of modern civilization. Stiff competition and stringent application requirements foster continuous challenges requiring manufacturers to fund ever-expanding research projects. However, this vas

Directed Self-assembly of Block Co-polymers for Nano-manufacturing

Directed Self-assembly of Block Co-polymers for Nano-manufacturing
Author: Roel Gronheid
Publisher: Woodhead Publishing
Total Pages: 328
Release: 2015-07-17
Genre: Technology & Engineering
ISBN: 0081002610

The directed self-assembly (DSA) method of patterning for microelectronics uses polymer phase-separation to generate features of less than 20nm, with the positions of self-assembling materials externally guided into the desired pattern. Directed self-assembly of Block Co-polymers for Nano-manufacturing reviews the design, production, applications and future developments needed to facilitate the widescale adoption of this promising technology. Beginning with a solid overview of the physics and chemistry of block copolymer (BCP) materials, Part 1 covers the synthesis of new materials and new processing methods for DSA. Part 2 then goes on to outline the key modelling and characterization principles of DSA, reviewing templates and patterning using topographical and chemically modified surfaces, line edge roughness and dimensional control, x-ray scattering for characterization, and nanoscale driven assembly. Finally, Part 3 discusses application areas and related issues for DSA in nano-manufacturing, including for basic logic circuit design, the inverse DSA problem, design decomposition and the modelling and analysis of large scale, template self-assembly manufacturing techniques. - Authoritative outlining of theoretical principles and modeling techniques to give a thorough introdution to the topic - Discusses a broad range of practical applications for directed self-assembly in nano-manufacturing - Highlights the importance of this technology to both the present and future of nano-manufacturing by exploring its potential use in a range of fields

Singularities in PDE and the Calculus of Variations

Singularities in PDE and the Calculus of Variations
Author: Stanley Alama
Publisher: American Mathematical Soc.
Total Pages: 284
Release:
Genre: Mathematics
ISBN: 9780821873311

This book contains papers presented at the "Workshop on Singularities in PDE and the Calculus of Variations" at the CRM in July 2006. The main theme of the meeting was the formation of geometrical singularities in PDE problems with a variational formulation. These equations typically arise in some applications (to physics, engineering, or biology, for example) and their resolution often requires a combination of methods coming from areas such as functional and harmonic analysis, differential geometry and geometric measure theory. Among the PDE problems discussed were: the Cahn-Hilliard model of phase transitions and domain walls; vortices in Ginzburg-Landau type models for superconductivity and superfluidity; the Ohna-Kawasaki model for di-block copolymers; models of image enhancement; and Monge-Ampere functions. The articles give a sampling of problems and methods in this diverse area of mathematics, which touches a large part of modern mathematics and its applications.

Holographic Sensors

Holographic Sensors
Author: Ali Kemal Yetisen
Publisher: Springer
Total Pages: 175
Release: 2014-12-03
Genre: Science
ISBN: 3319135848

This thesis presents a theoretical and experimental approach for the rapid fabrication, optimization and testing of holographic sensors for the quantification of pH, organic solvents, metal cations, and glucose in solutions. Developing non-invasive and reusable diagnostics sensors that can be easily manufactured will support the monitoring of high-risk individuals in any clinical or point-of-care setting. Sensor fabrication approaches outlined include silver-halide chemistry, laser ablation and photopolymerization. The sensors employ off-axis Bragg diffraction gratings of ordered silver nanoparticles and localized refractive index changes in poly (2-hydroxyethyl methacrylate) and polyacrylamide films. The sensors exhibited reversible Bragg peak shifts, and diffracted the spectrum of narrow-band light over the wavelength range λpeak ≈ 495-1100 nm. Clinical trials of glucose sensors in the urine samples of diabetic patients demonstrated that they offer superior performance compared to commercial high-throughput urinalysis devices. Lastly, a generic smartphone application to quantify colorimetric tests was developed and tested for both Android and iOS operating systems. The sensing platform and smartphone application may have implications for the development of low-cost, reusable and equipment-free point-of-care diagnostic devices.

Nanostructured Polymer Blends

Nanostructured Polymer Blends
Author: Sabu Thomas
Publisher: William Andrew
Total Pages: 570
Release: 2013-11-28
Genre: Technology & Engineering
ISBN: 1455731609

Over 30% of commercial polymers are blends or alloys or one kind or another. Nanostructured blends offer the scientist or plastics engineer a new range of possibilities with characteristics including thermodynamic stablility; the potential to improve material transparency, creep and solvent resistance; the potential to simultaneously increase tensile strength and ductility; superior rheological properties; and relatively low cost. Nanostructured Polymer Blends opens up immense structural possibilities via chemical and mechanical modifications that generate novel properties and functions and high-performance characteristics at a low cost. The emerging applications of these new materials cover a wide range of industry sectors, encompassing the coatings and adhesives industry, electronics, energy (photovoltaics), aerospace and medical devices (where polymer blends provide innovations in biocompatible materials). This book explains the science of nanostructure formation and the nature of interphase formations, demystifies the design of nanostructured blends to achieve specific properties, and introduces the applications for this important new class of nanomaterial. All the key topics related to recent advances in blends are covered: IPNs, phase morphologies, composites and nanocomposites, nanostructure formation, the chemistry and structure of additives, etc. - Introduces the science and technology of nanostructured polymer blends – and the procedures involved in melt blending and chemical blending to produce new materials with specific performance characteristics - Unlocks the potential of nanostructured polymer blends for applications across sectors, including electronics, energy/photovoltaics, aerospace/automotive, and medical devices (biocompatible polymers) - Explains the performance benefits in areas including rheological properties, thermodynamic stablility, material transparency, solvent resistance, etc.

Block Copolymers

Block Copolymers
Author: Francisco Balta Calleja
Publisher: CRC Press
Total Pages: 604
Release: 2000-06-09
Genre: Technology & Engineering
ISBN: 9780824703820

A summary of block copolymer chemical structures and synthesis. It discusses physical methods of characterization such as computer simulation, microhardness, dielectric spectroscopy, thermal mechanical relaxation, ultrasonic characterization, transmission electron microscopy, X-ray scattering, and NMR, among others. It also outlines rheological and processing parameters in the multiphase polymer systems with stable microstructures.

The Pursuit of Perfect Packing

The Pursuit of Perfect Packing
Author: Denis Weaire
Publisher: CRC Press
Total Pages: 147
Release: 2000-01-01
Genre: Mathematics
ISBN: 142003331X

In 1998 Thomas Hales dramatically announced the solution of a problem that has long teased eminent mathematicians: what is the densest possible arrangement of identical spheres? The Pursuit of Perfect Packing recounts the story of this problem and many others that have to do with packing things together. The examples are taken from mathematics, phy