Phase Transitions in Polymers by Stephen Z.D. Cheng

By Stephen Z.D. Cheng

A classical metastable nation possesses a neighborhood loose strength minimal at limitless sizes, yet no longer a world one. this idea is part dimension self reliant. we've studied a few experimental effects and proposed a brand new idea that there exists quite a lot of metastable states in polymers on varied size scales the place their metastability is seriously made up our minds via the part dimension and dimensionality. Metastable states also are saw in part changes which are kinetically impeded at the pathway to thermodynamic equilibrium. This was once illustrated in structural and morphological investigations of crystallization and mesophase transitions, liquid-liquid section separation, vitrification and gel formation, in addition to combos of those transformation techniques. The section behaviours in polymers are therefore ruled by way of interlinks of metastable states on diversified size scales. this idea effectively explains many experimental observations and gives a brand new strategy to attach varied features of polymer physics.

Show description

Read or Download Phase Transitions in Polymers PDF

Similar polymers & textiles books

Adsorptions by Carbons

This ebook covers the main major features of adsorption by means of carbons, trying to fill the present hole among the fields of adsorption and carbonaceous fabrics. either simple and utilized points are awarded. the 1st part of the ebook introduces actual adsorption and carbonaceous fabrics, and is through a piece in regards to the basics of adsorption through carbons.

Handbook of Textile Fibres (Woodhead Publishing Series in Textiles)

A entire survey of the average fibres – animal, vegetable and mineral – on which we depended for our textiles till relatively lately.

Nanofibers and Nanotechnology in Textiles

Nanotechnology is revolutionising the realm of fabrics. this crucial publication stories its influence in constructing a brand new iteration of cloth fibers with improved performance and quite a lot of purposes. the 1st a part of the booklet studies nanofiber creation, discussing how diverse fiber varieties might be produced utilizing electrospinning thoughts.

Polymer Physics: From Suspensions to Nanocomposites and Beyond

Supplying a accomplished evaluation of the cutting-edge complicated learn within the box, Polymer Physics explores the interrelationships between polymer constitution, morphology, and actual and mechanical habit. that includes contributions from well known specialists, the publication covers the fundamentals of significant components in polymer physics whereas projecting into the long run, making it a invaluable source for college kids and chemists, chemical engineers, fabrics scientists, and polymer scientists in addition to pros in comparable industries.

Extra resources for Phase Transitions in Polymers

Sample text

Turnbull and Fisher derived an equation for the rate of homogeneous nucleation (i) during the beginning of crystal formation. This equation is dominated by two opposing factors: the nucleation barrier free energy (DG) and the activation free energy for diffusion (DGZ) (Turnbull and Fisher, 1949):  i¼    NkT ÀðDG þ DGZ Þ exp h ðkTx Þ ð2:9Þ 32 Stephen Z. D. Cheng where h is the Planck constant, N is the number of uncrystallized particles that can participate in the nucleation process, and Tx is the temperature at which crystallization takes place.

The changes in entropy can also be determined using the entropic contributions of positional, orientational, and conformational order, as described by the crystal melting Eq. 2 (Wunderlich, 1980; Wunderlich and Grebowicz, 1984). The correlations between the change in entropy and specific liquid crystalline transitions, such as the nematic–smectic transition, are also less quantitative than the correlations found for crystal melting. A significant difficulty in carrying out a quantitative analysis of liquid crystalline transitions is that liquid crystals consist of both a rigid mesogen and flexible tails.

This region is unstable, and the mixture spontaneously decomposes into two equilibrium concentration phases at a specific temperature (Cahn and Hilliard, 1958). , the phase morphology pathway taken to develop the ultimate equilibrium morphology. 4. Kinetics of liquid–liquid phase separation in binary mixtures Considerable attention has been given to both the theoretical and experimental aspects of liquid–liquid phase separation kinetics in binary mixtures. The phase separation processes can generally be broken down into three stages: the early, intermediate, and late stages.

Download PDF sample

Rated 4.75 of 5 – based on 19 votes