Volume Viscoelasticity of Amorphous Polymers

Influence of Viscoelasticity of Amorphous Layers on Longitudinal Accordion Mode Seattering of Polymers

The normal viscoelasticity of the amorphous component yields a rapid exponential decrease of the amplitude of the longitudinal accordion type oscillations in the defect areas of the macromolecule in the crystalline core and in the amorphous layers on the folds containing surfaces of the lamellae. The macrornolecule in the amorphous layer and in crystal defects changes direction and, hence, cann...

Molecularly-based numerical evaluation of free volume in amorphous polymers

A study of the microstructure of polymers is essential for the understanding of their anomalous diffusion properties. The concept of free volume may be utilized to study relaxation phenomena and diffusion processes in polymers. Since a quantitative definition of free volume is not possible, a new concept called available volume is introduced. A simple geometric definition of available volume, r...

Viscoelasticity of dilute solutions of semiflexible polymers.

We show using Brownian dynamics simulations and theory how the shear relaxation modulus G(t) of dilute solutions of relatively stiff semiflexible polymers differs qualitatively from that of rigid rods. For chains shorter than their persistence length, G(t) exhibits three time regimes: At very early times, when the longitudinal deformation is affine, G(t) approximately t(-3/4). Over a broad inte...

Mesoscopic theory of the viscoelasticity of polymers.

We have advanced our previous static theory of polymer entanglement involving an extended Cahn-Hilliard functional, to include time-dependent dynamics. We go beyond the Gaussian approximation, to the one-loop level, to compute the frequency dependent storage and loss moduli of the system. The four parameters in our theory are obtained by fitting to available experimental data on polystyrene mel...

Viscoelasticity of Biopolymernetworks and Statistical Mechanics of Semiflexible Polymers