Deformations of glassy polymers in very low temperature regime within cylindrical micropores

TL;DR

This paper investigates the deformation behavior of glassy polymers in cylindrical micropores at very low temperatures, revealing near frictionless deformation fields influenced by surface roughness, slip, and shear thinning effects.

Contribution

It introduces a transition-rate-state model considering shear thinning and surface roughness to analyze low-temperature deformation in micropores, providing new insights into the kinetics under confinement.

Findings

Deformation can be nearly frictionless due to shear stress vanishing.

Surface roughness and slip significantly affect deformation kinetics.

Deformation kinetics depend on temperature, activation energy, shear rate, and surface conditions.

Abstract

The deformation kinetics for glassy polymers confined in microscopic domain at very low temperature regime was investigated using a transition-rate-state dependent model considering the shear thinning behavior which means, once material being subjected to high shear rates, the viscosity diminishes with increasing shear rate. The preliminary results show that there might be nearly frictionless fields for rate of deformation due to the almost vanishing shear stress in micropores at very low temperature regime subjected to some surface conditions : The relatively larger roughness (compared to the macroscopic domain) inside micropores and the slip. As the pore size decreases, the surface-to-volume ratio increases and therefore, surface roughness will greatly affect the deformation kinetics in micropores. By using the boundary perturbation method, we obtained a class of temperature and activation energy dependent fields for the deformation kinetics at low temperature regime with the presumed small wavy roughness distributed along the walls of an cylindrical micropore. The critical deformation kinetics of the glassy matter is dependent upon the temperature, activation energy, activation volume, orientation dependent and is proportional to the (referenced) shear rate, the slip length, the amplitude and the orientation of the wavy-roughness.