Thermal diffusion in a polymer blend

Abstract

This contribution presents a thermodynamically sound approach to model temperature sensitive diffusion in multi-phase solids. In order to describe the phenomena of thermal diffusion (thermophoresis) and to simulate the effect numerically, an extended version of the Cahn-Hilliard phase-field model is combined with the heat-diffusion equation. The derived model is formulated consistently with the basic laws of thermodynamics. Its discretized version is embedded in a NURBS-based finite element framework. Numerical simulations and a comparison to experimental results show the effect of thermal diffusion, induced by non-uniform and non-steady temperature fields, on the microstructural evolution of a binary polymer blend consisting of polydimethylsiloxane and polyethylmethylsiloxane.