Thermodynamically consistent random phase approximation for compressible multicomponent mixtures

Abstract

• Thermodynamically consistent version of the random phase approximation is developed. • The total structure factor, equation of state and density correlation length of the multicomponent polymer blend is obtained. • The calculated structure factor of ternary polymer blend is shown to be in good agreement with the small angle neutron scattering experiments. We develop a thermodynamically consistent version of the random phase approximation for multicomponent mixtures. The developed approach makes it possible, in particular, to accurately take into account the free volume effect on the entropy of mixing and steric interactions between the molecules. Further, we apply the developed theory to derive the total structure factor, equation of state and density correlation length of a multicomponent polymer blend. We demonstrate that the developed theory adequately reproduces the results of the small angle neutron scattering experiments for the structure factor of the investigated ternary polymer blend.