Molecular modeling of temperature dependence of solubility parameters for amorphous polymers

A molecular modeling strategy is proposed to describe the temperature (T) dependence of solubility parameter (delta) for the amorphous polymers which exhibit glass-rubber transition behavior. The commercial forcefield "COMPASS" is used to support the atomistic simulations of the polymer. The temperature dependence behavior of delta for the polymer is modeled by running molecular dynamics (MD) simulation at temperatures ranging from 250 up to 650 K. Comparing the MD predicted delta value at 298 K and the glass transition temperature (T (g)) of the polymer determined from delta-T curve with the experimental value confirm the accuracy of our method. The MD modeled relationship between delta and T agrees well with the previous theoretical works. We also observe the specific volume (v), cohesive energy (U (coh)), cohesive energy density (E (CED)) and delta shows a similar temperature dependence characteristics and a drastic change around the T (g). Meanwhile, the applications of delta and its temperature dependence property are addressed and discussed.