Molecular dynamics simulations have been carried out on fully atomistic models of amorphous polymers. Both bulk structures and thin films were simulated for a wide range of thermoplastics such as PS, PMMA, poly (phenylene-ether) (PPE), poly (etherimide) (PEI). The influence of molecular weight and functional end-groups was investigated. The comparison between “bulk” and “surface” models clearly shows the increase of molecular mobility and a strong decrease in density at the vicinity of free surfaces. Simulated surface tensions, computed by different methods, are generally overestimated as compared to the experimental ones.
PVT (Pressure-Volume-Temperature) measurements have been conducted, as another method to compute physical properties of amorphous polymers. From such measurements, cohesive energy densities, interaction parameters, and then interfacial properties, were obtained for various thermoplastics and the corresponding incompatible melts. Such a tool could be used for designing polymer surfaces and interfaces in polymer blends.