Thermodynamic properties of poly(vinyl alcohol) with different tacticities estimated from molecular dynamics simulation

We used molecular dynamics simulation together with the OPLS-AA force field along with a high temperature equilibration protocol proposed by Belmares et al. to calculate selected thermodynamic properties of poly(vinyl alcohol) (PVA) with different tacticities. The results showed that the OPLS-AA force field was able to reproduce specific volumes, thermal expansion coefficients, glass transition temperatures and solubility parameters of the PVAs over a wide range of temperatures (200–550 K). PVA with different tacticities in the amorphous phase showed different solubility parameters but possessed similar specific volumes, thermal expansion coefficients and glass transition temperatures. For heat capacities, 300% overestimations were obtained. Such overestimations were reduced significantly to about 30% by applying the quantum correction method of Berens et al. We have also applied the newly developed two-phase thermodynamic (2 PT) approach in an attempt to further improve the results but failed.