A molecular dynamics simulation study to investigate the elastic properties of PVDF and POSS nanocomposites

The effects of the polyhedral oligomeric silsesquioxanes compound (3, 3, 3-trifluoropropyl)(8)Si8O12 (FP-POSS) on the elastic properties of poly(vinylidene difluoride) (PVDF) are investigated using molecular dynamics (MD) simulations. The volume-temperature properties and elastic constants for four different systems (PVDF-0, neat PVDF; PVDF-I, with 3.1 wt% FP-POSS; PVDF-II, with 5.85 wt% FP-POSS; PVDF-III, with 8.52 wt% FP-POSS) in the temperature range 100-400K are studied. Simulation results show that (1) the calculated volume-temperature behavior and elastic constants for PVDF-0 matched well with experimental results; (2) the glass transition temperature of PVDF is significantly improved with FP-POSS; (3) the moduli of PVDF are improved and the improvement effect, in general, nearly always decreases with the increase in the mass ratio of FP-POSS. Furthermore, the possible mechanism of the difference in the modulus improvement effects is discussed.