Simulation study on the relationship between the crosslinking degree and structure, hydrophobic behavior for poly (styrene-co-divinylbenzene) copolymer

Molecular dynamics (MD) and Grand Canonical Monte Carlo (GCMC) simulation were employed to investigate the relationship between the crosslinking degree and structure, hydrophobic behavior for poly (styrene-co-divinylbenzene) （P(S-DVB)）copolymer. The structure properties of P(S-DVB) with different crosslinking degree were evaluated by density, fractional free volume (FFV) and glass transition temperature (Tg). The magnitude of the hydrophobicity of P(S-DVB) polymer was quantitatively assessed by solubility parameter, surface energy, interfacial interaction of P(S-DVB) coating-water system and adsorption isotherms. The simulation results identically showed its hydrophobicity decreased with the increase of crosslinking degree. Moreover, the free energy of interaction between the copolymer and water molecule (ΔGiwi) is −83.80 mJ/m2 (5%), −80.32 mJ/m2 (10%) and −75.60 mJ/m2 (15%), respectively, further indicating its strong hydrophobicity. Quantitative analysis of the contribution for the potential energy to the surface energy revealed that the van der Waals energy was the major contribution component.