Insight of organic molecule dissolution and diffusion in cross-linked polydimethylsiloxane using molecular simulation

Polymeric membranes have gained an immense importance for the pervaporation (PV) of biofuels. The PV performance is influenced by several complex elements and significant understanding is empirically fairly difficult. Furthermore, it is essential to specify membrane swelling in different solvents prior to the PV. A molecular dynamics simulation protocol was applied to examine the swelling of cross-linked PDMS membranes in 1-butanol, ethanol, acetone, and water, the dissolution of organic molecule in dilute aqueous solution in PDMS, the PV through these swollen membranes and dissolution rate of guest molecules in membranes. The agglomeration effects of water as well as organic molecules inside cross-linked PDMS membrane during sorption and diffusion processes were also investigated. The effects of predicted cross-linked PDMS on separation performance of membranes, interactions of the guest molecules on the swelling degree and diffusion coefficients follow the experimental trend. The predicted dissolution and diffusion, the diffusion selectivity and mean square displacement of different agglomerated forms of water and alcohol molecules through cross-linked membrane fairly matches the reported experimental results. Moreover, their reliability on the interaction between solvent and polymer, void size distribution and temperature were investigated. The micro level insights into the swelling of cross-linked polymer membranes, dissolution and diffusion of organic molecules and understanding of mass transfer were provided by simulation, which are valuable for making new membranes for high PV performance.