Green fabrication of pervaporation membranes via UV-curing for polar/non-polar solvents separation

A solvent-free photopolymerization method was employed to fabricate pervaporation membranes to separate polar/non-polar organic solvent mixtures. Commercially available monomers bis[2-(3,4-epoxy cyclohexyl)ethyl] tetramethyldisiloxane (TMDG) and 3,3'-(Oxybis(methylene))bis(3-ethyloxetane) (DOX), along with a photo-initiator, were mixed and spin-coated onto the PVDF membranes surface, followed by UV-curing to form polyether-polysiloxane coatings. This approach eliminates the use of organic solvents, offering a simple, efficient, and cost-effective process with significant economic and environmental benefits. Precise control over the coating structure and polarity was achieved by adjusting the monomer ratios. Among these composite membranes, M3 demonstrated excellent permeability and separation efficacy for the pervaporation of polar/non-polar mixed organic solvents. At 45 °C, the flux of M3 to acetone/n-hexane (5 wt %/95 wt %) and methanol/n-hexane (5 wt %/95 wt %) were 615 and 559 g m −2  h −1 , respectively, and the separation factors were 836 and 798, respectively. Moreover, M3 also exhibited an excellent separation effect on acetone / n-hexane azeotropes (59 wt % / 41 wt %, 49.8 °C), with a flux of 1806 g m −2  h −1 and a separation factor of 121. Ultimately, M3 maintained stable permeability and separation performance for acetone/n-hexane (5 wt %/95 wt %) throughout 168 h, demonstrating the outstanding chemical stability of the coating prepared by UV-curing.