PDMS Thin-Film Composite Membranes with Superior Antiswelling via Covalent Interfacial Engineering

Thin-film composite (TFC) membranes are increasingly utilized in the removal of volatile organic compounds, wastewater treatment, and gas separation, but the excessive swelling of selective layer is still a challenge for the stable running of membranes. In this work, we fabricated polydimethylsiloxane (PDMS)/poly(vinylidene fluoride) (PVDF) composite membranes with ultrahigh interfacial strength for boosting the swelling resistance, where the core structure is that the methacrylic acid modified PVDF can be copolymerized with vinyl-terminated PDMS. The resulting membrane showed an ultrahigh critical load of 58.41 mN for selective layer failure, 2.97 times that of the pristine PDMS/PVDF membrane without covalent interaction. Additionally, the anti-swelling was further evaluated in four solvents, where the resulting membrane achieved a swelling degree of 3.8% in tetrahydrofuran, a reduction of 86.8% compared with the conventional membrane. Benefited from this robust structure, the membrane exhibited stable operation for 120 h at 60 °C with an average separation factor of 10.9 and a flux of 1582 g m –2 h –1 for 5 wt % ethanol/water pervaporation. This strategy offers a new idea to develop more anti-swelling TFC membranes used in various solvent environments.