Regulating Pore Intrusion in PDMS/PSF Composite Membrane Formation for Enhanced O2/N2 Separation

Although pore intrusion can cause defects in the selective layer, it can improve the interface adhesion between the selective layer and the support layer. Consequently, a novel strategy for a controlled pore intrusion depth has been proposed for the first time. In this work, pore intrusion was regulated by the addition of glycerol, DI water, or paraffin oil as a prewetting agent to a support to prepare poly(dimethylsiloxane) (PDMS)/polysulfone (PSF) composite membranes. We found that the pore intrusion depth was proportional to the curing rate of PDMS. The prewetting agent demonstrated a greater affinity for the support, and a high boiling point was beneficial in alleviating pore intrusion. The properties of the support could affect the gas permeance. The PDMS/PSF composite membrane with different pore intrusion depths could be prepared by changing the extraction time of the support. This strategy would provide a reference for studies on defect-free PDMS composite membranes.