A Review of PDMS Membrane Fabrication for Use in Pervaporation Experiments

In this work, a series of polydimethylsiloxane (PDMS) composite membranes were fabricated by using vinyl-terminated PDMS with polyhydomethylsiloxane (PHMS) as a cross-linker, with a hydrophobic DeltaMem PERVAPTM 4155-80 support layer, through drawdown casting with a doctor blade. The original goal of the work was to control cross-link density of the membranes by varying the ratio of cross-linker to PDMS, and examining the effect of cross-link density on performance of the membranes under pervaporation. The goal of the work shifted to optimizing the fabrication procedure to produce usable membranes after initial attempts at fabrication were unsuccessful. It was found that viscosity of the polymer solution, heating time, degassing time, and the application of the support layer played key roles in determining the success of the membrane fabrication. No usable membranes were fabricated and pervaporation data was not collected, but many insights were gained into the process of membrane fabrication and the different methods that can be used to fabricate PDMS membranes. This work demonstrated the need for further study into alternative methods for membrane fabrication, and key avenues to explore to optimize the process.