Polydimethylsiloxane/liquid crystal cross-linked membranes: Preparation, characterization and oxygen transport properties

The introduction of liquid crystals (LCs) has presented an interesting approach to improving gas separation properties in polymeric membranes. A novel polydimethylsiloxane (PDMS)/LC cross-linked membrane was prepared with PDMS containing vinyl groups and LCs containing unsaturated linkages as matrix materials. The chemical structures and LC properties were characterized with FTIR, DSC and thermal polarized optical microscopy. Some influential factors that affect the permeability and transport properties were also studied. The results showed that the membranes exhibited good transport properties. The oxygen permeability coefficient and oxygen/nitrogen separation factor were as large as 789 Barrer and 3.40, respectively. The transport properties of the membrane are significantly larger than those of Robeson's upper bound. Compared with modified PDMS membranes, the cross-linking method and the introduction of LCs are simple and convenient, and the transport properties are also enhanced.