Preparation, characterization, and permeation property of a liquid crystal/PDMS membrane material

摘要

By introducing the ordered and flowing liquid crystalline groups into polymeric membranes, a novel liquid crystal/polydimethylsiloxane (LC/PDMS) membrane material is synthesized with PDMS containing vinyl group, polymethylhydrosiloxane and cholesteric LC as matrix materials. The chemical structure, LC behaviors and mechanical performance of the LC/PDMS crosslinked membranes are characterized by using FTIR, differential scanning calorimetry (DSC), and polarized light microscopy with a hot stage. Some factors on permeability and permselectivity for carbon dioxide and nitrogen gas are also examined. These results suggest that the membrane-forming property and permeation properties of the crosslinked membranes are obviously enhanced due to the introduction of the LC groups into PDMS and crosslinking reaction in the preparation process. At pressure difference of 0.1 MPa and testing temperature of 40°C, the permeability coefficient for carbon dioxide and ideal separation factor for carbon dioxide and nitrogen are up to 4667 Barrer and 24.0, respectively. In addition, the incorporation of LC containing unsaturated linkage has the potential for further modification reactions such as grafting and crosslinking.