Preparation of PVMS-b-PMMA Block Copolymer with Potential for Oil-Water Separation

Several years ago, the oil spill in the Gulf of Mexico resulted in great degradation of the environment. Additionally, it opened up discussion on effective methods of purifying oil and water in case of a similar incident occurrence. Membrane technology serves this purpose, and development of effective membranes includes careful material selection to achieve certain properties such as: (1) high-throughput of either oil/water, (2) prevention of fouling (3) great selectivity (4) mechanical strength. We herein report synthesis of poly(vinylmethylsiloxane-block-methyl methacrylate) (PVMS-b-PMMA) by a combination of anionic synthesis of PVMS, ATRP of PMMA, and then co-joining the end-group functionalized blocks with a click reaction. In using this combination of methods, we are able to effectively control both molecular weight and polydispersity in polymers that were otherwise challenging to synthesize by sequential block addition. Following thin film nanostructure alignment by solvent annealing, exposure to UV light cross-links the siloxane copolymer block, which imparts mechanical integrity, and degrades the sacrificial PMMA block in a single step to produce a nanoporous film. Morphology of the block copolymer was studied by both atomic force microscopy and scanning electron microscopy. The hydrophobicity and nanoporosity of these films are desirable characteristics for their application as nanoporous membranes for oil/water separation.