Membrane surfaces can be modified for various applications The use of liquid solvents in membrane coating processes often creates a blanket coating in which the pores are clogged due to surface tension problems and wettability. These problems do not exist for vapor deposition processes and therefore can be used to conformally coat substrates with complex geometries such as membranes. Initiated chemical vapor deposition (iCVD) is a low energy vapor deposition process (0.01 W/cm~2) that can be used to produce linear polymers in which the pendant chemical moities are kept intact. iCVD has been used to polymerize a wide variety of vinyl monomers such as glycidyl methacrylate and 2-hydroxyethyl methacrylate. Deposition rates as high as 200 nm/min have been achieved using iCVD. The proposed polymerization mechanism is the classical free radical polymerization mechanism of vinyl monomers. Monomer and initiator gases are fed into a vacuum chamber where resistively heated wires are used to thermally decompose the initiator molecules into free radicals. The free radicals then attack the vinyl bonds of the monomer molecules. Propagation occurs on the surface of a cooled substrate. Recently, the iCVD technique has been used to conformally coat the fibers of electrospun polymer mats with hydrophobic fluoropolymer. The goal of this study is to use the iCVD process to coat the surfaces of polymeric membranes. These membranes have monodisperse pore distributions and vary in porosity, length, and diameter. iCVD is being used to coat these membranes with a low surface energy (10 mN/m) polymer that renders the membranes both hydrophobic and oleophobic.
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