Fluorinated mesogen-jacketed liquid-crystalline polymers as surface-modifying agents: Design, synthesis and characterization

Full Paper: Monomers with semifluorinated tails on monomeric vinyl hydroquinone cores were synthesized and their polymerization behavior was examined. The resulting semifluorinated mesogen-jacketed liquid-crystalline polymers (MILCPs) proved to form fairly hydrophobic surfaces with water contact angles of 110-118degrees. These polymers were studied for the role of the fluorinated groups on both liquid-crystalline (LC) and behavior and surface properties. Initial surface stability studies showed that these fluorinated MJLCP surfaces are relatively more stable than comparable systems of side-chain fluorocarbon LC blocks. Our studies show that M(I), 2,5-bis[(10-perfluorohexyl-decanoly)oxy]styrene, could not be homopolymerized, while M(2) incorporating benzoate groups, 2,5-bis[4(10-perfluorohexyl-decayloxy)-benxyloxy]styrene, permitted facile homopolymerization and block copolymer preparation by stable free-radica polymerization. As determined by wide-angle X-ray diffraction, the S-C-N transition temperature of the block copolymer shifted to a higher temperature with an increase in the DP of M(2). NEXAFS studies showed no net orientation of the (CF2)(n)-side chains towards the surface normal consistant with observed low order smecitc phases, nevertheless pointed to the presence of fairly hydrophobic CF2-covered surfaces.