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Fluorinated mesogen‐jacketed liquid‐crystalline polymers as surface‐modifying agents: Design, synthesis and characterization
Author(s) -
Gopalan Padma,
Andruzzi Luisa,
Li Xuefa,
Ober Christopher K.
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(200207)203:10/11<1573::aid-macp1573>3.0.co;2-z
Subject(s) - mesogen , copolymer , polymer , polymer chemistry , monomer , mesophase , materials science , contact angle , polymerization , styrene , side chain , liquid crystal , radical polymerization , chemical engineering , chemistry , composite material , liquid crystalline , optoelectronics , engineering
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 (MJLCPs) proved to form fairly hydrophobic surfaces with water contact angles of 110–118°. These polymers were studied for the role of the fluorinated groups on both liquid‐crystalline (LC) 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(1) , 2,5‐bis[(10‐perfluorohexyl‐decanoyl)oxy]styrene, could not be homopolymerized, while M(2) incorporating benzoate groups, 2,5‐bis[4‐(10‐perfluorohexyl‐decanyloxy)benzyloxy]styrene, permitted facile homopolymerization and block copolymer preparation by stable free‐radical 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 (CF 2 ) n side chains towards the surface normal consistent with observed low order smectic phases, nevertheless pointed to the presence of fairly hydrophobic CF 2 ‐covered surfaces. The above evidence proved the materials are suitable for application as surface‐modifying agents.Polarized optical micrograph of M(1) showing a mosaic texture due to a smectic mesophase obtained on slow cooling at 2 K min −1 from the isotropic phase.