Bulk and interfacial studies of a new and versatile semifluorinated lyotropic liquid crystalline polymer

This study introduces the phase diagram and interfacial characteristics of a novel lyotropic polymeric liquid crystal. The polymer consists of an α-methylstilbene mesogenic group bridged by a low interfacial energy perfluorocyclobutyl ring via flexible aryl ether linkages. The polymer, obtained by thermal cyclopolymerization of trifluorovinyl ether monomers, forms lyotropic lamellar mesophases over a wide range of temperatures and molecular weights. Mesophase behavior probed by optical microscopy, AFM, NMR, and X-ray scattering is detailed. The lamellae consist of longer chains, immersed in a solvent of smaller chains. The interfacial characteristics of these lyomesophases are affected by the low surface energy moiety. At the interface with glass, homeotropic alignment is observed. When cast into thin films, an additional periodicity on the nanometer scale has been detected. Thin films consist of spontaneously oriented bundles with characteristic length scale on 50 nm.