SEMIFLUORINATED POLYMERS .1. SYNTHESIS AND CHARACTERIZATION OF SIDE-CHAIN LIQUID-CRYSTALLINE POLYMERS CONTAINING SEMIFLUORINATED OLIGOOXYETHYLENE BASED FLEXIBLE SPACERS

The synthesis and characterization of polymethacrylates, polyacrylates and polysiloxanes containing 4-methoxy-4'-hydroxybiphenyl (4-BP), 4-methoxy-4'-hydroxy-alpha-methylstilbene (4-MS) and 4-hydroxy-4'-methoxy-alpha-methylstilbene (4'-MS) mesogenic groups and a semifluorinated triad based on tetrafluoro-oxetane, hexafluoropropylene oxide and trifluoroethylene oxide is described. All polymers display a S(A) mesophase and side chain crystallization. In the case of polymers based on 4-MS and 4'-MS the highest degree of decoupling seems to be displayed by the polymethacrylates. This result is in contrast to the behaviour of the corresponding polymers containing aliphatic spacers. The polymethacrylate based on 4-BP displays an unusual 'inverse' monotropic S(A) mesophase which to our knowledge was not previously encountered in any liquid crystal systems. The synthesis and characterization of copolymethacrylates and copolysiloxanes containing 4-methoxy-4'-hydroxy-alpha-methylstilbene and 4-hydroxy-4'-methoxy-alpha-methyl-stilbene constitutional isomers is also described.