New arylidene-siloxane polyethers: Liquid-crystalline and photosensitive properties

By polycondensation reactions, starting from alpha, omega-bis(chloromethyl)polydimethylsiloxanes with different molecular weights and 2,6-bis(4-hydroxybenzylidene)cyclohexanone, new polyethers were obtained. The structure of resulting polymers was confirmed by IR and H-3-NMR spectroscopy and their thermal properties and mesophase behavior were studied by TGA, DSC, and polarizing light microscopy. Depending on the length of the siloxane spacer, some of the obtained compounds exhibited thermotropic liquid-crystalline properties. A possible smectic texture was investigated by X-ray diffraction measurements at room temperature. A decrease of the transition temperatures values was observed as the spacer length increased. The photochemical behavior of the siloxane polyethers was studied by ultraviolet absorption spectroscopy. (C) 2003 Wiley Periodicals, Inc.