LIQUID-CRYSTALLINE BEHAVIOR IN FLUOROCARBON HYDROCARBON MICROBLOCK POLYMERS .2.

A series of liquid-crystalline polymers has been synthesized in which the mesogenic perfluoroalkyl chains are directly Linked to the hydrocarbon chains in an alternating sequence. Liquid-crystalline behavior was investigated by optical microscopy, DSC, and X-ray diffraction. The liquid-crystalline phase appears to be smectic B from X-ray data. Interesting differences in the mesophase transition temperatures are observed along the series, the polymers showing an odd-even effect in the isotropization temperatures as the length of the hydrocarbon is changed. Differences are also seen in layer spacing from X-ray data, which shows some alternation as the hydrocarbon content increases but is generally much smaller than the expected extended repeat unit length. We discuss these in relation to the lengths of the segments.