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 hydroca rbon chains in an alternating sequence. Liquid-crystalline behavior wa s investigated by optical microscopy, DSC, and X-ray diffraction. The liquid-crystalline phase appears to be smectic B from X-ray data. Inte resting differences in the mesophase transition temperatures are obser ved along the series, the polymers showing an odd-even effect in the i sotropization temperatures as the length of the hydrocarbon is changed . Differences are also seen in layer spacing from X-ray data, which sh ows some alternation as the hydrocarbon content increases but is gener ally much smaller than the expected extended repeat unit length. We di scuss these in relation to the lengths of the segments.