Structure of fluorinated side-chain smectic copolymers:: Role of the copolymerization statistics

Side-chain fluorinated copolymers present very specific wetting and tacking properties that are strongly related to their organization. We have studied the structure of these systems by X-ray scattering in the liquid crystalline regime, as a function of the ratio of fluorinated groups on one hand and of the copolymerization statistics on the other. The structures obtained are always highly ordered and exhibit a smectic B type organization, where the two types of pendant groups are able to crystallize independently. However, packing differences appear for copolymers with different chain statistics due to the existence of microphase separation between the side groups. The roles of these parameters on phase transitions, periodicity, and degree of crystallinity of the polymers are discussed. Their behavior with temperature, important for applications, is also studied.