Discussion of Rod-Coil Systems

Due to the conformation asymmetry in rod-coil diblock copolymer systems, the packing is expected to be totally different from conformationally symmetric coil - coil block copolymers. Semenov and Vasilenko [71] have predicted that a N-SmA transition can be either a first-order transition (in the case of large coil fraction) or a second-order transition (in the case of small coil fraction) and a SmC phase in a rod-coil system is also expected for f 036. 

Later Halperin [60, 69] predicted that the lamellae are expected to exhibit a tilting, SmA-SmC first-order phase transition which is driven by the competition between the surface and deformation free energies. 

All the above theories are based on geometric considerations. By applying self-consistent field theory, Miiller and Schick [74] have predicted that the only thermodynamically stable morphologies for rod-coil systems are those with the coils on the convex side of the interface. Very recently Gurovich [75] developed a statistical theory which treats the microphase separation in LC block copolymer melts near the spino-dal and predicts orientational and reorienta-tional phase transitions driven by the configurational separation and four different phases. 

The study of the SHIC rod-coil system offers an excellent model system for testing existing theories and opens routes to a new world of materials which combine aspects of liquid crystals, statistical physics, and. solid-state physics. 

4 Block Copolymers Containing Liquid Crystalline Segments 

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