Order-Disorder and Order-Order Transitions in Smectic C~* Liquid Crystalline Diblock Copolymers

摘要

Block copolymers containing side-chain liquid crystalline (LC) moieties enable materials to have a combination of polymeric and liquid crystalline properties. If the two blocks are incompatible, microphase segregation can occur resulting in isolated LC and amorphous domains. We are interested in how LC ordering overlaps with block copolymer microstructure. A series of diblocks with an amorphous, polystyrene block and a methacrylate based side-chain LC block were prepared. Room temperature and morphological phase diagrams were evaluated using a combination of SAXS and TEM, and microstructure transitions were identified using SAXS at elevated temperatures. These results are compared to LC transitions studied with microscopy and calorimetry. The LC phase effectively changes the Flory-Huggins interaction parameter. Effort is also being made to model the observed transitions and to optimize electro-optic responses.