Directed Self-Assembly of Liquid Crystalline Block Copolymers – Microstructural Control of Functional Materials

Block copolymer (BCP) microphase separated domains are a convenient host for liquid crystalline (LC) mesophases. The confinement provided by the block copolymer microstructure can be tailored to ensure the production of LC monodomains which are attractive as thermo-optic and electro-optic functional materials. However, large-area control over the block copolymer microstructure is difficult to achieve and undermines the potential of these materials for device applications. We outline strategies for the control of both LC and BCP morphology in these hybrid materials and demonstrate well controlled orientation on dual structure length scales by application of oscillatory shear and through the use of high magnetic fields in the melt state. The concurrent alignment of LC and BCP structure is strongly governed by the anchoring condition of the LC mesophase at the block copolymer inter-material dividing surface, resulting in the appearance of a novel, temperature dependent BCP morphology in one case.

Keywords: Block copolymers; liquid crystals; morphology; functional materials; microstructure;