Effects of Electric Fields on Lamellar Structures of Liquid-Crystalline Block Copolymers

We investigate the electrically induced lamellar contraction in microphase separated liquid-crystalline diblock copolymer using the phase field-crystal model. We demonstrate that collective rotations of the constituents liquid-crystal molecules relative to the layer normal can lead to unusually large changes of the lamellar spacing. We also demonstrate that the orientational order of the constituent liquid-crystals can accelerate microphase separation and can also lead to fast dislocation motion. Our results are directly relevant to the studies of electrically tunable block copolymer photonic crystals with a full color display.