MICROPHASE-STABILIZED FERROELECTRIC LIQUID-CRYSTALS (MSFLC) - BISTABLE SWITCHING OF FERROELECTRIC LIQUID CRYSTAL-COIL DIBLOCK COPOLYMERS

A side-chain liquid crystal (LC) block copolymer with a ferroelectric smectic C LC block has been shown to exhibit bistable switching behav ior in electric fields. Ferroelectric switching was demonstrated for b lock copolymers with volume fractions of 0.58 and 0.52 Liquid crystal block. SAXS and TEM showed that the bulk morphologies of these two mat erials were hexagonally packed minority amorphous polystyrene (PS) cyl inders and alternating lamellar amorphous PS layers, respectively. Cro ss-sectional TEM of a 10 mu m thick film of the 0.58 volume fraction l iquid crystal material used for the optical switching studies showed t he cylinders to be well aligned along the shear direction and orthogon al to the applied electric field direction. It is believed that switch ing is possible due to an unwinding of the pitch of the smectic C pha se due to the presence of the intermaterial dividing surface of the mi crophase-separated cylindrical domains of the block copolymer which sp atially confine the mesophase. This interaction realizes the concept o f a microphase-stabilized ferroelectric liquid crystal (MSFLC) device.