Opalescent Cholesteric Networks from Chiral Polyisocyanates in Polystyrene

The cholesteric polymer films described here, i.e., the “locked in” chiral nematic phase of polymer liquid crystals, have several advantages as materials for optical applications. The Figure shows schematically a cholesteric network based on a chiral isocyanate terpolymer in styrene in which the cholesteric liquid-crystalline structure is “locked in” by photopolymerization.