Helical Network Polymers Serving as Chiral Templates for Asymmetric Photo-Cross-Link Polymerizations

First-generation helical network polymer (HNP-1) films bearing phenylcyclohexyl (PCH) mesogen-based moieties were synthesized through the photo-cross-linking polymerization of acrylate derivatives in chiral nematic liquid crystals (N*-LCs) used as asymmetric polymerization solvents. The HNP-1 films were stable in organic solvents, and their helical structures were undestroyed; therefore, they gave rise to an N*-LC phase when N-LCs were added onto the surface of the HNP-1 films. Then, the HNP-1 films were used as chiral templates that enabled subsequent photocross polymerization processes in N*-LCs. Second-generation HNP (HNP-2) films were synthesized via the photo-cross-linking polymerization of functionalized acrylate derivatives bearing bis(1,1′-biphenyl)fluorene-based moieties. The HNP-2 films showed fingerprint morphologies resembling those of the HNP-1 films and exhibited circular dichroism in terms of absorption and circularly polarized luminescence with high dissymmetry factors on the order of 10–2. The HNP-1 films serve as chiral templates for the synthesis of other types of HNP films through photocross polymerizations that are free from chiral dopants.