Chiral 3D porous hybrid foams constructed by graphene and helically substituted polyacetylene: preparation and application in enantioselective crystallization

This study reports the first strategy for establishing chiral 3D porous hybrid foams constructed by optically active helical-substituted polyacetylene and reduced graphene oxide (RGO). Firstly, RGO-foam was prepared from graphene oxide through a reduction/self-assembly process, and then adsorbed monomer, cross-linking agent, and catalyst. After polymerization, cross-linked helical polymer chains formed inside the RGO-foam, providing chiral 3D foams. Circular dichroism spectra verified the formation of helical polymer chains with preferential helicity and considerable optical activity of the chiral 3D foams. Their porous structure was observed by SEM. TGA and BET analyses demonstrated the foams' remarkable thermostability and high specific surface area. The chiral foams were used as additive to induce enantioselective crystallization of racemic alanine. L-Alanine was preferentially induced to form needle-like crystals. The chiral foams could be easily separated and reused. This study provides a novel type of chiral hybrid materials with significant potential applications in chiral-related areas.