An Advanced Method for Preparation of Helical Carbon and Graphitic Films Using a Carbonization Substrate

An advanced method is proposed to prepare helical graphite films with large domains of left- and right-handed spiral morphologies which are composed of fibril bundles using oxidized PEDOT films as carbonization substrates. Helical PEDOT (H-PEDOT) films, as carbonization precursors, are prepared via an electrochemical polymerization in an asymmetric reaction solution containing the chiral nematic liquid crystal (N*-LC), the monomer bis-EDOT, and an electrolyte. The N*-LCs are provided by mixing a spot of di- or tetra-substituted, axially chiral, binaphthyl compounds as the chiral dopants with the N-LC. In addition, a new type of chiral dopant bearing a cyanobiphenyl moiety, which is the same mesogenic core as that of the parent LC [4-cyano-4′-pentylbiphenyl], is used for preparing high miscible N*-LC systems. The distances between the fibril bundles of H-PEDOTs specifically depend on the helical twisting powers of the chiral dopants. In circular dichroism spectra, the H-PEDOTs in both neutral and oxidized ...