Self-assembled vertical alignment layer of bifunctional amphiphiles for fast electro-optical switching of nematic liquid crystals

We present a novel homeotropic alignment method that simultaneously improves the ability of vertical alignment and fast switching of liquid crystals (LCs) in the electro-optical performance. The proposed method utilizes dual self-assembly of 4-(4-heptylphenyl)benzoic acid and 2-carboxyethyl acrylate via hydrogen bonding with ITO substrate. The 4-(4-heptylphenyl)benzoic acid composed of aromatic moieties and alkyl chains induce the homeotropic alignment of the LC molecules. Photopolymerization of 2-carboxylethyl acrylate with a reactive acrylate group under UV irradiation gives the LC molecules a fast response. Our proposed alignment method allows for fabrication of LC devices exhibiting fast LC switching without a conventional polyimide layer.