In-Plane Uniaxial Helical-Axis Alignment in Chiral-Nematic Liquid Crystal Polymer Films Using Photogradient Polymerization

Chiral-nematic liquid-crystal (N* LC) polymer films with uniaxially controlled helical-axis alignments have attracted increasing attention for developing next-generation materials with promising mechanical, optical, and electronic properties. These functionalities in N* LC polymer films can be realized by controlling their helical-axis alignment. However, achieving precise control over helical-axis alignment in polymer films remains challenging. This study presents a simple and effective method for controlling uniaxial helical-axis alignment in polymer films through photogradient polymerization. This approach induces a direction-controlled isotropic-to-N* LC phase transition driven by a polymer concentration gradient, resulting in uniaxial helical-axis alignment along the phase transition direction. The proposed method offers valuable insights for the facile fabrication of N* LC polymer films with controlled helical-axis alignments.