Photocontrollable liquid-crystalline block copolymers: design, photo-directed self-assembly and applications

Photocontrollable liquid-crystalline block copolymers have exhibited remarkable light-response properties, due to their unique features elegantly combining mesogenic ordering with microphase-separated nanostructures. Their exceptional optical characteristics make them excellent candidates for ever-increasingly widespread applications, especially, in the area which is utilized for nanopatterns. However, their unsatisfactory structure design and performance have limited their further potential in those applications. In the last few years, tremendous efforts have been made to improve their capability and performance by elaborating the structural design strategy. Here, we summarize recent progress in various photocontrollable liquid-crystalline block copolymers, including their photoresponsive mechanisms, alignment techniques of microphase-separated nanodomains, and intriguing properties. Critical discussions are given in directed self-assembly, which is a novel bottom-up lithography technology that can be manipulated by actinic light. Additionally, their potential applications in energy storage, holographic gratings, photo-driven actuators, nanotemplates and information storage are comprehensively summarized. Finally, the existing challenges and prospects in this field are discussed.