The research group of Yu Haifeng, University of Technology, has made progress in the construction of multilevel microstructure of liquid crystal and polymer composite materials and photoregulation

[Summary Description] The multilevel microphase structure of liquid crystal and polymer composite materials has a potential application prospect in the fields of nano-template, nano-printing and information anti-counterfeiting, and has been widely concerned by researchers in recent years. Due to the stimulation-response properties of liquid crystal elements, the introduction of liquid crystal as a functional group into block copolymers can make it possible to prepare and regulate large-scale structured nanostructures.

The multilevel microphase structure of liquid crystal and polymer composites has a potential application prospect in the fields of nano-template, nano-printing and information anti-counterfeiting, and has been widely concerned by researchers in recent years. Due to the stimulation-response properties of liquid crystal elements, the introduction of liquid crystal as a functional group into block copolymers can make it possible to prepare and regulate large-scale structured nanostructures. However, there are still some difficulties in the study of multi-level micro and nano structures of liquid crystal and polymer composites. First, with the development of nanotechnology, nanoscience has a more urgent demand for nanodevices with more complex and fine structures. Therefore, the construction of multi-level nanostructures has become a research difficulty and research hotspot in the field of polymer composites. Second, it is still a challenge to achieve rapid, reversible and accurate regulation of the above complex nanostructures at room temperature. Recently, the research group of Yu Haifeng of the School of Engineering of Peking University proposed corresponding solutions to the above two problems.

Based on previous work, the urea bond was introduced into a liquid crystal block copolymer containing azobenzene liquid crystal unit. In the process of microphase separation, the urea bond can form hydrogen bond with the dispersed phase and continuous phase of the liquid crystal block copolymer. The combination of supramolecular bond and the inhibition of each block in the block copolymer affects the crystallization process of the dispersed phase components when cooling from isotropic temperature to room temperature during annealing, thus obtaining a phase domain in which the amorphous and crystalline regions coexist. In the absence of any doping, the research team only used the hydrogen bond between the liquid crystal and the polymer itself, and achieved the construction of nanostructures with a size of less than 10 nm. The work is published in Macromolecular Rapid Communications.