On April 17th, the reporter learned from the University of Science and Technology of China that Professor Peng Chenhui's team from the School of Physics of the university used the synergistic effect of light driving azobenzene molecules to induce collective motion and rearrangement of liquid crystal molecules, while triggering the spatiotemporal evolution of nematic lines, thus achieving collective transfer and reconfigurable self-assembly of colloidal particles. The research results were recently published in the Journal of the American Academy of Sciences. Liquid crystal is a type of anisotropic material with molecular orientation and long-range order, which has wide applications in fields such as display, sensing, and photonic devices. The research team first utilized a self built device to control the machine arrangement of azobenzene molecules through a pre designed approach, thereby controlling the self-assembly of liquid crystal microstructures and preparing a programmable controlled dislocation line network. Under the action of light driving, the synergistic effect of azobenzene molecular machines causes changes in the orientation of liquid crystal microstructure molecules on the substrate surface, leading to changes in the group dynamics morphology of the internal dislocation network of the sample. If colloidal particles are placed in a system far from equilibrium, they can be flexibly picked up, transported, and reassembled as the optical drive moves towards the deformation of the dislocation network. Moreover, the collective transportation and recombination of colloidal self-assembly can also be achieved by controlling the polarization direction of the irradiation light, controlling the direction and mode of their transportation, such as translation, clockwise or counterclockwise rotation, thus achieving programmable self-assembly of micron scale colloidal particles. During the research process, the research team also clarified how the pre designed topological defects control the motion mechanism of colloidal particles on the dislocation line, which is determined by the elastic properties of the local pre designed unfolding and bending deformation of the liquid crystal. Therefore, the physical mechanism of this light driven programmable colloidal self-assembly lies in the synergistic recombination of nanoscale molecular machines through illumination, and the control of changes in the orientation of nanoscale liquid crystal molecules through the interaction between molecular machines and liquid crystal molecules. Due to the long-range ordered nature of liquid crystal molecules, it triggers changes in the orientation of surface macroscopic liquid crystal molecules. This macroscopic change further drives the changes in the internal liquid crystal microstructure of the sample through surface anchoring, thereby achieving the reconstruction of macroscopic scale dislocation line networks and colloidal self-assembly. The researchers stated that this study not only elucidates how to use pre designed topological defects and dislocation line networks far from equilibrium to control programmable colloidal self-assembly, but also opens up new directions for the design of intelligent composite materials. (New News Agency)