Photoinduced mass transfer behavior of azo polymers has aroused extensive research interest in recent years

which involves a series of basic scientific problems about light-matter interactions and promising application prospects. Azo polymer microspheres can act as a unique type of isolated deformation unit to show photoinduced mass transfer behavior. The research in this area not only offers a novel method for the preparation of shape-anisotropic particles through photoinduced shape-manipulation

but also provides a valuable tool for studying the complex multi-scale motions of photoinduced mass transfer behavior. This article presents and summarizes the progresses in the photoinduced mass transfer and deformation of azo polymer microspheres in recent years. The deformation behavior and its intrinsic mechanism of azo polymer microspheres under different conditions are comprehensively discussed. A perspective of the future research and applications in this field is also presented.