Uniaxial alignment of ZnO nanowires via light-induced directional migration of azopolymeric microspheres

The photo-responsive properties of azopolymers have attracted significant attention due to their vast potential for use in a broad range of applications. Upon exposure to light, azopolymers undergo reversible trans-cis isomerization, which results in mass transport in the polymer matrix. Harnessing this photofluidization process, we explored the feasibility of utilizing azopolymers as a director to align one-dimensional (1D) nanomaterials. Azopolymer nanocomposite microparticles containing ZnO nanowires (NWs) were microfluidically synthesized and illuminated with a linearly polarized laser with varying exposure times. Upon gradual anisotropic reconfiguration of the azopolymers, uniaxial alignment of the internally stored NWs with an axial ratio greater than ten was successfully attained along the direction of polarized light. This result demonstrates the prospect of using the photo-induced mass migration of azopolymers for non-invasive manipulation of nanomaterials for various optical or electronic device applications.