Fabrication and optical properties of self-assembled films with micro needlelike arrays under magnetic field

► The micro needlelike arrays were fabricated by magnetic-field-induced self-assembly. ► It is a new way to make micro arrays simply, and the structures can be retained as the resins curve. ► The structure of arrays can be changed by adjusting the strengths of magnetic field. ► The self-assembled films have low reflectance in the range of 300-2500 nm.