Fabrication of two-dimensional close-packed monolayer polystyrene micro-spheres array master derived by spin-coating method for UV nanoimprint

In recent years, fabrication of two-dimensional (2D) and three-dimensional (3D) periodic structures from mono-dispersed colloidal spheres has attracted tremendous attention due to some fascinating applications including in sensors, 3D photonic band gap crystals, and 3D porous materials, etc.[1] Many methods have been developed to assemble the 2D polystyrene (PS) sphere arrays master, which includes vertical deposition, gravity sedimentation, dip-coating, dip-drawing, spin-coating, and so on.[2–4] As one knows, a high-quality 2D PS structure should be close-packed, monolayer and large-area. In this paper, the PS micro-spheres were successfully synthesized by an emulsifier-free emulsion polymerization technique and a 2D close-packed monolayer PS arrays master was also assembled by a spin-coating process. Influence of spinning speeds and the PS concentrations on the morphology of the PS micro-spheres array master was also discussed.