Microbead patterning on porous films with ordered arrays of pores

Abstract

A method of patterning microbeads on polystyrene/silica films with ordered arrays of pores that were fabricated using a nonlithographic breath-figure method, is described. A solution of polystyrene/silica in toluene is dropped onto a clean solid substrate to cover the surface of the substrate. Breath figures form when the cold substrate, with the polystyrene/silica film on the surface, is brought in contact with moist air. The cold surface of the substrate leads to the nucleation and growth of the water droplets in the polystyrene/silica films. It was observed that the sizes of pores can be readily controlled by changing the polystyrene/silica ratio, the concentration of polystyrene/silica in toluene, and the amount of the solution added onto the surface of the substrate. It was also observed that the size of pores plays an important role in patterning the microbeads. This method has the potential to be used in bead-based multiplexed detection and sensing applications.