Micro/nano-suction cup structure of silicone rubber fabricated by ArF excimer laser

Micro/nano-suction cups of silicone rubber, cylindrical swelling structures in micron size with a hole of hundreds nanometer diameter each, were fabricated by 193-nm ArF excimer laser-induced photodissociation of silicone rubber. To be periodically, silica glass microspheres of 2.5 μm diameter were aligned on silicone rubber via Al thin film during laser irradiation. The Al thin film underneath each microsphere was locally laser-ablated to enable a circular irradiation of subsequent laser pulses, then the exposed silicone rubber was photochemically swelled by the photodissociation of Si–O bonds of silicone rubber. Also, debris of aluminum surrounding the laser-ablated areas resulted in pushing microsphere up to adjust a focal point to the surface of silicone rubber to form a hole centered at each the swelled silicone. The fabricated structure showed clear superhydrophobic properties. Dependence of single pulse fluence of ArF excimer laser on the fabrication of micro/nano-suction cup structure was discussed, together with the variation of thickness of Al thin film from 10 to 100 nm. The use of the superhydrophobic silicone rubber we fabricated is expected as a kind of delivery system, toward holding a small object even in water by each micro/nano-suction cup structure.