Long pulse-repetition intervals of 100 to 500 ms of a 193 nm ArF excimer laser successfully increased the height of the photochemical micro-/nano-swelling of silicone rubber, observed with a scanning electron microscope. The effect of the interval was seen despite the heating of the silicone rubber to 80 °C during laser irradiation. The height of the micro-/nano-swelling was saturated when the laser pulse number was 300 or greater, although each of the saturated heights of the micro-/nano-swelling formed by several pulse-repetition intervals was different. Thus, a second ArF excimer laser irradiated the growing micro-/nano-swelling before the saturation; the saturated height of the growing micro-/nano-swelling could be controlled by the pulse-repetition interval of the second ArF excimer laser. To examine the process of micro-/nano-swelling, an early stage of the growth was observed using an atomic force microscope; a dent structure of the micro-/nano-swelling was clearly recognized. In addition, a needle-like structure of the micro-/nano-swelling could be formed when silica glass microspheres were sparsely aligned.
Photochemical Micro-/Nano-Swelling of Silicone Rubber Induced by Long Pulse-Repetition Interval of an ArF Excimer Laser