Laser Preparing Tunable Wrinkles on the Surface of PDMS with Assistance of Pre-strain Stress

Abstract Micro directional wrinkles are widely used to functionalize the surface inside micro chips. In this paper, a nano-second laser, with the assistance of pre-strain stress, was applied to prepare tunable wrinkles on the surface of PDMS (polydimethylsiloxane). Experiments were carried out to investigate the impact of the pre-strain stress and the laser fluence on the wrinkles, like the direction and the wavelength. It was noticed that wrinkles prepared in the process grown vertically to the direction of the pre-strain stress. The wrinkles wavelength increased from about 500 nm to 2.5 μm when the power shifted from 5W to 8W. And strengthening the pre-strain stress sharply reduced the wavelength at the beginning then the trend was slowed down and some cracks were observed. And the end, a model was proposed to tune the pattern of wrinkles by precisely control pre-strain stress and the laser power. With that, several pattern of wrinkles was prepared.