Surface Characterization of Laser Etched Poly(Vinylmethylsiloxane) Based Silicone Rubber Sheet

Abstract

This study discusses the etching of a poly(methylvinylsiloxane) (PVMS) silicone rubber sheet (VMQ) using a nanosecond-pulse laser operating at a wavelength of 355 nm under room temperature in air. We obtained a VMQ sheet with etchings of ~60 µm in depth and a surface roughness of 9.5 µm (S_a) through spread-dot patterns of focused laser irradiation. An increase in binding energy and composition of Si2p and O1s peaks, along with an increase in oxygen atom ratio, were observed using X-ray photoelectron spectroscopy (XPS) analysis. The surface oxidation of the etched VMQ sheet was similar to cases of laser irradiation on poly(dimethylsiloxane) based silicone rubber. The etched VMQ surface also showed high contact angle of 156° for water and 107° for propylene carbonate (PC), and both the angles were higher than those of untreated VMQ sheet. Moreover, ethanol showed greater wettability on the etched VMQ surface when compared with the untreated sample. Differences in liquid repellence between surfaces reflect the similarity of chemical structure of PVMS.