Surface Treatment of Polydimethylsiloxane (PDMS) with Atmospheric Pressure Rotating Plasma Jet. Modeling and Optimization of the Surface Treatment Conditions

Surface treatment of polydimethylsiloxane (PDMS) with a rotative nozzle atmospheric pressure plasma jet (APPJ) was reported. Operating conditions were optimized by statistical design of experiments, using water contact angle and XPS as response variables; OES (optical emission spectroscopy) was used for plasma diagnosis. The nozzle‐PDMS distance and the torch speed were the most influencing parameters and were optimum at 6.6 mm and 10.3 m s−1, respectively. The extent of hydrophobic recovery of treated PDMS, investigated by water contact angle measurements, was less than what reported in the literature for this amorphous polymer. However, the APPJ treatment proposed in this paper is meant to be inserted in line for a homogeneous surface treatment of PDMS for enhanced adhesion improvement to coatings or adhesives. Nozzle‐sample distance and torch speed are revealed as the most influencing factors of atmospheric pressure plasma jet (APPJ) for surface treatment and hydrophilicity enhancement of polydimethylsiloxane (PDMS). Degree of surface modification is correlated with homogeneity of APPJ treatment, plasma composition and temperature, and treatment conditions are optimized through maximizing oxygen content of plasma‐treated surface.