Abstract
The effect of laser irradiation on surface wettability of cyclic olefin polymer (COP) was investigated. Under different laser parameters, a superhydrophilic or a superhydrophobic COP surface with a water contact angle (WCA) of almost 0° or 163°, respectively, could be achieved by direct femtosecond laser irradiation. The laser power deposition rate (PDR) was found to be a key factor on the wettability of the laser-treated COP surface. The surface roughness and surface chemistry of the laser-irradiated samples were characterized by surface profilometer and X-ray photoelectron spectroscopy, respectively; they were found to be responsible for the changes of the laser-induced surface wettability. The mechanisms involved in the laser surface wettability modification process were discussed.