Wettability characteristics variation of nylon 6,6 by means of CO₂ laser generated surface patterns

CO₂ lasers can be seen to lend themselves to materials processing applications. These types of lasers have been used extensively in research and industry with the work carried out being well documented. This work investigated the surface modification of nylon 6,6 with a CO₂ laser in order to vary wettability characteristics. The wettability characteristics of the nylon 6,6 were modified by generating a number of patterns of various topography on the surface using the CO₂ laser. Thereafter the as-received and modified surfaces were analysed using white light interferometry to quantify the topographical changes. Any changes in the chemical composition of the surfaces were explored with EDX and XPS analysis. To quantify the wettability characteristics as a function of laser irradiation, contact angles where determined using a sessile drop device for each sample. In this way it was possible to determine the efficacy of the CO₂ laser generated topographical patterns in terms of wettability characteristics modification. It has been proposed that the increase in contact angle for the laser irradiated samples is due to a change in wetting regime from Wenzel to Cassie-Baxter.