Fabrication and analysis of PMMA, ABS, PS, and PC superhydrophobic surfaces using the spray method

Abstract

In this study, superhydrophobic surfaces were fabricated using a facile spraying technique with poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS), polystyrene (PS) and polycarbonate (PC). Also, the surface energy was qualitatively analyzed via the water contact angle with respect to the spraying time and the sprayed position. Firstly, PMMA, ABS, PS and PC were dissolved by using solvents such as methyl chloride, methanol, THF (tetrahydrofuran), and methanol, respectively. After that, the dissolved polymer was sprayed onto a thin film of the same polymer for various spraying times. Nozzle size, pressure and spraying distance were fixed as 0.2 mm, 0.1 bar, and 100 mm, respectively, after several feasibility experiments. For the sprayed surfaces, the topology was analyzed with scanning electron microscopy (SEM) and confocal microscopy, and the surface energy was qualitatively analyzed using the water-contactangle measurement. According to a quantitative analysis using the roughness factor and he Wenzel equation, all specimens could be assumed to be in a Wenzel state. To convert the Wenzel state into a Cassie-Baxster state by decreasing the surface energy of polymer-sprayed specimen, we treated the polymer-sprayed surfaces by using trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane. Consequently, non-sticky superhydrophobic surfaces having water contact angles greater than 155° and water sliding angles lower than 8° were fabricated. The water contact angle and the water sliding angle were measured by using a contact-angle-measuring device. In addition, a brief qualitative analysis of the effect of surface topology on the water sliding angle was conducted for the polymer-sprayed specimens.