Surface Modification of Polycarbonate by Ultraviolet Radiation and Ozone

Abstract

The effect of ultraviolet (UV) radiation in the presence of ozone as a surface treatment for polycarbonate is examined in regards to changes in the wettability, adhesion, and surface mechanical properties. Standalone, 175-mm-thick films of a commercially available polycarbonate were exposed to UV radiation from sources of different power with various treatment times in the presence of supplemental ozone. Significant decreases in the water contact angle were observed after exposure to UV radiation in the presence of ozone. After several variations in the experimental setup, it was determined that the change in water contact angle is a function of the UV irradiance and the work of adhesion follows a master curve versus UV irradiance. Nanoindentation experiments revealed that the modulus of the top 500 nm of the surface is increased following UV exposure, attributable to surface cross-linking. Adhesion tests to the surface (conducted by a pneumatic adhesion tensile test instrument) showed little change as a function of UV exposure. Analysis of adhesion test failure surfaces with X-ray Photoelectron Spectroscopy (XPS) showed the locus of bond failure lay within the bulk polycarbonate and the measured bond strength is limited by the bulk properties of the polycarbonate and=or the creation of a weak boundary layer within the polymer.

Rupture of Thin Liquid Films Induced by Impinging Air-Jets

“…Transparent plates of polycarbonate (PC, Sabic Lexan 9030, thickness 1 mm) were cleaned by sonication in isopropanol and chemically patterned by UV/ozone treatment 78 for 120 s (Jelight) using a shadow mask. The pattern consisted of a partially wetting, circular center area (diameter 17.5 mm) surrounded by a wetting perimeter, which prevents the film from dewetting from the edge of the substrate.…”

Evaluation of a Range of Surface Modifications for the Enhancement of Lateral Flow Assays on Cyclic Polyolefin Micropillar Devices

“…Many kinds of surface modification methods aimed at surface wettability enhancement have been described in the literature, including UV/ozone treatment,17–19 flame and corona discharge,20, 21 attachment of polymer particles by grafting or plasma polymerisation22–24 and many others. However, none of these techniques are without problems.…”

UV Surface Treatment of Polycarbonate for Ad-hesion Improvement to Liquid Silicone Rubber (LSR)

“…In studies by Bhurke et al, the effects of the increase of the surface energy of polycarbonate after UVC irradiation was examined regarding to the improvement of the adhesive strength compared to an epoxy adhesive. They did not identify any significant increase in adhesion [18].…”