Nanostructured polycarbonate for robust transparency and anti-fogging by control of self-masking metallic clusters

High-aspect-ratio nanostructures formed on a transparent polymer can be easily damaged after several cycles of anti-fogging testing, resulting in a reduction in optical transmittance. To ensure the robust wetting and optical properties of the transparent polycarbonate, we controlled the nanostructure geometries by adding the inert argon gas to oxygen gas during plasma-based selective ion etching process, resulting in both better transparency and longer-lasting anti-fogging properties. We confirmed that the size of the metallic clusters as a self-etching mask is strongly related to the aspect ratio of the final nanostructures. Since metallic clusters with relatively large diameters were formed with the addition of argon gas to oxygen gas, the robustness of the polycarbonate wettability and transparency instilled by the robust nanostructures was improved, as indicated by cyclic anti-fogging testing.