Influence of nanoscale topography on the hydrophobicity of fluoro-based polymer thin films

In this report, the influence of surface features in the nanoscale range on the hydrophobicity of fluoro-based polymer thin films was studied. For this purpose, poly[4,5 difluoro 2,2-bis (trifluoromethyl)-(1,3 dioxole)-co-tetrafluoroethylene] was deposited by sol-gel spin coating technique on sputtered Cr–N interlayers with different surface structures. The wettability of the fluoro-based polymer thin film on the Cr–N interlayers was determined by dynamic contact angle measurements. It could be proved that structural changes in the nanometer range influences the contact angles and their hysteresis of low-surface energy materials. By applying fluoro-based polymer thin films on a nearly flat Si(1 0 0) wafer and a cone-like Cr–N structure with a certain roughness, the advancing contact angle for water on fluoro-based polymer thin film increased from 1208 to 1488 on the rough Cr–N interlayer.