Nanostructures and wetting properties controlled by reactive ion etching of fluorinated ethylene propylene

Abstract

We study the surface morphology, mass loss and wetting of fluorinated ethylene propylene surfaces which have been treated using reactive ion etching. We find that etching with argon gas alone results in a network structure, while oxygen combined with argon results in pyramidal hair-like structures, and by adding CF4 globules are found. We demonstrate that small alterations in the preparation allows one to create samples with either homogeneous nanostructures exhibiting large contact angles and very low hysteresis or more irregular structures which exhibits pinning sites that allow very large contact angle hysteresis. The advancing and receding contact angles are estimated based on the tilting plate method, and the pinning force measured for the samples is investigated for large droplets. The results reported here indicate that surface structure and contact angle hysteresis of fluorinated polymers can be manipulated for applications where either large or small contact angle hysteresis is needed.