Exploring chemical and structural features to tailor wetting properties of PVDF and PVDF/PMMA surfaces

Superhydrophobicity has proven to be a useful tool to meet the needs of the new circular economy, even though its large-scale development continues to be challenging mainly due to the low affordability of micro and nanometric roughness generation methods. In this work, non-stick polymer materials based on Poly(vinylidene Fluoride), PVDF, and its blends with Poly(methyl methacrylate), PMMA, were developed by a simple, fast and industrially accessible solvent-induced method aligned with the ecodesign philosophy. The chemical and structural features that determine the wetting behavior are evaluated in 18 different surfaces, that present varied surface energy (blend composition from 100 to 60:40 PVDF:PMMA) and topography (controlled by the method conditions). Wetting behavior was analyzed by measuring the water contact angles and its hysteresis, whereas the roughness parameters were determined by optical profilometry. By tuning the blend composition and the solvent-induced process conditions, it was possible to obtain either superhydrophobic surfaces with contact angles higher than 160° and hysteresis lower than 5° or parahydrophobic surfaces with high contact angles and high water adhesion. The fundamental features of both wetting behaviors were critically discussed. In addition, a proof of concept of the industrial viability of the method on a fragment of a commercial piece made of PVDF was successfully carried out.