A universal fluorous technology toward superhydrophobic coatings.

HYPOTHESIS

Development of a process yielding large-sized non-wettable coatings of immediate applicative interest seems feasible by associating a membrane spining technique with the artificial mimic of a bio-inspired strategy toward water repellency. Accordingly, the question that arises is how to design a multiscale textured and chemically-activated continuous film.

EXPERIMENTS

A novel synergic combination of a processing technique and chemical treatment was developed in this purpose. Fluorinated nanocarbons were included in polyvinylpyrrolidone (PVP) microfibers via their addition in a precursor solution for electrospinning. The nanocomposites thus obtained were subsequently treated under gaseous molecular fluorine in mild conditions.

FINDINGS

Owing to the reactivity of PVP with F, both etching and functionalization occurred during such a post-treatment. The chemical modification undergone by PVP upon fluorination has been analyzed and a mechanistic approach proposed. An impressive dual texturing developed at the micro- and nanoscale thanks to the combined action of electrospinning, polymer etching and emergence of the nanofillers. This allowed a stable with time superhydrophobic coating-like film to be achieved.