Sustainable Repellent Coatings Based on Renewable Drying and Nondrying Oils

Contamination of surfaces can cause loss of performance in a variety of applications. Bioinspired coatings based on the lotus or pitcher plants provide surface topographies that create superhydrophobic or slippery features with self-cleaning properties. However, typical fabrication procedures often involve potentially toxic chemicals, perfluorinated compounds, nondegradable polymers, and energy-intensive methods, with negative consequences for the environment. Here, a sustainable coating process based on renewable materials to prepare superhydrophobic and liquid-infused coatings with minimal environmental impact is presented. A scalable spray coating protocol is used. Synthetic liquid and polymeric materials are substituted with natural drying oils, i.e., oils that react with ambient oxygen and cure to solid materials, as polymeric binder in which silica particles are partially embedded. The self-cleaning characteristics against aqueous contaminations are investigated as a function of the drying oil used as binder. The assessment of the mechanical stability reveals the advantage of an underlying primer layer of the pure oil. Furthermore, it is demonstrated that oils from renewable sources can act as lubricants for the creation of slippery surfaces. The efficiency of such sustainable slippery coatings in reducing concrete adhesion points toward their applicability in real world scenarios.

Automated summary

This study presents a sustainable coating process based on renewable materials to prepare surface coatings with superhydrophobic and liquid-infused properties. It uses natural drying oils as polymeric binder and silica particles for surface topographies that create self-cleaning and slippery features. The study demonstrates the potential of renewable oils as lubricants and their applicability in reducing adhesion in real-world scenarios.