Liquid repellent nanocomposites obtained from one-step water-based spray†
Significant research efforts have been directed towards the development of novel superhydrophobic and superoleophobic coatings. However, it is still highly challenging to develop facile and environmentally friendly methods that lead to surfaces and coatings with efficient liquid repellency. Herein, we demonstrate for the first time, a one-step water-based spray method on heated metallic substrates for the preparation of water and oil repellent polymer nanocomposite coatings by using hydrophilic silica nanoparticles. These environmentally-friendly coatings exhibit static contact angles exceeding 150° and roll off angles less than 5° for both water and oil and can also successfully repel a wide variety of other liquids. The influence of the chemical composition and the surface texture on the wetting properties are discussed based on measurements from white light interferometry, electron microscopy and X-ray photoelectron spectroscopy. When the substrates were treated with an adhesive primer, the wear abrasion resistance of the coatings was enhanced. The effect of silica nanoparticle dispersion in the coatings on wear abrasion is also investigated. Certain nanocomposites were found to exhibit good abrasion resistance by retaining their water repellency for up to 60 abrasion cycles under 20.5 kPa applied pressure.