Simple Spray Deposition of the Water-based Superhydrophobic Coatings with High Stability for Flexible Applications
Superhydrophobic coatings have aroused much attention for their wide potential applications. However, the practical applications of the present artiﬁcial superhydrophobic coatings are not only hindered by the environmentally hazardous components containing ﬂuorinated materials and pungent organic solvents, but also poor material stability. Herein, a robust water-repellent organic-inorganic composite coating based on an aqueous dispersion was developed using a non-fluorinated material system consisting of a waterborne silicone-acrylic copolymer (SAC) and silica sol. Uniquely, the as-prepared SAC containing acid functional groups was ionized in alkaline environment first, followed by the introduction of the silica precursor into the SAC to in situ generate silica sol. The above non-fluorinated material system favors the application of the simple spray technique for the superhydrophobic coating (157.7˚) deposition, which could be flexibly employed on various substrates. The resulting composite coating that owns the strong micro- and nano-scale roughness structures embedded in the layer matrix can withstand at least 200 cycle abrasion without losing the superhydrophobicity. Moreover, the composite coating also shows a significantly high resistance to acid/base, organic solvent, UV photodegradation (UVA light illumination for 96 h) and high-temperature heating (400˚ for 80 h). Furthermore, this environmentally-friendly coating can be easily applied in self-cleaning (in either air or oil environment) and oil/water separation fields.