Self-assembled and elastomeric arm decorated surfaces for high stress resistant super-repellent materials

Abstract

Superhydrophobic (SH) particles and coatings with high mechanical resistance get widespread attention due to their versatile performance in applications such as self-cleaning, moisture protection and so on. In this work, superhydrophobic particles with excellent repellency to highly viscous and low surface tension liquids are synthesized via a two-step method. The grafting of soft and elastomeric polydimethyl siloxane segments onto silica surfaces confers the capacity for the absorption/distribution of mechanical impacts to SH particles. Thus, these particles can withstand high mechanical impact (∼8000 kg cm⁻²) and maintain a water contact angle (WCA) of around 150°. When SH particle incorporated PVDF-co-HFP is coated on substrates, the coating exhibits water roll-off properties with a sliding angle of <6° and a WCA of >160°. This coating is tolerant to water hammer pressures of 1.33 MPa and sand impingement energies of 3.6 × 10⁻⁷ J per grain, and the coating restores SH properties under ambient conditions after these tests. Additionally, the surfaces damaged by impalement/impingement undergo self-reconstruction to hold their super-repellent nature. A fibrous and porous structure morphology is evident in field emission scanning electron microscope images which is attributed to the heat treatment and subsequent solvent evaporation process. Moreover, the coating displays super-repellency to different liquids and shows good adhesion on various substrates such as aluminium, polyimide, chloroprene rubber and stainless steel.