Rigorous testing to assess the self-cleaning properties of an ultra-water-repellent silicone rubber surface

• Published in: Surface & coatings technology 2019-09, Vol.374, p.557-568
• Main Authors: Maghsoudi, K., Momen, G., Jafari, R., Farzaneh, M.
• Format: Article
• Language: English
• Subjects: Air pockets; Carbon black; Cleaning; Contact angle; Contaminants; Contamination; Hydrophobicity; Kaolin; Outdoor condition; Properties (attributes); Self-cleaning; Silicon dioxide; Silicone rubber; Spraying; Suspended contamination; Ultra-water-repellent surface; Ultrasonic testing; Wenzel and Cassie-Baxter regimes
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2019.05.073

Ultra-water-repellent silicone-based surfaces were produced to study their self-cleaning properties. First, we investigated the consistency of the micro-nano air pockets that are present between the surface asperities responsible for the formation of the Cassie-Baxter regime. We then performed a comprehensive series of self-cleaning experiments involving both suspended and non-suspended contaminants using various materials (e.g., kaolin, carbon black, silica, etc.) and contaminant-applying methods (e.g., dropwise, spraying, wet or dry contaminants). In this paper, the self-cleaning tests were arranged from the less severe, i.e., non-suspended contamination tests, to more severe, i.e., wet suspended contamination test, and ending with the most severe, i.e., dry suspended contamination test. Due to the ultra-low contact angle hysteresis, the produced surfaces showed favorable self-cleaning properties against the various types of contaminants and the different means of contaminant application. The produced surfaces retained their water repellency properties following application of the contaminants and after the cleaning of the surfaces, thus verifying the self-cleaning performance and resistance of the fabricated superhydrophobic silicone surfaces. [Display omitted] •Ultra-water-repellent silicone-based surfaces were produced using an industry-applicable method.•The consistency of the micro/nano air pockets responsible for the formation of Cassie-Baxter regime was confirmed.•The self-cleaning properties were assessed through several methods for applying the contaminants and cleaning the surfaces.•The maintained ultra-low contact angle hysteresis ensures that the self-cleaning properties remained robust for all tests.