Fluorine-free, robust and self-healing superhydrophobic cotton fabric based on the disulfide bond exchange reaction

Superhydrophobic (SH) surfaces are the surfaces with high static water contact angles (WCAs, > 150 degrees) and low sliding angles (SAs, < 10 degrees) which are prepared from hierarchical structures and low-surface-energy compounds. However, SH surfaces generally require a complex preparation procedure and exhibit poor durability. Coating treatment can potentially simplify the fabrication process and increase the surface durability. This work reports an SH surface fabricated from silica nanoparticles, 3-mercaptopropyltriethoxysilane, and a 4-6% (mercaptopropyl) methylsiloxane-dimethylsiloxane co-polymer by dip-coating and thermal curing processes. The coated fabric is highly durable and withstands repeated laundering, abrasion, and acid-base corrosion cycles. A disulfide bond exchange reaction that occurs under heat stress promotes the migration of coating segments and self-healing of SH property. As a result, the coating is able to endure 36 cycles of accelerated washing and maintain WCAs higher than 150 degrees. Furthermore, the coated fabric separates different oil-water mixtures with efficiencies greater than 99%, and its superhydrophobicity remain almost intact after multiple separation cycles. [GRAPHICS] .

Automated summary

This study reports a superhydrophobic surface fabricated from silica nanoparticles, 3-mercaptopropyltriethoxysilane, and a 4-6% (mercaptopropyl) methylsiloxane-dimethylsiloxane co-polymer by dip-coating and thermal curing processes. The coated fabric exhibits high durability and withstands repeated laundering, abrasion, and acid-base corrosion cycles. A disulfide bond exchange reaction promotes self-healing and allows the coating to maintain high static water contact angles after multiple washing cycles.