High strain sustaining, nitrile rubber based, large-area, superhydrophobic, nanostructured composite coatings

Elastomeric superhydrophobic nanostructured composite coatings scalable to large areas are prepared by spray casting particle-polymer dispersions. The dispersions consist of nanostructured carbon black particles along with submicrometer-sized poly(tetrafluoroethylene) particles dispersed in nitrile rubber solution in acetone, with the goal to attain superhydrophobicity with minimal content of particle fillers. The coatings are applied on various flexible substrates, which are subsequently stretched uniaxially. Upon drying, water droplet roll-off (sliding) angle measurements are performed to quantify the self-leaning ability of coated substrates being stretched uniaxially to 30% strain (coated silicone rubber) and 70% strain (coated polyester fabric). The coatings conform to the stretching of the substrates, while maintaining the self-cleaning property throughout this range. Self-cleaning is also maintained for cyclical stretching of coated substrates for strains 0-30% (coated silicone rubber) and 0-70% (coated polyester fabric) demonstrating the coatings' functional recovery. Droplet roll-off angles below 100 reveal good self-cleaning ability for these coatings. (C) 2011 Elsevier Ltd. All rights reserved.