Fabrication of a Waterborne Durable Superhydrophobic Material Functioning in Air and under Oil

A fundamental challenge in artificially structured/ chemically modified superhydrophobic surfaces is their poor chemical, mechanical, and structural robustness toward different mechanical abrasions. This limits their application potential in different fields of science and technology. Herein, a waterborne superhydrophobic material composed of clay particles is developed through a one-pot chemical modification in ambient conditions, forming durable micro-nano dual-structured coatings over a range of substrates, without adhesive. This chemical modification inverts the inherent hydrophilic nature of clay particles and provides an excellent superhydrophobic surface having a water contact angle >170 degrees (+/- 2 degrees) and contact angle hysteresis <5 degrees (+/- 2 degrees). The coating shows excellent durability against various induced damages and works efficiently both in air and within oils. The observed property is due to the controlled surface energy obtained by the incorporated chemical functionalities and enhanced surface roughness facilitated by the hydrophobic effect during slow evaporation of water from the coating material. Being a stable water dispersion, it enables large area coatings, thereby minimizing safety and environmental concerns. Use of this material to develop rugged waterproof-paper for paper-based technologies is also demonstrated. As clay is commercially available and economical, it is believed, this scalable organic-solvent-free superhydrophobic material will have a positive impact on various industries.