Small molecules derived Tailored-Superhydrophobicity on fibrous and porous Substrates—with superior tolerance

Abstract In the past, different approaches were adopted to prepare superhydrophobic interfaces for demonstrating various prospective applications, where different polymers or nanomaterials are associated for achieving appropriate hierarchical topography and essential chemistry. The commonly used deposition solutions consisted of polymer or nanomaterials prepared in a specific solvent have poor shelf-life. Moreover, the unavailability of robust and optically transparent superhydrophobic coating following a scalable, rapid and single-step deposition process remained a bottleneck problem for its various prospective and relevant applications at real-world scenarios. Here, a catalyst-free 1,4-conjugate addition reaction between distinct and strategically selected small molecules allowed to prepare an active deposition solution with prolonged (200 days) shelf-life in various and commonly used reaction media. The small molecules derived deposition solution allowed a rapid and scalable synthesis of abrasion tolerant, optically transparent (99.2%) superhydrophobic coating on different relevant fibrous and porous substrates—following either dip-coating or spray coating process. Further, the appropriate choice of small molecules and the concentration of deposition solutions controlled adhesive interaction (from 24 μN to 204 μN) and hydrophobicity (from ∼ 134° to 160°) of the small molecule derived coatings. The entirely small molecules derived bio-inspired coating sustained various physical/chemical abrasive exposures including knife test, repetitive sandpaper abrasion, tensile deformation, adhesive tape peeling, washing, ironing, and prolonged (300 days) UV irradiation, sea water, river water etc. Such interfaces were successfully extended for different practically relevant applications including self-cleaning, oil/water separation, no-loss transfer and mixing of aqueous droplets etc. Moreover, the superior shelf-life of the deposition solution and liberty for selecting different reaction media makes this design exceedingly elegant for industrial scale-up in near future.