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Practical applications require scalable, low cost and facile approaches to fabricate coatings that are repellent to liquids and yet are resistant to mechanical impact and abrasion which may occur during service operation of these materials. Here we report fabrication of superhydrophobic (SHP) coatings on paper substrates by one-step spray-coating of fluorinated silica nanoparticles. The coatings were extremely repellent to water and organic liquids with surface tensions higher than ~ 45 mN/m, as demonstrated by the sliding angles that are lower than 5°. The coated paper substrates retained their liquid repellency behavior without any discernable change in their static contact and sliding angles following different mechanical wear tests. Mechanical robustness together with demonstrations in self-cleaning, anti-icing and food-packaging show great promise for the use of fabricated paper substrates in different applications. A significant finding of the present work is that the mechanical robustness of the spray-coated fluorinated silica nanoparticles in the absence of any polymeric matrix/binder was dramatically higher on paper in comparison to flat substrates. These results suggest that the inherent microstructure of the paper provides a suitable matrix for protecting the functionalized nanoparticles against external mechanical effects and present an effective strategy for improving the mechanical robustness of the coatings fabricated by one-step spray-coating of nanomaterials. [ABSTRACT FROM AUTHOR]

Solution-phase deposition of nanomaterials represents a highly promising technology with strong industrial application potential for the fabrication of superhydrophobic surfaces. An important barrier towards the adaptation of such materials and processes in a broad range of applications is the limited mechanical durability of the nanostructures. Herein, we present a universal solution to this challenge by benefiting from the unique micro-structure of paper. Our approach is based on transferring the structure of paper into a target material, to form a mechanical protection layer for nanomaterials that were deposited from solution-phase, i.e. spray-coating. We demonstrate this concept through the transfer of the structure of paper to a free-standing PDMS film using a simple molding process. Spraying a dispersion of alkyl-silane functionalized silica nanoparticles on the structured free-standing film results in a hierarchically structured superhydrophobic surface with a water contact angle of 175° ± 2° and a sliding angle <2° ± 1°. The fabricated superhydrophobic surface displays high levels of mechanical, chemical and thermal stability. The robust, inexpensive, scalable, flexible, and environmentally friendly nature of the presented approach may be a key enabler in superhydrophobic coating applications. Unlabelled Image • Transferring the structure of paper as a generalizable strategy for fabrication of robust superhydrophobic surfaces • All-solution processable, inexpensive, scalable, and environmentally friendly fabrication • Inherently flexible coatings adaptable to virtually all types of substrates [ABSTRACT FROM AUTHOR]