Highly Robust, Pressure-Resistant Superhydrophobic Coatings from Monolayer Assemblies of Chained Nanoparticles

Despite significant progresses in development of superhydrohpobic coatings, their ability to resist small water droplets, which can exert large Laplace pressure on surface, remain limited. Here, a new strategy by self-assembly of a monolayer of chained silica nanoparticles, forming an ultrathin film (<100 nm) with two-tiered nanoasperity is presented. The resulting coating shows ultrahigh water repellency and high visible transparency. It can also repel low surface energy liquids, such as alcohol/water mixtures (surface tension >= 42 mN m(-1)). Importantly, the superhydrophobic coating demonstrates high resistance to impact pressure (at least 250 Pa) from water droplets dropped from 3.3 m height and internal Laplace pressure of 15 kPa from evaporated water droplets. Furthermore, the CNP coating remains to be superhydrophobic with condensed water droplets radius as small as 0.3 mm even after condensation for 6 h. In comparison, all of these properties are not possible from the assembly of spherical nanoparticles.

Automated summary

This study presents a new strategy by self-assembly of chained silica nanoparticles to form an ultrathin film with two-tiered nanoasperity, showing ultrahigh water repellency and high visible transparency. The resulting coating is able to resist impact pressure and internal Laplace pressure, demonstrating high durability.