Reactive amphiphilic hollow SiO₂ Janus nanoparticles for durable superhydrophobic coating

Durable superhydrophobic coating is attractive due to its long-term superhydrophobicity, anti-fouling and self-cleaning properties. However, the fabrication of durable superhydrophobic coatings on a fragile surface, including leather and paper, is still a challenge due to its bad resistance to harsh environments such as high temperature, high pressure and strong acid or strong base. Herein, we developed a universal way to fabricate long-lasting superhydrophobic coating on leather via amphiphilic Janus particles, which have one of the semispheres functionalized with hydrophobic 1-dodecanethiol and the other semisphere functionalized with hydrophilic β-mercaptoethylamine. Polyurethane with isocyanate end groups was sprayed on the leather surface as an intermediate layer to strongly link Janus particles with leather via cross-linking. Moreover, amphiphilic Janus particles were fabricated from hollow SiO₂ particles via a thiol-ene click reaction due to its low density. The superhydrophobic coating on leather possessed a high water contact angle of 162.2°. Furthermore, it still retained excellent hydrophobicity with a water contact angle of 154° after 140 cycles of abrasion using sandpaper. This study not only provides a novel method for the fabrication of amphiphilic hollow SiO₂ Janus nanoparticles, but also resolves the difficulties in constructing long-lived superhydrophobic coatings on fragile surfaces by existing methods. Meanwhile, the present study also suggests a potential way to translocate functional Janus microcapsules, which may give some significant suggestions on the future nanoparticle design for drug delivery and energy storage.