Superhydrophobic surfaces from sustainable colloidal systems

In recent decades, sustainable superhydrophobic surfaces from natural materials and sustainable processes have attracted increased interest due to their lower environmental footprint and potential applications in self-cleaning surfaces and biomedical devices. Although there is significant progress on selecting suitable nano and micro particles to prepare superhydrophobic surfaces, a comprehensive review on the direct use of sustainable colloidal particles (SCPs) is lacking. In this review, we highlight the recent advances on sustainable superhydrophobic surfaces using SCPs. The composition and properties, extraction methods, and chemical modifications are described, including cellulose nanocrystals, chitin/chitosan nanoparticles, and lignin nanoparticles. In addition to the physico-chemical properties and tunable dimensionality, the fabrication methodologies of superhydrophobic surfaces using modified colloids are described. Finally, the potential applications of these sustainable superhydrophobic surfaces ranging from oil/water separation, biomedical, water harvesting, biofabrication, microfluidic reactor, and food packaging are discussed together with a future perspective on the advances made.