Liquid Repellent Amorphous Carbon Nanoparticle Networks

This chapter aims to present an overview of the use of amorphous carbon nanoparticle films, generally referred to as carbonaceous films, towards liquid repellent technologies. The most common way of producing these films is by impinging a diffusion flame onto a target surface that collects the "soot" particles. Carbon nanoparticles collected in this way are generally amorphous in nature and form a porous nano-textured network having the suitable roughness features for liquid repellency. In fact, such flame synthesized carbonaceous films display super-hydrophobicity due to the combination of hydrophobic chemistry of the carbon particles and the sub-micrometer surface texture. However, they display very poor adhesion to the surface they are deposited on and hence cannot be used as liquid repellent surfaces except for the possibility of using their morphology as a template. The number of publications on liquid repellent carbonaceous films is very small as compared to other reported liquid repellent structures made by carbon nanotubes, nanofibers or graphene, mostly due to the aforementioned substrate adhesion problem. However, recently there have been some advances towards rendering them more durable and robust by depositing them on various polymeric surfaces or other micro-textured substrates such that partial melting of the substrate during flame impingement enables good bonding between the substrate and carbon nanoparticles. This chapter will first introduce the recent works related to liquid repellent nano-structured carbon nanoparticle films and their applications and then will present the new concepts and recent works conducted in the authors' laboratories towards producing more robust liquid repellent carbonaceous films by direct flame impingement and deposition.