Comments on “Influence of temperature and hydroxyl concentration on incipient soot formation in premixed flames,” by M. M. Harris, G. B. King, and N. M. Laurendeau

Abstract

The carbon soot has generally negative connotation due to the adverse impact on the human health and ambient environment. Most of the studies involving soot analysis focus on the need of preventing or reducing the sources of soot production. However, if the atmospheric soot aerosols are capable of repelling the ambient water vapor and thus impeding the water film formation on the soot particles’ outer shell, they can be considered as competitive and cost-effective candidates for the development of multifunctional non-wettable coatings. The physicochemistry of the soot, particularly the surface oxidation, the presence of heteroatoms and the degree of surface heterogeneity, regulates its chemical non-polarity and hygroscopicity. Appropriately selecting the types of soot sources facilitates the material’s recycling into a liquid-repellent tool with potential applicability in cryobiology, medicine, water purification devices, desalination systems, passive anti-bioadhesive and icephobic surfaces. This review article summarizes for the first time the main soot aerosol patterns based on their water uptake and provides detailed guidelines for the choice of suitable coating fabrication protocol and successive chemical processing. The latter are determinative factors in designing mechanically robust soot withstanding the impact of gusty winds, water jetting, abrasion or finger wiping. Finally, the state-of-the-art in the practical relevance of the hydrophobic soot is discussed, while the existing limitations and the future trends in the soot coatings technology are outlined.