Plasma-induced formation of coatings on vegetable ivory microparticles immersed in silicone oil: Enhancing surface coverage using natural products

Aiming to enhance the potential applications of bioproducts, we developed an innovative approach for their hydrophobization using plasma activation of liquids. In this study, microparticles of vegetable ivory, a porous hygroscopic material, were treated by an air plasma jet while immersed in silicone oil. The in-liquid plasma treatment formed coatings that reduced particle water vapor sorption. Pore surface coverage and sorption reduction were enhanced by mixing silicone oil with copaiba oil-resin (Copaifera spp.). Mulateiro extract (Calycophyllum spruceanum) was not as effective, owing to a lower affinity with silicone oil. For the first time, we demonstrate the plasma-induced coating formation on particles immersed in liquid mixtures, a process in which liquid-liquid interfacial properties play a fundamental role.