Oil-in-Water Pickering Emulsion and Emulsion Polymerization Stabilized by Spherical Cellulose Particles Derived from Shola

Abstract

The widespread use of synthetic surfactants is recognized to have a significant environmental impact, and developing sustainable and environmentally benign substitutes is essential to mitigate the problems arising from their use in diverse applications. We introduce, herein, a novel spherical cellulosic particle derived from Shola, a cellulose-rich, abundant biomass, as an alternative surfactant material with equivalent or better properties. Shola is converted into spherical cellulosic particles (SCPs) of submicron size range using a simple one-step polyphosphoric acid treatment. These negatively charged particles show excellent dispersibility in water with long-term stability without the addition of any external agent. SCPs exhibit a remarkable affinity for hydrophobic dyes such as Nile red and curcumin, dispersing them efficiently in aqueous media. Further, SCPs stabilize oil–water interfaces, resulting in the formation of stable Pickering emulsions. Such emulsions exhibit shear thinning and thixotropic properties. SCP-stabilized Pickering emulsions containing polymerizable vinyl monomers can be polymerized in emulsion, providing uniform spherical polymer particles with high monomer conversion of about 90%. Importantly, unlike the toxicity associated with synthetic chemical surfactants, SCPs were found to be nontoxic when tested on hydroponic plants. They also underwent facile degradation under enzymatic conditions. Our experimental findings highlight the potential utility of Shola-derived spherical cellulosic particles as an efficient and sustainable alternative to synthetic surfactants.