Cellulose Acetate-Stabilized Pickering Emulsions: Preparation, Rheology, and Incorporation of Agricultural Active Ingredients

Abstract

We report the use of cellulose acetate (CA) nanoparticles (NPs) to produce oil in water Pickering emulsions. The CA NP can emulsify various oils and form stable emulsions at concentrations as low as 0.5 wt %. Rheological and microscopic analyses show evidence of interconnected NP aggregate networks between droplets. Yield stress measurements display evidence of "double" yielding. We postulate that the presence of the NP aggregates provides a secondary network between droplet clusters resulting in such behavior. We demonstrate the suitability of the emulsions as agriculture formulations by incorporating an agrochemical, abamectin (Abm), and a plant-growth-promoting microbe (PGPM) in the emulsions. Release assays exhibit sustained Abm release, promising higher efficacy at lower usage volumes. Incorporation of nonsporulating PGPM Pseudomonas simiae in the emulsions shows significantly higher microbe viability compared to controls after 70 days of storage. By demonstrating the application of CA NPs as a sustainable Pickering emulsifier, this study introduces the use of CA as a platform technology for the delivery of diverse agriculture cargos. A comprehensive evaluation of the system is articulated in a fundamental microstructure analysis and a demonstration of practical on-site attributes, including shelf-life stability and functional performance, verified through bioassays and plant growth studies.