Poly(vinyl alcohol)-modified poly(methyl methacrylate) particles for solid-stabilized oil-in-water emulsions

In this study, submicron poly(methyl methacrylate) (PMMA) particles with surfaces modified using poly(vinyl alcohol) (PVA) (PMMA-PVA) were produced to formulate solid-stabilized emulsions including high internal phase emulsions with a dispersed phase of over 74%. The high-internal phase emulsions stabilized by PMMA–PVA exhibited gel-like behavior, and the oil droplets exhibited faceted shapes. PVA with a degree of saponification of 80 and 88 mol% was used as the surface modifier rather than PVA with > 96 mol%, assisting in the formation of a robust adsorbed layer on the PMMA particles. Coarse-grained molecular simulations revealed that the partially-hydrolyzed PVA exhibited a better adsorption behavior compared to the fully-hydrolyzed PVA, being thermodynamically adsorbed onto the PMMA surface in water owing to stable adsorption via its hydrophobic acetyl groups. Furthermore, PMMA–PVA reduced the interfacial tension as the degree of saponification of PVA decreased. Simulation and experimental results suggested that the acetyl groups of PVA not only adsorbed onto the PMMA surface but also promoted adsorption between PMMA and the oil–water interface. Overall, the findings of this study underscore the potency of PMMA–PVA as a particulate stabilizer for formulating O/W high internal phase emulsions.