A combined experimental and computational study on the interfacial distribution behavior in colloidal particle-surfactant co-stabilized Pickering emulsions

Abstract

Recently, co-stabilized Pickering emulsion (CPE) that stabilized by colloidal particles and surfactant has received increased research attention, owing to its improved stability and fluid properties comparing with conventional emulsions stabilized by particles or surfactants alone. Herein, the dynamic distribution behavior at multi-scale and the synergistic-competitive interfacial absorption in CPE co-stabilized by Tween20 (Tw20) and zein particles (Zp) were studied by experiment combined simulation method. The experimental studies identified the delicate synergistic-competitive stabilization phenomenon tuned by the molar ratio of Zp and Tw20. Meanwhile, dissipative particle dynamic (DPD) simulation was utilized to reveal the distribution and kinetic motion. Based on the two- and three-dimensional simulation on the formation of CPE, simulation revealed that Zp - Tw20 aggregates were formed when anchoring at the interface. The interfacial adsorption efficiency of Zp was improved at low Tw 20 concentration (0-1.0%wt), Tw20 inhibited the Brownian motion of Zp at the interface and competed them out at high concentrations (1.5-2.0%wt). Zp was departured from the interface 4.5 Å to 10 Å, as Tw20 increased from 1.06% to 5%. The study offers a novel approach to reveal the dynamic distribution behavior of surface active substances during the dynamic formation process of CEP, which will expand our current strategies for interface engineering of emulsions.

Keywords: Co-stabilized Pickering emulsion; DPD simulation; Formation mechanism; Interfacial competition.