2025 AIChE Annual Meeting

(385l) Conformation and Interfacial Activity of Anisotropic Patchy Nanoparticles at Oil-Water Interfaces: A Dissipative Particle Dynamics Study

Authors

Grant Kolacny, University of Texas at San Antonio
Masashige Shiga, University of Texas at San Antonio
Esteban Urena-Benavides, The University of Texas At San Antonio
Research Interests

Anisotropic particles with Janus-like surface chemistry are promising solid emulsifiers whose rational design requires a clear understanding of how their geometry and surface properties govern their assembly at fluid-fluid interfaces. Unlike traditional molecular surfactants where surfactants continually adsorb and desorb under equilibrium conditions, these solid colloids remain absorbed while simultaneously lowering interfacial tension and introducing strong kinetic barriers to coalescence, producing highly stable emulsions. Here, we perform extensive Dissipative Particle Dynamics simulations, where we vary the concentration, length and initial ordering of patchy nanorods, a model inspired by the amphiphilic nature of cellulose nanocrystals at the interface between immiscible liquids, to investigate their interfacial behavior. Interfacial tension was shown to be reduced with increasing interfacial particle concentration until full interfacial saturation, after which said reduction was governed by the interfacial organization of the particles. At higher concentrations a stacking between rods takes place, providing an extra layer to the barriers formed by already adsorbed particles. Results indicate that nanorod reorganization at the interface was inhibited by kinetic factors, preserving order in initially-ordered simulations with longer rods more effectively preserving this order. Overall, this study provides insight into energetic and kinetic factors that dictate Janus-particle organization in liquid systems.