Stabilizing Pickering Emulsions with Polymer Brush-Modified Tricompartmental Anisotropic Particles: A Simulation and Experimental Study.

We study the stability of oil-in-water Pickering emulsions using tricompartmental brush-modified anisotropic particles (TBPs) through Dissipative Particle Dynamics (DPD) simulations. Our study examines how TBP functionality, including brush length, density, and surface modification, influences emulsion stability. We designed four distinct tricompartmental macroparticles (TPs), labeled TP-1 to TP-4, by grafting polymer brushes via surface-initiated atom transfer radical polymerization (ATRP). In TP-1 and TP-4, initiators are embedded at the central 1/3 region and on 1/3 of one side of the outer spherical surface. In TP-2 and TP-3, initiators are placed on 1/3 of both surface sides and 2/3 of the surface. We examined the kinetics of brush growth, demonstrating the linear growth of polymer brushes consistent with first-order reaction kinetics of radical polymerization. In addition, we present experimental validation of surface modification and brush growth kinetics. This combined approach offers a detailed macroscopic analysis of emulsion formation and stabilization. We show that TBP-1 results in the highest emulsion stability, followed by TBP-3 and TBP-4, whereas TBP-2 has the least stability when polymer brushes have higher local densities. Increased brush density significantly enhances emulsion stability by improving interfacial wetting. However, at lower to moderate brush densities, the stability ranking shifts to TBP-3 > TBP-4 > TBP-2 > TBP-1 for the same brush length, aligning with experimental observations. These findings highlight the effectiveness of brush-modified TPs in stabilizing Pickering emulsions and provide valuable insights for designing functional particles tailored for emulsion-based applications.