Effect of hydrophobic modification of cellulose nanocrystal (CNC) and salt addition on Pickering emulsions undergoing phase-transition

The charge density of emulsifiers determines the thermodynamics and kinetics adsorption properties at the oil-water interface of an emulsion. This study examines the rupture resistance and stability of the crystallized dispersed phase based on the partitioning capability of cellulose nanocrystals (CNCs) with different surface charges. The charge density of CNC particles was designed through salt addition and hydrophobic modification. The measurement of dynamic interfacial tension confirmed that the reduction of negative charge of CNC particles improves their Pickering stabilizer role. We observed that the interfacial tension displayed a sigmoidal profile with increasing time. The dynamic stability of the emulsion during phase transition of the oil phase was enhanced by increasing the interfacial particle accumulation via the reduction of surface charge of CNC. The results indicated based on the surface charge adjustment, a balance between diffusion rate and kinetic barrier adsorption of particles is required to achieve optimum system stability.