Properties of Fatty Amine–Silica Nanoparticle Interfacial Layers at the Hexane–Water Interface

Abstract

The formation and properties of composite layers of silica nanoparticles and an oil-soluble (fatty) amine surfactant at the oil−water interface have been studied using interfacial tensiometry, rheology, and contact angle measurements to characterize the synergy between the particles and surfactant. The initially hydrophilic particles interact with the surfactant only at the water−hexane interface. Synergistic interactions are required for interface stabilization. A key result is that nanoparticle attachment is driven by surfactant adsorption at the liquid interface. Particles are efficiently bound to the interface once the adsorbed surfactant layer is close to saturation. Surfactant adsorption onto the particle surfaces optimizes the particle wettability and promotes particle aggregation into networks that enhance the viscoelasticity of the interface. The implications of these results for controlling the formation and kinetic stability of emulsions containing particles and surfactant are discussed.

Effects of starch nanoparticles on phase inversion of Pickering emulsions

“…The interfacial tension also decreases with an increase in the concentration of HSNP (0.1 and 1 % by weight in the aqueous phase). This observation is consistent with the reduction in interfacial tension of oil-water systems reported in the literature [21] upon the adsorption of nanoparticles at the droplet surface. To ascertain the influence of salt and biocide on the interfacial tension, the experiments were repeated with HSNP dispersed in ultra-pure water.…”

Direct Determination of the Distribution Coefficient of Tridecyl Dimethyl Phosphine Oxide between Water and Hexane

“…This problem was considered in various books, such as [1][2][3][4]; also, a number of studies were published in which both adsorption (equilibrium and kinetic) and rheological characteristics at the surfactant aqueous solution/alkane (oil) interface are analysed [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Temperature- and pH-Dependent Shattering: Insoluble Fatty Ammonium Phosphate Films at Water–Oil Interfaces

“…3,13 One method of avoiding layer-by-layer film fabrication is by dispersing two components in separate, immiscible phases, such that they interact only at the interface. 14,15 However, encapsulation and film-formation by this method has been explored using only a narrow range of materials. Given the potential range of applications of such systems, a cheap material 2 that creates temperature-responsive films with tunable interfacial rheological properties, and that is suitable for large-scale production, is therefore rather desirable.…”