Stabilization of Oil-in-Water Emulsions by Colloidal Particles Modified with Short Amphiphiles

Abstract

Emulsions stabilized through the adsorption of colloidal particles at the liquid-liquid interface have long been used and investigated in a number of different applications. The interfacial adsorption of particles can be induced by adjusting the particle wetting behavior in the liquid media. Here, we report a new approach to prepare stable oil-in-water emulsions by tailoring the wetting behavior of colloidal particles in water using short amphiphilic molecules. We illustrate the method using hydrophilic metal oxide particles initially dispersed in the aqueous phase. The wettability of such particles in water is reduced by an in situ surface hydrophobization that induces particle adsorption at oil-water interfaces. We evaluate the conditions required for particle adsorption at the liquid-liquid interface and discuss the effect of the emulsion initial composition on the final microstructure of oil-water mixtures containing high concentrations of alumina particles modified with short carboxylic acids. This new approach for emulsion preparation can be easily applied to a variety of other metal oxide particles.

Porous Ceramics

“…Contact angle can also be tailored by changing the particles' surface chemistry or adjusting the composition of the fluids. Metallic and ceramic particles can achieve any contact angle (0< θ < 180º) by reacting or adsorbing hydrophobic molecules on their surfaces [28,29]. The use of short amphiphiles to tailor particles' wettability is a general and versatile approach for the surface modification of a wide range of ceramic and metallic materials [20].…”

“…1 outlines common methods of preparing porous ceramics and their corresponding products' degrees of porosity. The fabrication methods of microporous ceramics currently available can be classified as replica techniques, methods that employ sacrificial templates and direct foaming [29]. Ceramics' microstructures and properties depend on their fabrication method.…”

Nanoparticle effects on the water-oil interfacial tension

“…However, there is a long ongoing debate on whether or not nanoparticles (NPs) adsorbed at an interface can reduce the interfacial tension. [1][2][3][4][5][6][7][8][9][10][11] Briefly,…”

Preparation of Si3N4 Foam Ceramics with Nest‐Like Cell Structure by Particle‐Stabilized Foams

“…As opposed to conventional surfactant molecules that adsorb and desorb on relatively short time scales, 17,18 the high stability of particlestabilized foams in the wet state is attributed to the irreversible adsorption of the partially hydrophobic particles at the air-water interface. [17][18][19][20] Although colloidal particles have been widely used for foam stabilization, 21,22 the study on Si 3 N 4 as colloidal particles for foam stabilization during direct foaming method has not been reported. In this article, the preparation of porous Si 3 N 4 ceramics by particle-stabilized foams is investigated, the stability of Si 3 N 4 particle-stabilized foams is studied, and the Si 3 N 4 foam ceramics with nest-like cell structure are obtained.…”