Stabilization of Pickering Emulsions by Hairy Nanoparticles Bearing Polyanions

Abstract

Pickering emulsions are increasingly applied in drug delivery, oil–water separation, composite materials preparation, and other fields. However, systematic studies on the stabilization of Pickering emulsions to satisfy the growing application demands in multiple fields with long-term conservation are rare. Compared to conventional solid nanoparticles, polyanion-modified hairy nanoparticles are more stable in practical environments and are investigated in this study. Poly (sodium p-styrenesulfonate) was grafted to a polystyrene (PS) core via a photoemulsion polymerization. A hairy nanoparticle bearing polyanions called poly (sodium p-styrenesulfonate) brush (PS@PSS) was synthesized. The size and uniformity of the Pickering emulsions stabilized by PS@PSS were investigated via a polarizing microscope. The stability of Pickering emulsions were optimized by adjusting critical factors like ultrasonic power and time, standing time, oil phases, salt concentration, and water:oil ratio. Results indicated that the Pickering emulsions could be stabilized by PS@PSS nanoparticles, which showed remarkable and adjustable partial wetting properties. It was found that the optimized conditions were ultrasonic power of 150 W, ultrasonic time of 3 min, salt concentration of 0.1 mM, oil phase of hexadecane, and water:oil ratio of 1:1. The formation and stability of Pickering emulsion are closely related to the hairy poly (sodium p-styrenesulfonate) brush layer on the nanoparticle surface.

Graphene Oxide Pickering Emulsion – A Novel Reaction Medium for the Synthesis of 2‐Aminothiazole

“…The macroscopic physical properties of oil like density, viscosity surface tension etc. largely affect the interfacial tension and wetting of the particles which leads to affect an emulsion droplet size and volume fraction [53] . Here three different oil phases are tested viz.…”

Pickering Interfacial Catalysis—Knoevenagel Condensation in Magnesium Oxide-Stabilized Pickering Emulsion

“…As the surface tension of the oil phase increases, the droplet size of the emulsion formed decreases. 51 In the case of hexadecane, the shape of the emulsion droplet changes from spherical to elongated (Figure 12F), indicating that the curvature effect is more dominant for liquids with high viscosity. 52 The emulsion stability was also tested for some conventionally used organic solvents like toluene, xylene, cyclohexane, dichloromethane, and chloroform.…”

Effective Crude Oil Pickering Emulsification by Oil-Soluble Spherical Polymer Brushes

“…After being exposed to an external magnetic field, the latex particles could be efficiently separated from water and oil recovery could be achieved by elevating the temperature to dissemble the assembly. Recently, our group has conducted research on utilizing water-soluble spherical polymer brushes (SPBs) to stabilize model oil, that is, decane or hexadecane in water . After introducing water-soluble polystyrene (PS)-poly­(sodium p -styrenesulfonate) (PSS) brushes into oil/water mixtures, stable Pickering solutions with well-tuned performance could be prepared successfully.…”

“…Recently, our group has conducted research on utilizing water-soluble spherical polymer brushes (SPBs) to stabilize model oil, that is, decane or hexadecane in water. 17 After introducing watersoluble polystyrene (PS)-poly(sodium p-styrenesulfonate) (PSS) brushes into oil/water mixtures, stable Pickering solutions with well-tuned performance could be prepared successfully. However, in these cases, model oil including toluene and dodecane was used and the emulsification of crude oil in water still remains a challenge because of its high viscosity and complicated composition.…”