pH and Magnetism Dual-Responsive Pickering Emulsion Stabilized by Dynamic Covalent Fe3O4 Nanoparticles

Abstract

Herein, we describe pH and magnetism dual-responsive liquid paraffin-in-water Pickering emulsion stabilized by dynamic covalent Fe3O4 (DC-Fe3O4) nanoparticles. On one hand, the Pickerinfigureg emulsions are sensitive to pH variations, and efficient demulsification can be achieved by regulating the pH between 10 and 2 within 30 min. The dynamic imine bond in DC-Fe3O4 can be reversibly formed and decomposed, resulting in a pH-controlled amphiphilicity. The Pickering emulsion can be reversibly switched between stable and unstable states by pH at least three times. On the other hand, the magnetic Fe3O4 core of DC-Fe3O4 allowed rapid separation of the oil droplets from Pickering emulsions under an external magnetic field within 40 s, which was a good extraction system for purifying the aqueous solution contaminated by rhodamine B. The dual responsiveness enables Pickering emulsions to have better control of their stability and to be applied more broadly.

Application of Different Stimuli-Responsive Polymeric Micelles for Drug Release

“…Normally, magnetismresponsive polymeric micelles act under a double stimulus such as pH and magnetism dual-responsive. For example, Ren et al prepare a kind of dynamic covalent Fe3O4 nanoparticles which are dualresponsive by pH and magnetism in paraffin in water pickling emulsion [6]. This kind of polymeric micelles which contains a Fe3O4 core can separate the oily drugs from emulsions under the effect of an external magnetic field.…”

Recyclable Fe3O4 Nanoparticles Responsive to Temperature for Heavy Oil Viscosity Reduction: Synthesis, Characterization, and Performance

“…Solid particle-stabilized Pickering emulsions have attracted much attention due to their low toxicity and long-term stability . Nanoparticles are tiny particles, usually between 1 and 100 nm in size.…”

“…Therefore, viscosity reducers in response to various stimuli have attracted much attention at present. 17,18,35,36 Stimulus-responsive emulsions can be divided into physical and chemical stimuli. Physical stimuli generally include light, a magnetic field, and temperature, which do not directly invade the emulsion.…”

“…Solid particle-stabilized Pickering emulsions have attracted much attention due to their low toxicity and long-term stability. 17 Nanoparticles are tiny particles, usually between 1 and 100 nm in size. They have excellent capability of penetration and adsorption, adjustable physicochemical properties and unique thermal properties, and excellent chemical and physical stability under harsh reservoir conditions.…”

“…In oil transportation, emulsion polymerization, and other aspects, Pickering emulsions only need temporary stability, so they can quickly switch between stability and instability. Therefore, viscosity reducers in response to various stimuli have attracted much attention at present. ,,, Stimulus-responsive emulsions can be divided into physical and chemical stimuli. Physical stimuli generally include light, a magnetic field, and temperature, which do not directly invade the emulsion.…”