Construction Of Responsive Emulsion And Its Application In The Preparation Of Functional Materials

Pickering emulsions stabilized with solid particles were widely used in cosmetics,medical diagnostics and oil transportation.The temporary stability of the emulsion needs to be regulated by external stimulation in daily life.To date,many physical and chemical methods have been used to regulate the stability of the emulsion.Due to the good selection of Pickering emulsifiers and the adjustable particle size of emulsion droplets,the responsive Pickering emulsion was a good template for the preparation of functional materials.In this paper,a surfactant molecule with redox switch was designed to prepare Pickering emulsion with both magnetic field and redox response.The stability mechanism of Pickering emulsion was studied.In addition,the Pickering emulsion was used as template to prepare the composite polystyrene microspheres with fluorescence,which realized the real-time detection of iodate ions.The specific research contents are as follows:（1）Fe₃O₄ nanoparticles were prepared by solvothermal method,the agglomeration was improved by coating Si O₂.Ferrocenazine molecule（Fc A）was synthesized,and the oxidized Fc A was used to adsorb on the surface of magnetic Fe₃O₄@Si O₂nanoparticles by electrostatic interaction for hydrophobic modification.The obtained modified nanoparticles could be used to stabilize Pickering emulsion.The effects of surfactant concentration,emulsifier concentration,oil-water ratio and rotational speed on Pickering emulsion were discussed.Moreover,the stability of the emulsion could be modulated by redox and applying magnetic field.（2）Si O₂ nanoparticles modified by Rhodamine B was chosen to prepare Pickering emulsion,which could be used to obtain composite microspheres.By changing the polymerization parameters,the better preparation conditions were obtained:the concentration of emulsifier was 0.5 wt%,the ratio of oil to water was 5:5,the polymerization temperature was 75℃and the polymerization time was 12 h.Moreover,the obtained composite microspheres showed strong fluorescence measured by fluorescence microscopy.After the microspheres were dispersed in the aqueous phase and stood for three months,no significant change could be observed,which proved the good stability of microspheres.（3）Novel emulsion prepared with negatively charged Fe₃O₄ nanoparticles and amphiphilic methyl orange molecule was used as template to prepare Paraffin microspheres.The influence of emulsion stability on paraffin microspheres was discussed.The results showed that when the concentration of methyl orange was 1.0×10^-6 mol/L,the concentration of Fe₃O₄ nanoparticles was 0.001 wt%,and the ratio of oil to water was 2:8,the paraffin microspheres with good morphology could be prepared.