Pickering emulsion stabilized by temperature-sensitive PS@PNIPA nanoparticles as microcontainers

Pickering emulsion has attracted the attention of many researchers because of its good stability. In some cases, such as catalyst separation and drug release, control of emulsion stability and demulsification under mild temperature is required. In this work, temperature-sensitive PS@PNIPA (polystyrene@polyisopropylacrylamide) with controlled PNIPA thickness was applied as the Pickering solid emulsifier. The effect of PNIPA thickness on the Pickering emulsion formation was studied by Polarizing optical microscope (POM). PS@PNIPA concentration was also found to be related to the size of the emulsion and the droplet size could be controlled from 17 μm to 39 μm. By changing the temperature, the emulsification/demulsification process of Pickering emulsion is reversible and repeatable for several cycles. Using ibuprofen as a chemical model, the maximum ibuprofen release rate reaches 93% and can be tuned by the temperature. Therefore, this opens up more potential applications for temperature-induced controlled demulsification for chemicals release and related fields. [Display omitted] •The size of Pickering emulsion increases with the increase of nanoparticle size and concentration.•Demulsification and re-emulsification can be achieved easily by changing the temperature around the LCST of PNIPA.•The chemical release rate of temperature-sensitive Pickering emulsion was 93%.