Flash NanoPrecipitation of Ionomers for the Scalable Production of Pickering Emulsifiers

Pickering emulsifiers have been demonstrated as advantageous alternatives to traditional surfactants, owing to their high interfacial adsorption energy and mechanical functionality. However, translating these benefits on an industrial scale requires continuous fabrication processes with high yield. One potential solution is flash nanoprecipitation (FNP), a scalable process for the production of polymeric colloids.

In this work, the FNP of homopolymers with ionomers is presented as a route for enhanced electrostatic stabilization and tunable expression of charge groups on particles for producing Pickering emulsifiers. Anionic groups on adsorbed ionomer chains promote electrostatic repulsion between aggregating nuclei during FNP, allowing control over resultant particle size while yielding 10-fold increases in particle mass output. Utilizing the tunable anionic surface charge afforded by ionomer content, the interaction between colloids and hydrophobic cations is studied. As salt concentration is increased, size stability is found to trend non-monotonically, a phenomenon related to polymer-specific changes in surface potential. Lastly, the surface activity of various colloid-salt combinations is demonstrated via the formation of stable Pickering emulsions.