Multi-responsive polymer-stabilized magnetic engineered emulsions as liquid-based switchable magneto-responsive actuators

Abstract

Oleophilic magnetic nanoparticles can be encapsulated within stable surface functionalized oil-in-water emulsion droplets. Judicious control of the droplet surface functionality affords these disperse soft materials a unique transition between a free flowing and a gelled state. This transition is mediated by a simple pH switch. High level control over the gelation step is demonstrated as is a concomitant change in the magneto-response—from high magnetophoretic mobility to magneto-actuation. All processes show reversibility and modularity that allows the fabrication of complex, multi-component and site-isolated soft materials. These functional magnetic emulsions have potential bio-medical relevance as non-invasive, responsive in vivo delivery vehicles.