Fabrication of large volume, macroscopically defined and responsive engineered emulsions using a homogeneous pH-trigger

Hydrolysis of glucono-δ-lactone (GδL) lowers the pH homogeneously throughout an aqueous solution. We exploit this non-invasive pH-trigger to prepare significant volumes of kinetically trapped, functional and responsive emulsion droplet assemblies—engineered emulsions—from highly stable polymer-functionalized emulsion droplets. In contrast to conventional acidification strategies, such as the addition of concentrated acid solutions, this approach also allows the kinetics of engineered emulsion formation to be monitored by rheometry thus providing valuable insight into the formation process. Engineered emulsions with enhanced morphological and compositional complexity can be prepared using GδL while maintaining reversibility—that is, the assembled droplets can be rapidly disassembled into free-flowing emulsion dispersions without compromising the droplet integrity. These developments may facilitate the broad exploitation of this generic new encapsulation and reversible assembly technology.