A Universal Strategy for Microcapsule Diversity via Interfacial Surfactant Complexation in Fluorocarbon Oil-Based Triple Emulsions

Microfluidic emulsion-templating offers the preparation of functional microcapsules with tunable compositions and structures that are otherwise inaccessible using conventional methods. However, the inherent nature of emulsions relying on the immiscibility of phases comprising the emulsion limits the use of a single platform for the realization of microcapsules with diversity in shell materials. Herein, fluorocarbon oil-based triple emulsions are utilized as templates to achieve microcapsule diversity through a single platform. By introducing fluorocarbon oil with omniphobicity as the interstitial phase between the core and the shell phase, additional degrees of freedom are provided in the library of shell materials applicable in the design of functional microcapsules. Moreover, it is demonstrated that surfactant complexation at the emulsion interface effectively enhances the stability of the emulsion. This grants the use of various solidification methods including polymerization, freezing, and even solvent removal without delicate control of spreading coefficients or complex surfactant synthesis processes. The showcased microcapsule diversity signifies pivotal breakthroughs in microencapsulation technologies, illustrating how the synergistic use of fluorocarbon oil and interfacial complexation of surfactants in emulsions provides true freedom in universal microcapsule shell design for various applications including cosmetics, food, drug delivery, and cell therapy to name a few.