Self-Stabilizing Encapsulation through Fast Interfacial Polymerization of Ethyl α-Cyanoacrylate: From Emulsions to Microcapsule Dispersions

Herein, fast interfacial polymerization (FIP) of highly reactive ethyl alpha-cyanoacrylate (ECA) monomers triggered by water-soluble initiators is demonstrated as a brand new method for instantly providing a strong steric barrier at the oil-water interface to effectively stabilize water-in-oil emulsions and microcapsule dispersions without the assistance of additive interface-active agents. Compared with emulsions stabilized by synthetic surfactants, amphiphilic polymers, and solid particles, such emulsions exhibit unique and attractive properties. Although polyECA polymers are hydrophilic, water-in-oil emulsions are anomalously produced through the FIP method. By regulating the polymerization rate, the interfacial coverage of irreversibly absorbing polymers can reach 100% within only 15 s, which is also considered to form a microcapsule dispersion. Besides, this emulsification method is readily applicable to prepare high-internal-phase-emulsion-like (HIPE-like) systems with an internal-phase volume fraction of 75.0% and generate stable monodispersed droplets via a microfluidic technique. The self-stabilizing encapsulation process through the FIP method presented in this work does open a new sight in the research field of both emulsions and microcapsules and may possess promising industrial applications in multiple areas.

Automated summary

The fast interfacial polymerization (FIP) method demonstrated in this study provides a strong steric barrier at the oil-water interface to stabilize water-in-oil emulsions and microcapsule dispersions effectively. This method can produce emulsions with unique properties and is applicable for preparing high-internal-phase emulsion-like systems and stable monodispersed droplets.