pH-Responsive Nanoemulsions Based on a Dynamic Covalent Surfactant

Developing solid-free nanoemulsions with pH responsiveness is desirable in enhanced oil recovery (EOR) applications. Here, we report the synthesis of an interfacial activity controllable surfactant (T-DBA) through dynamic imine bonding between taurine (T) and p-decyloxybenzaldehyde (DBA). Instead of macroemulsions, nanoemulsions can be prepared by using T-DBA as an emulsifier. The dynamic imine bond of T-DBA enables switching between the active and inactive states in response to pH. This switching of interfacial activity was used to gate the stability of nanoemulsions, thus enabling us to turn the nanoemulsions off and on. Using such dynamic imine bonds to govern nanoemulsion stability could enable intelligent control of many processes such as heavy oil recovery and interfacial reactions.