Deep Eutectic Solvent-Driven Adaptive Interfacial Reconstruction for Noninterfacial-Responsive Emulsion Templates Enabling Thermally Triggered Polymer Release

Abstract Responsive surfactants have attracted considerable interest in controlled polymer release from water-in-oil polymer emulsions, as their stimuli-responsive behavior overcomes the dependence of conventional systems on hydrophilic surfactants. However, these systems often suffer from structural complexity, limited compatibility with functional monomers, and potential concerns regarding ecotoxicity and environmental persistence, which restrict their sustainability and broader application. To address these challenges, a green thermoresponsive deep eutectic solvent, oleic acid/lidocaine (OA-LD), was developed to construct a noninterfacial-responsive polymer emulsion template for stable synthesis and controlled release of polymers. Compared with conventional responsive surfactants, OA-LD possesses a simpler composition, facile preparation, favorable biodegradability, and low volatility, endowing the system with both responsive regulation capability and environmental compatibility. Molecular dynamics simulations were employed to elucidate the rapid demulsification mechanism. Upon thermal stimulation, OA-LD aggregates underwent directional migration toward the oil-water interface, disrupting the integrity of the surfactant film. Subsequently, OA-LD molecules embedded into the interfacial region and reduced the compactness of the interfacial film, thereby dynamically regulating emulsion stability and precisely controlling polymer release behavior. This strategy decouples responsive functionality from interfacial stabilization, providing a sustainable platform for intelligent polymer release technologies.