Emulsions and Emulsion Templating Enabled by Deep Eutectic Solvents: From Stable Biphasic Systems to Advanced Materials

Abstract

Deep eutectic solvents (DESs) have emerged as versatile liquid media whose tunable polarity, structural diversity, and dynamic molecular organization extend beyond their role as sustainable solvent alternatives. Concurrently, emulsion templating has become a strategy for fabricating macroporous materials with controlled architectures and functionalities. However, DES-enabled emulsions remain viewed as unconventional biphasic systems rather than functional platforms for materials design. In this Viewpoint, we discuss how DES physicochemical properties—including polarity, viscosity, dynamic hydrogen-bonding networks, ionic character, and selective solvation—redefine the dispersed or continuous phase in high internal phase emulsion (HIPE) templating. Rather than acting as passive templates, DESs direct interfacial assembly, transport, and material formation, enabling functional polyHIPEs and adaptive porous architectures with properties inaccessible through conventional emulsions. We identify scientific challenges involving interfacial organization, stabilization mechanisms, predictive formulation, and practical constraints and outline opportunities to establish DES-enabled emulsions as platforms for engineering tunable, sustainable, multifunctional, hierarchically structured materials.