High Internal Phase Emulsions (HIPEs) are biphasic systems characterized by an internal phase volume fraction greater than 0.74. The introduction of a continuous polymerizable phase and subsequent removal of the internal phase results in cavities similar in size to the original droplets. The resulting porous polymer materials are called polyHIPEs. Recently, deep eutectic solvents (DES), have emerged as a non-aqueous alternative for the internal or external phase of nonaqueous HIPEs. DES are eutectic mixtures formed by the association of hydrogen bond donors (HBD) and ammonium or phosphonium salts as hydrogen bond acceptors (HBA). DES offer many of the benefits of ionic liquids without additional costs or complex preparation procedures. To date, polyHIPEs synthesized through a mass polymerization using nonaqueous DES as internal phase have resulted in monoliths whose shape is determined by the vessel in which the reaction takes place. However, there is technological interest in polyHIPEs beads due to its wide variety of applications derived from their versatility and higher surface area. A common strategy to obtain polyHIPEs beads is through a double emulsion process consisting of the dispersion of a HIPE into a surfactant solution to form droplets (water-in-oil-in-water emulsions) that are subsequently solidified by polymerization. This preparation method has been only reported by using aqueous media and there are no reports of the synthesis of these materials using nonaqueous DES. The current work presents for the first time the use of double emulsions formulated with DES with different viscosities to obtain polyHIPEs beads. DES used were choline chloride (ChCl) as HBA and either urea (U), glycerol (G) or ethylene glycol (EG) as HBD in a 2:1 molar ratio, with viscosities at 25°C of 750cp, 259cp, 37cp, respectively. Viscosity was a determining factor in the obtained bead shape.

Macroporous beads synthesized through double emulsions formulated with deep eutectic solvents

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.