Effectiveness of Emulsion-Templated Macroporous Polymer Micromixers Characterized by the Bourne Reaction

Abstract

High porosity, interconnected macroporous polymers prepared by the polymerization of high internal phase emulsions (polyHIPEs) stabilized by either surfactants or a combination of surfactants and hydrophobized silica particles were used as micromixers for liquids. The polyHIPEs had permeabilities between 30 and 2550 mD. The extent of micromixing was characterized by a system of two competitive parallel reactions (fourth Bourne reaction) carried out within the polyHIPEs. These competitive reactions, an acid−base neutralization and acid-catalyzed hydrolysis, proceed at very different rates such that the extent of the hydrolysis reaction is dependent on the extent of micromixing in the system, with lower hydrolysis yields indicating more effective micromixing. It was found that the hydrolysis yields were up to 50% lower in macroporous polymers compared to those in an empty tube and also up to 45% lower than those in a conventional spiral static mixer at a flow rate of 1 mL/min. Macroporous polymers with smaller pore throat sizes were found to give lower hydrolysis yields, corresponding to better micromixing; however, they did so at the expense of decreased permeabilities. However, using macroporous polymers results in a significant pressure drop across the flow cells, whereas an empty tube and conventional spiral static mixer cause a negligible pressure drop.

Emulsion Templating: Porous Polymers and Beyond

“…PH membranes were evaluated as separators in lithium-ion batteries and performed similarly to commercial polyolefin-based separators while exhibiting advantageous thermal and dimensional stabilities . The effectiveness of PHs as micromixers was evaluated by using two parallel reactions and demonstrated that the degree of micromixing increased with the reduction in the size of the interconnecting holes …”

“…139 The effectiveness of PHs as micromixers was evaluated by using two parallel reactions and demonstrated that the degree of micromixing increased with the reduction in the size of the interconnecting holes. 290…”

Dendritic Macrosurfactant Assembly for Physical Functionalization of HIPE-Templated Polymers

“…Ye et al [5] and Liu et al [6] obtained gold (or platinum) nanoparticle-mediated polyHIPEs with an open-cellular structure (which is critical to accessing catalytic sites). The free PEI macrosurfactants in the system possibly played a critical role, because when minor small surfactants are present in a Pickering emulsion system, open-cellular rather than closed-cellular polyHIPE is obtained [50][51][52][53][54][55].…”

Recent advances in separation applications of polymerized high internal phase emulsions

“…Compared with the conventional surfactants, solid particle stabilizers could obviously tailor the morphology of polyHIPEs [4–9, 44, 45], and a small amount of surfactant added to the Pickering HIPEs was beneficial to prepare macroporous polyHIPEs with a well‐defined open‐cell structure [14]. In addition, emulsion‐templated macroporous polymers could be transformed from a closed cellular structure to open cellular by increasing the emulsification energy for normal [46] and inverse [47] systems when the internal phase was less than 74% of the whole volume.…”