PolyHIPEs (PHs) are polymers with highly interconnected porous structures synthesized within high internal phase emulsions (HIPEs). Hydrogel polyHIPEs (HG-PHs), PHs that are usually templated within oil-in-water (o/w) HIPEs, can exhibit enhanced toughness, amplified and accelerated water uptake, and enhanced environmental sensitivity compared to conventional hydrogels synthesized from the same monomers. A HG-PH exhibiting broad-spectrum absorptions (water and various organic solvents) was recently synthesized based solely on a reactive triblock copolymer (TBC) (methacrylate-terminated poly(ethylene oxide) (PEO) endblocks and a poly(propylene oxide) midblock). The polymer walls consisted of microphase-separated structures with crystalline PEO domains, a microstructure that is difficult to achieve in PHs. These advantageous properties were then transferred to a conventional HG-PH based on acrylamide (AAm) by using the reactive TBC as a crosslinker. The TBC-crosslinked PAAm exhibited robust compressive behaviors with no chalkiness. On the other hand, the corresponding HG-PH that was crosslinked using a conventional low molecular weight crosslinker exhibited brittle behavior and was chalky. The combination of TBC crosslinking and emulsion-templating produced water uptakes that were accelerated, that were amplified (up to 161 g/g, almost 8 times that of the conventionally-crosslinked HG-PH), and that exhibited enhanced temperature sensitivity (decreasing by ~50% between 5 and 60 °C).

Toughening hydrogels through emulsion templating and triblock copolymer crosslinking

2019 Fall National Meeting

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