Porous hydrogels templated from soy-protein-stabilized high internal phase emulsions

Porous hydrogels with controlled morphology were successfully prepared from polymerizing soy-protein-isolate (SPI)-stabilized high internal phase emulsions (HIPEs). The ability of SPI to act as a surfactant in an oil-in-water HIPE containing acrylic acid or acrylamide monomer was investigated. The void and window sizes in the polyHIPEs were tailored by adjusting SPI and/or monomer concentration. Ultrasonication treatment was applied to vary the physical properties of the SPI. Although this treatment weakens the emulsifying efficiency of SPI, the HIPEs were stable enough to create polyHIPEs with larger pores and windows than polyHIPEs from untreated counterparts. The formation of polyHIPEs with interconnected, open-cell morphologies indicated that SPI is not a typical Pickering emulsifier. The performance of the hydrogels to capture heavy metal (e.g. lead (II)) ions was also explored. The highly interconnected polyHIPE structure with large voids revealed an enhanced absorption behavior compared with non-porous hydrogels. Graphic abstract