Microphase-Separated Macroporous Polymers from an Emulsion-Templated Reactive Triblock Copolymer

A polyHIPE (PH) is a macroporous polymer synthesized within a high internal phase emulsion (HIPE). The high-porosity, highly interconnected, open-cell structures and the PH-swelling-driven void expansion mechanism have made PH systems of interest for liquid absorption. Usually, only hydrophobic liquids or only hydrophilic liquids are considered for absorption applications. Here, PHs that are based solely on a reactive triblock copolymer (consisting of methacrylate-terminated poly(ethylene oxide) (PEO) end blocks and a poly(propylene oxide) midblock) were synthesized within oil-in-water HIPEs that are bereft of conventional monomers, cross-linking comonomers, and surfactants. The PH walls consisted of microphase-separated structures with crystalline PEO domains, a microstructure that is difficult to achieve in PHs. These PHs absorbed both hydrophobic liquids and hydrophilic liquids, with the PH-swelling-driven void expansion amplifying the absorption. For water absorption, the PH structure enhanced the temperature sensitivity (decreasing absorption with increasing temperature) and accelerated the response rate.