(167s) Engineered Surfactants for Improved Sustainability of High Internal Phase Emulsion Polymer Foams

High internal phase emulsion polymer foams (pHIPE) are an easily made and simply tailorable adsorbent platform that takes advantage of either water-in-monomer or oil-in-monomer emulsions to create hydrophobic or hydrophilic polymer foams, respectively. While much of the work that has focused on pHIPE has studied the impact of monomer chemistry in order to facilitate new functionality and new applications, little has been done to improve the pHIPE through surfactant engineering. In making the initial high internal phase emulsion, a stabilizer is necessary in order to produce internal phase droplets within the continuous phase. Decades of work has demonstrated that engineering the structure of the surfactant, rather than relying on a single surfactant for all work, is an effective way of producing emulsions, coatings, particles, and foams with desired specific surface area or particle/droplet size. Despite this, little work has been done in the space of pHIPE that focuses on novel, engineered surfactants. This may be due to the fact that after polymerization (as the monomer of the HIPE becomes a polymer and encapsulates the internal phase), the surfactant is no longer thermodynamically driven to remain at the interface and must be washed off in order to not create an ecological burden. As such, this work focuses not only on the engineering of the surfactant structure as a stabilizing agent, but also enabling new surfactant chemistry that links the surfactant to the continuous polymer. In doing so, we have found that we can not only create pHIPE with superior porous properties, but also with a reduced manufacturing, chemical, and ecological burden.