Hierarchically porous materials from layer-by-layer photopolymerization of high internal phase emulsions

摘要

A combination of high internal phase emulsion (HIPE) templating and additive manufacturing technology (AMT) is applied for creating hierarchical porosity within an acrylate and acrylate/thiol-based polymer network. The photopolymerizable formulation is optimized to produce emulsions with a volume fraction of droplet phase greater than 80 vol%. Kinetic stability of the emulsions is sufficient enough to withstand in-mold curing or computer-controlled layer-by-layer stereolithography without phase separation. By including macroscale cellular cavities within the build file, a level of controlled porosity is created simultaneous to the formation of the porous microstructure of the polyHIPE. The hybrid HIPE-AMT technique thus provides hierarchically porous materials with mechanical properties tailored by the addition of thiol chain transfer agent. A combination of high internal phase emulsion (HIPE) templating and layer-by-layer photopolymerization within computer-guided manufacturing technology is applied for the preparation of hierarchically porous polymeric structures with four levels of porosity. Objects with predetermined macroscopical structure and internal polyHIPE architecture are formed, exhibiting pores from micro- to macroscopic in size.