Aligned Porous Beads Prepared by Frozen Polymerization of Emulsion-Templates Involving Tiny Emulsifier

High internal phase emulsion (HIPE) templated porous materials are attracting increasing interests due to its high porosity and tunable structure. However, large amounts (5-50 vol%) of suitable non-ionic surfactants are commonly required to stabilize conventional HIPE due to the high internal volume fraction of HIPE. In this work, applying frozen polymerization in HIPE, aligned porous beads were prepared with tiny surfactant (~0.1 wt%). These interconnected aligned porous beads were prepared through directional freezing, and frozen ultraviolet (UV) initiation of an oil-in-water (o/w) HIPE. The HIPEs are extruded by needle, and then directionally frozen in liquid nitrogen to form beads. The frozen beads were exposed under UV irradiation in a -20 °C ethanol bath to initiate the monomers in the aqueous phase. Moreover, the morphology of the resulting porous beads were tailored by vary the ratio of oil/water and the amount of emulsifier.