Figure 4. Various HIPPEs and synthesis of porous materials.

(a) Various stable HIPPEs formed with various particles and depletants. Scale bar, 5 mm. (b,c) SEM micrographs of polymeric porous material. (b) Porous material produced by photo-crosslinking continuous phase and freeze-drying stable HIPPE that contained 0.54 vol% silica particles, 10 wt% PEG, and 10 wt% PEGDA. Scale bars, 100 μm (left), 20 μm (middle) and 5 μm (right). (c) Porous materials produced by the stable HIPPE that contains 0.3 vol% TiO₂ particles, 26.5 vol% acrylic acid, 3 wt% PEGDA, and 1.5 wt% PEG. SEM micrographs indicate that both 1 μm-silica and 21 nm-TiO₂ are well exposed at the surface of the internal phase. Scale bars, 100 μm (left), 20 μm (middle) and 500 nm (right).