Ultraporous gelatin foams (porosity >94%, ρ ≈ 0.039⁻0.056 g/cm³) have been fabricated via microwave radiation. The resulting foam structures are unique with regard to pore morphology (i.e., closed-cell) and exhibit 100% macroporosity (pore size 332 to 1700 μm), presence of an external skin, and densities similar to aerogels. Results indicate that the primary foaming mechanism is governed by the vaporization of water that is tightly bound in secondary structures (i.e., helices, β-turns, β-sheets) that are present in dehydrated gelatin films but not present in the foams after microwave radiation (700 Watts).
Keywords: foam; gelatin; microwave processing.