Ceramic foams shaped by oppositely charged dispersant and surfactant.

Wet foams fabricated by direct foaming for use as ceramic foams are usually fixed with extra additives. Here, we fabricated alumina ceramic foams involving only an anionic dispersant (ammonium polyacrylate, NHPA) and a cationic surfactant (dodecyltrimethylammonium chloride, DTAC) without extra additives. DTAC interacted with the NHPA adsorbed on alumina particles and changed the zeta potential and hydrophobicity of the particles. In wet foam, the partially hydrophobic particles not only acted as foam stabilizers, but also formed a 3D network, which fixed the wet foam. By optimizing NHPA and DTAC concentration, alumina ceramic foam with high porosity (79.8%), small average cell size (50 μm) and high compressive strength (30.3 MPa) was obtained. This facile method is promising to fabricate any other ceramic foam due to its universal nature. [ABSTRACT FROM AUTHOR]