Al2O3 particles, which are in situ hydrophobized upon adsorption of short-chain amphiphilic molecules, on addition of different amounts of unmodified SiO2, can be used as wet foam stabilizers. We tailored the microstructure of particle stabilized wet foams, average bubble size, and bubble size distribution by changing the composition of the initial colloidal suspension. The effects in terms of the combined effects of the contact angle, surface tension, and SiO2 content of the initial suspensions, are directly affected by the amphiphile concentration. Wet foams featuring average bubble sizes between 30 and 300 μm and air contents between 50-90% and porosity between 60-80% were obtained by adjusting the propyl gallate concentration as well as amount of additive (SiO2) in the initial suspension.

Keywords: Al2O3, Wet foam stability, Bubble size, Additives, Porous ceramics.