  The interaction of amino acids (glycine, L-valine, L-isoleucine and
L-leucine) with alumina surface was studied to induce partial hydrophobization
and production of ultrastable particle-stabilised foams. The evaluation of
these amino acids was carried out by mechano-quantum simulations followed by
experimental tests (foamability, zeta potential, contact angle and foam
lifetime measurements). The experimental results agreed with the trends pointed
out by the simulations. The selected amino acids interact with alumina
particles in aqueous media and in a broader pH range, leading to
hydrophobization of surfaces, which was more intense for amino acids with
higher molecular mass (isoleucine and leucine). As a consequence, ultrastable
foams with a longer lifetime (> 100 hours) were produced and the foam
microstructure was preserved from ageing phenomena. Moreover, the attained
foams were stable at different pH, opening up new possibilities to develop
macroporous multiphasic ceramics, which can result in novel materials for
thermal insulation at high temperatures.
