Method

The foaming method is based on using partially hydrophobized particles to stabilize wet foams. The adsorption energy of particles to a gas-liquid interface is orders of magnitude higher than that for surfactant molecules. As a result, particles can irreversibly adsorb to such interfaces, leading to a drastic improvement in foam stability compared to surfactants.

Initially hydrophilic particles are first dispersed in water (a) and subsequently surface modified upon adsorption of short amphiphilic molecules (b). This in-situ hydrophobization of initially hydrophilic particles enables the modification of high particle concentrations and their attachment to the gas-liquid interface to stabilize wet foams (c). Particles of various surface chemistry can be used as foam stabilizers by deliberately choosing the anchoring group of the adsorbing amphiphiles. The surface hydrophobization of a high concentration of particles and their adsorption to air-water interfaces enables the stabilization of high-volume wet foams that show neither bubble growth nor drainage over more than four days.