Aqueous foam stabilized by plate-like particles in the presence of sodium butyrate

The addition of salt promotes the adsorption of layered double hydroxide (LDH) particles onto the air–water interface, but stable foams cannot be prepared from LDH dispersions at all the concentration of NaCl or sodium acetate. We generated stable foams using positively charged plate-like LDH particles in the presence of sodium butyrate. The effects of adding sodium butyrate to LDH on the particle zeta potential, adsorption behavior and the adsorption of modified particles at the air–water interface were studied. At a fixed LDH particle concentration, adding of a trace amount of sodium butyrate maximizes flocculation of the aqueous particle dispersion. Foams prepared under this condition of particle dispersion are most stable to coalescence and halt completely disproportionation. Also, the size of the bubbles is the smallest. The bubbles are stable when drying at 80 °C with little change in size. Laser-induced fluorescent confocal micrographs and scanning electron microscopy observations clearly confirm the adsorption of LDH particles on the foam surfaces, and the bubbles are armored by an interfacial particle multilayer.

SEM images of foams stabilized by butyrate anions-modified LDH particles at low and high sodium butyrate concentrations. The initial sodium butyrate concentrations are (a) 25 mM (b) 100 mM.Figure optionsDownload high-quality image (135 K)Download as PowerPoint slide