Agglomeration effect of nanoparticles on foam stability of nonionic surface-active liquid: experimental and density functional theory studies

Innovative applications of foam are the need of time which fundamentally depends on the stability of the foam. In the present research work, the static foam behavior of the nonionic surfactant Tween-20 in the presence and absence of Titanium dioxide nanoparticles (TiO2-NPs) was investigated. The role of TiO2-NPs on foaming power based on foam height and foamability was studied at different temperatures. At 29 +/- 1 C-0, maximum foam height for Tween 20 (5% surfactant solution in distilled water) without and with TiO2-NPs was increased from 45.60 to 60.30 cm exhibiting 32.25% increase. In view of studying foam stability, axial dye displacement rate (ADDR) test was performed without and with nanoparticles where TiO2-NPs resist liquid drainage. TiO2 -NPs and Tween-20 form intermolecular hydrogen bonding which helps to enhance the foam stability as revealed by the density functional theory (DFT) studies. However, TiO2 -NPs have tendency to agglomerate if zeta potential value is low that severely affect the foaming power and foamability.