Abstract
One method of modifying nanoparticle surfaces for foam stabilization is in situ surface modification with surfactants. Different surfactants have unique functional groups, which can have different effects on changing the surface wettability of nanoparticles. This paper analyzes the adsorption behavior of anionic, nonionic, and amphoteric surfactants on silica nanoparticles to investigate their effectiveness in modifying the wettability of the nanoparticle surface and increasing foam stability. Foam stability experiments were conducted at macroscopic and microscopic scales, along with zeta potential measurements, to examine the mechanisms of foam stabilization by silica nanoparticle combinations. Laboratory observations showed that the type of surfactant significantly affects the surface wettability of silica nanoparticles and consequently foam stability. At a constant concentration of 3 times the critical micelle concentration, the optimal wettability of silica nanoparticles for foam stability was achieved at surfactant concentrations of 0.05 wt % for nonionic, 0.10 wt % for amphoteric, and 0.50 wt % for anionic. The anionic surfactant combined with silica nanoparticles substantially impacted foam stability by forming a particle network at the gas-liquid interface, creating smaller, more uniform bubbles than the other surfactants. Additionally, due to stable emulsification, silica nanoparticles improved foam stability in the presence of oil.