Abstract:

Oil-water miscible foams have been widely used in daily cosmetics, chemical industry, petroleum industry, etc., but the current reports on oil-water miscible foams mostly focus on the influences of external factors such as surfactants, temperature, pH and salinity on the stability of oil-water miscible foams. The effects of oil type and oil content on the formation and stability of aqueous foams have not been systematically studied. In this work, foaming experiments were conducted by changing the oil type and oil-water volume ratio. The formation and stability mechanisms of aqueous foam influencing by oil were explored by analyzing the foam volume, the half-life of foam drainage, the decay rate of foam, the microscopic particle size of foam, the surface tension of oil phase and the oil-water interfacial tension. The results were as follows: with the increase of carbon chain length of oil, the foaming property of aqueous foam was decreased; the foam stability increased with the increase of surface tension of oil; the oil-water volume ratio had important influence on the formation and stability of aqueous foam. At low oil-water volume ratio, foam lamellas were arranged closely, forming bubbles of different size. Moreover, due to the mutual extrusion between the bubbles, the microstructure morphology was chaotic and irregular. With the increase of oil-water volume ratio, the foam particle size became smaller and more uniform, and the foam structure became denser, making the foam more stable.

Key words: oil-water miscible foam, oil type, oil content, formation, stability