The Effect of Alkyl Chain Length in Quaternary Ammonium Cationic Surfactants on Their Foaming Properties

Abstract

Abstract In this study, foaming properties of four quaternary ammonium cationic surfactants dodecyltri-methylammonium chloride (1231), tetradecyltrimethylammonium chloride (1431), cetyltrimethylammonium chloride (1631), and octadecyltrimethylammonium chloride (1831) were investigated by the high stirring method. The microstructures of the surfactants were compared, and the effects of temperature, inorganic salts and methanol on the foaming activity of the cationic surfactants were studied. The results show that the lowest critical micelle concentration was gotten by 1831, which is 2.59 × 10–3 mmol L–1. The alkyl chain affects the Krafft point, and the longer the hydrocarbon chain is, the higher the Krafft point is. The foaming property of 1631 is the best, and the foaming volume of 1631 is 467 mL of which the half-life time can reach to 370.6 s. 1231 has the higher resistance to methanol and salinity. By investigating the microstructure of foam, the most stable foam is formed by 1631, and there is almost no polyhedron foam. All the results show that the alkyl chain of the quaternary ammonium cationic surfactants affects the foaming activity obviously, which may benefit the research and use of them in the related fields.