Synthesis and surface properties of amide-based amphoteric surfactants with different hydrophobic carbon chain length

A series of novel amphoteric surfactants containing amide groups with different hydrophobic carbon chain lengths were synthesized by using fatty amines with different carbon chain lengths, acrylamide and sodium chloroacetate as raw materials. The surface performance parameters and the thermodynamic functions of the surfactants in aqueous solution with different hydrophobic carbon chain length were determined and analyzed by the surface tension and conductivity. The surfactants were started to form pre-micellization before reaching the critical micelle concentration in the solution from the molar conductance-concentration squared curve and the apparent activation energy-concentration curve. According to the water separation time and the foaming performance experiments, as the hydrophobic carbon chain length grows, the emulsifying ability and defoaming property become better. The surfactants synthesized from octadecylamine belong to rapid-set emulsifier of asphalt.