Abstract: Lauramidopropyl amine oxide (LAO) was synthesized.The isoelectric point of LAO,the effect of pH and temperature on adsorption behavior of LAO on the surface of the quartz sand and the effect of LAO on contact angle of the dodecane/water/glass were systematically investigated by using pH meter,high performance liquid chromatograph and surface tension meter respectively.Results showed that the isoelectric point of LAO is close to pH of 9;the increase of pH causes the critical micelle concentration of LAO to decrease;the increase of temperature and pH causes the adsorption of LAO on the surface of quartz sand to decrease;the contact angle of the dodecane/water/glass increases firstly,and then decreases to balance by increasing the mass concentration of LAO;the adsorption mechanism of LAO on the surface of quartz sand is double layer adsorption.

Key words: amphoteric surfactant, lauramidopropyl amine oxide, adsorption