The Interfacial Property Of Surfactant

Due to the unique interfacial character,surfactant has widely applied to various fields of industry and agriculture.Interfacial character is one of most important characters of surfactant.To study the interfacial character of surfactant can provide theoretical support for its application , so this research has momentous current significance and theoretical significance.The main content in this paper is included in the following aspects:(1) Determined the surface tension of the aqueous solution of sodium oleate with drop volume method under different temperature,pH and salt concentration;we also determined the surface tension of sodium oleate-Tween80 mixed system,and then we preliminary studied the surface activity of sodium oleate and the synergism effect of Tween80 to sodium oleate.Based on the research,we provided theoretical basis for phosphorus ore floatation.(2) The influence of surfactant (AOT) upon interfacial tension of the water and cyclohexane was determined at 40℃by pendant-drop technique.The results show that with increasing AOT concentration,the interface tension between water and cyclohexane decreases,and reach the lowest interface tension.At the lowest interfacial tension, the addition of cosurfactant (n-butyl alcohol) causes the ultra-low interface tension between cyclohexane and water,showing that the alcohol will participate the formation of microemulsion stabilized by AOT.(3) The critical micelle concentration(CMC) of AOT under AOT and AOT-TX-100 mixture (mole ratio=8:1) was obtained by conductance measurement.Based on the critical micelle concentration,we calculated the thermodynamic parameters of AOT micelle formation under AOT-TX-100 compound (mole ratio=8:1)condition,discussed its thermodynamic property.(4) The influence of temperature and salt was studied on the phase behavior of the SDS-CTAB aqueous surfactant two-phase.The triangle phase diagram of this system was drawn.It was found that the SDS-CTAB aqueous surfactant two-phase can form under some proportion of certain district at different temperature;when the concentration of NaCl is increased,the aqueous two-phase regions is expanded;the salt kind and salt concentration has important influence on the forming time of aqueous two-phase system.