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根据DLVO理论,带电胶体颗粒相互作用是范德华引力和静电斥力共同作用的结果.Hamaker常数是表征范德华引力的一个关键参数,因此获得胶体的Hamaker常数是定量表征颗粒相互作用力的一个重要基础.本研究提出了基于动态光散射技术测定土壤胶体Hamaker常数的新方法.并以蒙脱石、紫色土和黄壤胶体为实验材料,成功实现了其Hamaker常数的测定.测定结果表明:蒙脱石胶体的Hamaker常数A_(eff)=6.5×10~(-20)J,紫色土胶体的Hamaker常数A_(eff)=7.5×10~(-20) J,黄壤胶体的Hamaker常数A_(eff)=5.3×10~(-19) J.虽然理论上用动态光散射技术测定胶体的Hamaker常数应该具有一定优势.但是,由于目前没有测定Hamaker常数的标准方法,本法的精读验证难以实现.所以,采用动态光散射技术测定物质Hamaker常数,其可靠性还需要更多的研究进行确认.
According to the theory of DLVO, the interaction of charged colloidal particles is the result of the interaction between van der Waals attractive force and electrostatic repulsion .Hamaker constant is a key parameter to characterize van der Waals attraction. Therefore, obtaining the Hamaker constant of colloids is an important basis for quantitative characterization of particle interaction. A new method to determine the Hamaker constant of soil colloids based on the dynamic light scattering (DLS) technique was proposed and the determination of the Hamaker constant was successfully carried out using the montmorillonite, purple soil and yellow soil colloids as experimental materials.The results show that the montmorillonite colloids The Hamaker constant A eff is 6.5 × 10 ~ (-20) J, the Hamaker constant of the purple soil is A eff = 7.5 × 10 ~ (-20) J, the Hamaker constant of the yellow soil colony is A eff = 5.3 × 10 ~ (-19) J. Although it is theoretically advantageous to determine the Hamaker constant of colloids by dynamic light scattering, there is no standard method for the determination of Hamaker constants. Therefore, Light scattering technique to determine the material Hamaker constant, the reliability still need more research to confirm.