A how-to approach for estimation of surface/Stern potentials considering ionic size and polarization
A how-to approach for estimation of surface/Stern potentials considering ionic size and polarization
复制标题
考虑离子大小和极化的表面/斯特恩电势估计方法
作者：
Liu Xinmin;Hu Feinan;Ding Wuquan;Tian Rui;Li Rui;Li Hang
双电层中的静电势是一个重要的参数，它显著地影响大量的物理、化学和生物性质和过程。在本研究中，一个新的方法来估计表面电位和斯特恩电位考虑离子体积和极化。扩散层中的离子强极化增加其有效电荷并决定Stern电位，而Stern层中的离子体积强烈降低其有效电荷并决定表面电位。例如，K+的有效电荷由于极化而增加0.699（从1到1.699），而由于有限的尺寸而减少1.359（从1.699到0.240）。测得的表面电位约为Stern电位的7倍。体积和极化对表面/Stern电位的影响分别进行了定量分析，体积效应大于极化效应。通过实验验证了一种新的团聚体稳定性理论。本文的工作还表明，只有在DLVO理论中引入强极化才能描述胶体粒子之间的相互作用。
Electrostatic potential in the electric double layer is an important parameter that significantly affects a large number of physical, chemical and biological properties and processes. In the present study, a new approach for the estimation of surface potential and Stern potential considering ionic volume and polarization was developed. Ionic strong polarization in the diffuse layer increases its effective charge and determines the Stern potential, while ionic volume in the Stern layer strongly decreases its effective charge and determines the surface potential. For example, the effective charge of K+ is increased by 0.699 (from 1 to 1.699) resulting from polarization, while it is decreased by 1.359 (from 1.699 to 0.240) due to finite size. The determined surface potential is about 7 times as high as the Stern potential. The effects of volume and polarization on the surface/Stern potentials were quantified respectively, and the former was stronger than the latter. A new theory was verified by the experiments for aggregates stability. The present work also showed that only introduction of the strong polarization into the DLVO theory can describe the interactions of colloidal particles.