| 초록 |
The streaming potential is generated by the electrokinetic flow effect within the electric double layer of charged surface. Charge properties are commonly quantified in terms of the zeta potential obtained with the Helmholtz-Smoluchowski (H-S) equation following measurement of streaming potential. Although the importance of electrokinetic characterization of membrane pore is well recognized, much attention has not been contributed on the fact that the practically interesting membranes have an asymmetric pore structure. In this respect, the zeta potential estimated by the classic H-S equation results in a deviated value. In order to obtain a rigorous zeta potential for asymmetric pores, an expression of correct streaming potential is derived by applying the framework of diffusion and convection with the Nernst-Planck equation for the Poisson-Boltzmann electric field. The present formula successfully provides the relative influences of each layer, pore length, pore radius, and Debye length, and then enables us to interpret the contribution of both skin and support layers. Relevant experimental results are also presented to implement our correct streaming potential. |
