van der Heyden Frank H J, Stein Derek, Dekker Cees
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Phys Rev Lett. 2005 Sep 9;95(11):116104. doi: 10.1103/PhysRevLett.95.116104. Epub 2005 Sep 8.
We report measurements of the streaming current, an electrical current generated by a pressure-driven liquid flow, in individual rectangular silica nanochannels down to 70 nm in height. The streaming current is observed to be proportional to the pressure gradient and increases with the channel height. As a function of salt concentration, it is approximately constant below approximately 10 mM, whereas it strongly decreases at higher salt. Changing the sign of the surface charge is found to reverse the streaming current. The data are best modeled using a nonlinear Poisson-Boltzmann theory that includes the salt-dependent hydration state of the silica surface.
我们报告了对单个高度低至70纳米的矩形二氧化硅纳米通道中流动电流（一种由压力驱动的液体流动产生的电流）的测量结果。观察到流动电流与压力梯度成正比，并随通道高度增加。作为盐浓度的函数，在约10 mM以下它大致恒定，而在较高盐浓度时则急剧下降。发现改变表面电荷的符号会使流动电流反向。使用包含二氧化硅表面盐依赖水合状态的非线性泊松 - 玻尔兹曼理论对数据进行建模最为合适。
