Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan.
Anal Chem. 2013 Aug 6;85(15):7527-34. doi: 10.1021/ac401536g. Epub 2013 Jul 8.
Fundamental understanding of ion transport phenomena in nanopores is crucial for designing the next-generation nanofluidic devices. Due to surface reactions of dissociable functional groups on the nanopore wall, the surface charge density highly depends upon the proton concentration on the nanopore wall, which in turn affects the electrokinetic transport of ions, fluid, and particles within the nanopore. Electrokinetic ion transport in a pH-regulated nanopore, taking into account both multiple ionic species and charge regulation on the nanopore wall, is theoretically investigated for the first time. The model is verified by the experimental data of nanopore conductance available in the literature. The results demonstrate that the spatial distribution of the surface charge density at the nanopore wall and the resulting ion transport phenomena, such as ion concentration polarization (ICP), ion selectivity, and conductance, are significantly affected by the background solution properties, such as the pH and salt concentration.
纳米孔中离子输运现象的基础理解对于设计下一代纳流控器件至关重要。由于纳米孔壁上可离解官能团的表面反应，表面电荷密度高度依赖于纳米孔壁上的质子浓度，而质子浓度又反过来影响纳米孔内离子、流体和颗粒的电动输运。本文首次从理论上研究了在 pH 调节的纳米孔中，同时考虑多种离子种类和纳米孔壁上的电荷调节的电动离子输运。该模型通过文献中可用的纳米孔电导实验数据进行了验证。结果表明，纳米孔壁上表面电荷密度的空间分布以及由此产生的离子输运现象，如离子浓差极化（ICP）、离子选择性和电导率，受背景溶液性质（如 pH 值和盐浓度）的显著影响。
