Molecular Dynamics of Ionic Transport and Electrokinetic Effects in Realistic Silica Channels

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• 作者：Christian D. Lorenz ; Paul S. Crozier ; Joshua A. Anderson ; Alex Travesset
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：July 10, 2008
• 年：2008
• 卷：112
• 期：27
• 页码：10222 - 10232
• 全文大小：613K
• 年卷期：v.112,no.27(July 10, 2008)
• ISSN：1932-7455

文摘

Silica is one of the most widely used inorganic materials in experiments and applications involving aqueous solutions of biomolecules, nanoparticles, etc. In this paper, we construct a detailed atomistic model of a silica interface that captures the essential experimentally known properties of a silica interface. We then perform all-atom molecular dynamics simulations of a silica nanochannel subjected to either an external pressure or an electric field and provide an atomistic description of ionic transport and both electro-osmotic flow and streaming currents for a solution of monovalent (0.4 M NaCl) as well as divalent (0.2 and 1.0 M CaCl ₂) salts. Our results allow a detailed investigation of ζ-potentials, Stern layer conductance, charge inversion, ionic mobilities, as well as continuum theories and Onsager relations. We conclude with a discussion on the implications of our results for silica nanopore experiments and micro- and nanofluidic devices.