Mathematical Modeling of Induced-Charge Electrokinetics

感应电荷电动学的数学模型

• 批准号: 0707641
• 负责人: Martin Bazant
• 金额: $ 28.77万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0707641&HistoricalAwards=false
• 关键词: Mathematical; Modeling; Induced; Charge; Electrokinetics

Bazant0707641 The investigator develops timely new mathematical models fornonlinear "induced-charge" electrokinetic phenomena, whereelectro-osmotic flows or particle motions are driven by electricfields acting on induced double-layer charge at polarizable(metal or dielectric) surfaces. The investigator and hiscolleagues have worked for five years on a unified theory of sucheffects, as well as related experimental studies in microfluidicsand colloids. In spite of a number of successes in predictingnew types of flows, however, the existing theory fails to predictsome crucial features of the experiments, such as flow reversalat high voltage and flow suppression at high concentration. Thetheory is based on the classical Poisson-Nernst-Planck equations,which are strictly valid only for "small" voltages ( 25 mV), butexperiments typically involve much larger voltages ( 1 V), whichcondense counterions near the surface and violate the dilutesolution approximation. The investigator builds a mathematicaltheory for this regime by modeling steric and correlation effectsdue to ion crowding, nonlinear permittivity and viscosity of thesolvent, and Faradaic reactions. The theory is tested againstexperiments and applied to design new microfluidic devices. This work has fundamental relevance for nanotechnology andbiotechnology. Induced-charge electro-osmosis (ICEO) is arecently identified nano-scale phenomenon with many applicationsin microfluidics and colloids. Because ICEO can be exploited tomanipulate fluids and particles with battery voltages, it couldenable revolutionary new portable or implantable biomedicaldevices, such as tiny drug infusion pumps and diagnosticlabs-on-a-chip. The mathematical work of the investigator seeksto advance our understanding of ICEO flows, especially inbiological liquids, by exploring consequences of molecularcrowding on the dynamics of electrolytes near highly chargedsurfaces.

Bazant0707641 研究者及时开发了新的非线性“感应电荷”电动现象的数学模型，其中电渗流或粒子运动是由电场作用于可极化（金属或电介质）表面的感应双层电荷驱动的。 研究者和他的同事们已经花了五年的时间来研究这种效应的统一理论，以及微流体和胶体的相关实验研究。 尽管在预测新型流动方面取得了一些成功，然而，现有的理论未能预测实验的一些关键特征，例如高电压下的流动反转和高浓度下的流动抑制。 该理论基于经典的Poisson-Nernst-Planck方程，该方程仅对“小”电压（25 mV）严格有效，但实验通常涉及更大的电压（1 V），这会使表面附近的抗衡离子凝聚，违反稀溶液近似。 研究者通过模拟离子拥挤、溶剂的非线性介电常数和粘度以及法拉第反应的空间效应和相关效应，建立了这一机制的理论模型。 该理论进行了测试againstexperiments和应用于设计新的微流体装置。 这项工作与纳米技术和生物技术具有根本相关性。 诱导电荷电渗（ICEO）是近年来发现的一种纳米尺度的现象，在微流体和胶体中有着广泛的应用。 由于ICEO可以利用电池电压来操纵流体和颗粒，因此它可能成为革命性的新型便携式或植入式生物医学设备，例如微型药物输液泵和诊断芯片实验室。 研究人员的数学工作旨在通过探索分子拥挤对高电荷表面附近电解质动力学的影响，促进我们对ICEO流动，特别是生物液体的理解。