Abstract In this article we made a systematic study of the electrokinetically driven flow through a long nanochannel patterned with charged hydrophobic patch embedded along the walls. The hydrophobic patch possess either similar or opposite charge to that of the hydrophilic portion of the channel wall. The hydrodynamic slip length is considered to be a function of the surface charge distributed along the patch. We consider the aqueous medium as binary symmetric electrolyte solution with constant property Newtonian fluid. We adopt a nonlinear model based on the Poisson-Nernst-Planck equations coupled with Navier–Stokes equations. The coupled set of governing equations are solved using a finite volume method. We use a higher order upwind based total variation diminishing (TVD) scheme to discretize the convective and electromigration terms (i.e., hyperbolic terms) and the central difference scheme is used to discretize the diffusion term. We have identified several interesting key features of the modulation of electroosmotic flow (EOF) through such a nanochannel. An enhancement or a reduction in average flow rate may be achieved depending on the polarity of the charges distributed along the hydrophobic or hydrophilic portion of the channel wall. We have also shown that the reversal in EOF may occur depending on the critical choice of the pertinent parameters. We have further studied the selectivity of mobile ions by regulating the charge properties of the channel walls.

中文翻译：

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疏水贴片对纳米通道电渗流和离子选择性调节的影响

摘要 在本文中，我们系统地研究了电动驱动流过长纳米通道的流动，该纳米通道带有沿壁嵌入的带电疏水贴片。疏水贴片具有与通道壁亲水部分相似或相反的电荷。流体动力滑移长度被认为是沿贴片分布的表面电荷的函数。我们将水介质视为具有恒定性质的牛顿流体的二元对称电解质溶液。我们采用基于 Poisson-Nernst-Planck 方程和 Navier-Stokes 方程的非线性模型。使用有限体积方法求解耦合的控制方程组。我们使用更高阶的基于逆风的总变差减少 (TVD) 方案来离散化对流和电迁移项（即，双曲线项），中心差分格式用于离散化扩散项。我们已经确定了通过这种纳米通道调节电渗流 (EOF) 的几个有趣的关键特征。取决于沿着通道壁的疏水或亲水部分分布的电荷的极性，可以实现平均流速的提高或降低。我们还表明，根据相关参数的关键选择，可能会发生 EOF 的逆转。我们通过调节通道壁的电荷特性进一步研究了移动离子的选择性。取决于沿着通道壁的疏水或亲水部分分布的电荷的极性，可以实现平均流速的提高或降低。我们还表明，根据相关参数的关键选择，可能会发生 EOF 的逆转。我们通过调节通道壁的电荷特性进一步研究了移动离子的选择性。取决于沿着通道壁的疏水或亲水部分分布的电荷的极性，可以实现平均流速的提高或降低。我们还表明，根据相关参数的关键选择，可能会发生 EOF 的逆转。我们通过调节通道壁的电荷特性进一步研究了移动离子的选择性。