State Key Laboratory of Mechanics and Control of Mechanical Structures and Key Laboratory for Intelligent Nano Materials and Devices of MOE, Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Phys Rev Lett. 2023 Feb 24;130(8):084001. doi: 10.1103/PhysRevLett.130.084001.
Electro-osmotic flow is the motion of fluid driven by an applied electric field, for which an electric double layer near a charged surface is deemed essential. Here, we find that electro-osmotic flow can occur in electrically neutral nanochannels in the absence of definable electric double layers through extensive molecular dynamics simulations. An applied electric field is shown to cause an intrinsic channel selectivity between cations and anions, by reorienting the hydration shells of these confined ions. The ion selectivity then results in a net charge density in the channel that induces the unconventional electro-osmotic flow. The flow direction is amenable to manipulation by the field strength and the channel size, which will inform ongoing efforts to develop highly integrated nanofluidic systems capable of complex flow control.
电渗流是由外加电场驱动的流体运动，其需要在带电荷的表面附近存在双电层。在这里，我们通过广泛的分子动力学模拟发现，电渗流可以在没有可定义的双电层的情况下，在电中性的纳米通道中发生。施加的电场通过重新定向这些受限离子的水合壳，导致阳离子和阴离子之间存在固有通道选择性。离子选择性导致通道中产生净电荷密度，从而引起非常规的电渗流。流动方向可通过场强和通道尺寸进行控制，这将为正在进行的开发能够实现复杂流量控制的高度集成纳流控系统的努力提供信息。
