Pumping fluid in ultranarrow (sub-2 nm) synthetic channels, analogous to protein channels, has widespread applications in nanofluidic devices, molecular separation, and related fields. In this work, molecular dynamics simulations were performed to study a symmetrical sinusoidal electric field-induced electroosmotic pump in ultranarrow charged carbon nanocone (CNC) channels. The results show that the CNC channels could rectify the ion current because of the different ion flow rates in the positive and negative half circles of the sinusoidal electric field. Electroosmotic flow (EOF) rectification yielded by the ion current rectification is also revealed, and net water flow from the base to the tip of the CNC channels is observed. The simulations also show that the preferential ion current conduction direction in the ultranarrow CNC channels (from base to tip) is opposite to that in conical nanochannels with tip diameters larger than 5 nm (from tip to base). However, the preferential EOF direction is the same as that of large conical nanochannels (from base to tip). We also investigated the influences of ion concentration and the amplitudes and periods of the sinusoidal electric field on the EOF pump. The results show that high ion concentration, large amplitudes, and long periods are desired for high EOF pumping efficiency. Finally, through comparison with a constant electric field and a pressure-induced water pump, we prove that the EOF pump under an alternating electric field has a higher pump efficiency. The approach outlined in this work provides a general scheme for pumping fluid in ultranarrow charged conical nanochannels.

中文翻译：

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超窄带电碳纳米锥中的交替电场感应离子电流整流和电渗泵†

在类似于蛋白质通道的超窄（2 nm以下）合成通道中泵送流体，已在纳米流体装置，分子分离和相关领域中得到了广泛的应用。在这项工作中，进行了分子动力学模拟，以研究超窄带电碳纳米锥（CNC）通道中的对称正弦电场感应电渗泵。结果表明，由于正弦电场的正半圆和负半圆中的离子流量不同，因此CNC通道可以整流离子电流。还揭示了由离子电流整流产生的电渗流（EOF）整流，并且观察到从底部到CNC通道尖端的净水流。仿真还表明，超窄CNC通道（从基端到尖端）中优先的离子电流传导方向与尖端直径大于5 nm的圆锥形纳米通道（从尖端到基端）相反。但是，优先EOF方向与大型圆锥形纳米通道（从基部到尖端）的方向相同。我们还研究了离子浓度以及正弦电场的幅度和周期对EOF泵的影响。结果表明，对于高EOF泵浦效率，需要高离子浓度，大振幅和长周期。最后，通过与恒定电场和压力感应水泵的比较，我们证明了在交变电场下的EOF泵具有更高的泵效率。