Institut für Physik, Johannes Gutenberg Universität Mainz, 55128 Mainz, Germany.
Institute for Computational Physics, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
Soft Matter. 2017 Feb 15;13(7):1505-1518. doi: 10.1039/c6sm02240e.
An ion-exchange-resin-based microfluidic pump is introduced that utilizes trace amounts of ions to generate fluid flows. We show experimentally that our pump operates in almost deionized water for periods exceeding 24 h and induces fluid flows of μm s over hundreds of μm. This flow displays a far-field, power-law decay which is characteristic of two-dimensional (2D) flow when the system is strongly confined and of three-dimensional (3D) flow when it is not. Using theory and numerical calculations we demonstrate that our observations are consistent with electroosmotic pumping driven by μmol L ion concentrations in the sample cell that serve as 'fuel' to the pump. Our study thus reveals that trace amounts of charge carriers can produce surprisingly strong fluid flows; an insight that should benefit the design of a new class of microfluidic pumps that operate at very low fuel concentrations.
介绍了一种基于离子交换树脂的微流泵，它利用微量离子产生流体流动。我们的实验表明，我们的泵在几乎去离子水中运行超过 24 小时，并在数百微米的距离上产生 μm s 的流体流动。当系统受到强烈限制时，这种流动呈现出远场、幂律衰减，这是二维（2D）流动的特征，而当系统不受限制时，则呈现出三维（3D）流动的特征。我们利用理论和数值计算证明，我们的观察结果与由样品池中 μmol L 离子浓度驱动的电渗流泵一致，这些离子浓度作为泵的“燃料”。因此，我们的研究表明，微量的电荷载体可以产生出人意料的强流体流动；这一见解应该有助于设计一类在非常低的燃料浓度下运行的新型微流泵。
