writer：Ran Niu, Patrick Kreissl, Aidan T. Brown, Georg Rempfer, Denis Botin, Christian Holm, Thomas Palberg
keywords：pumping, low salt concentration
source：期刊
specific source：Soft Matter
Issue time：2017年
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 mm s-1 over hundreds of mm. 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 threedimensional (3D) flow when it is not. Using theory and numerical calculations we demonstrate that our observations are consistent with electroosmotic pumping driven by mmol L-1 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.
