Pingulkar Hrishikesh, Ayela Cédric, Salmon Jean-Baptiste
CNRS, Syensqo, LOF, UMR 5258, Université de Bordeaux, 178 Av. Schweitzer, 33600 Pessac, France.
IMS, CNRS, Bordeaux INP, UMR 5218, Université de Bordeaux, 33607 Pessac, France.
Lab Chip. 2024 Dec 3;24(24):5328-5337. doi: 10.1039/d4lc00831f.
Electrokinetic energy harvesting from evaporation-driven flows in porous materials has recently been the subject of numerous studies, particularly with the development of nanomaterials with high conversion efficiencies. The configuration in which the energy conversion element is located upstream of the element which passively drives the evaporative flow has rarely been studied. However, this configuration offers the possibility of increasing the harvested energy simply by increasing the evaporation surface area and/or the hydraulic resistance of the energy conversion element. In this work, we investigate this configuration with poly(dimethylsiloxane) (PDMS) chips playing the role of driving a pervaporation-induced flow through a polystyrene colloid plug in a submillimetre tube for the energy conversion. With an appropriate design of the venation of the PDMS leaves, we report the first experimental evidence of electrokinetic energy conversion from pervaporation-induced flows, which increases with the pervaporation area. We also provide new insights by demonstrating that this increase is limited by cavitation within the PDMS leaves, which occurs systematically as soon as the water pressure inside the leaf reaches ≃ 0 bar. Whatever the cavitation threshold, this phenomenon imposes an intrinsic limit on this configuration, underlining the need for innovative strategies to improve the harvesting of electrokinetic energy by evaporation.
从多孔材料中蒸发驱动流收集动电能量最近已成为众多研究的主题，特别是随着具有高转换效率的纳米材料的发展。能量转换元件位于被动驱动蒸发流的元件上游的配置很少被研究。然而，这种配置提供了通过简单地增加蒸发表面积和/或能量转换元件的水力阻力来增加收集能量的可能性。在这项工作中，我们使用聚二甲基硅氧烷（PDMS）芯片来研究这种配置，该芯片通过驱动全蒸发诱导的流动通过亚毫米管中的聚苯乙烯胶体塞来进行能量转换。通过对PDMS叶片脉络进行适当设计，我们报告了全蒸发诱导流进行动电能量转换的首个实验证据，该能量转换随全蒸发面积增加。我们还通过证明这种增加受到PDMS叶片内空化的限制提供了新的见解，一旦叶片内的水压达到≃0巴，空化就会系统性地发生。无论空化阈值如何，这种现象都对这种配置施加了内在限制，强调需要创新策略来改善通过蒸发收集动电能量的过程。
