Wetting hysteresis induces effective unidirectional water transport through a fluctuating nanochannel

Noriyoshi Arai, Eiji Yamamoto, Takahiro Koishi, Yoshinori Hirano, Kenji Yasuoka, Toshikazu Ebisuzaki

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We propose a water pump that actively transports water molecules through nanochannels. Spatially asymmetric noise fluctuations imposed on the channel radius cause unidirectional water flow without osmotic pressure, which can be attributed to hysteresis in the cyclic transition between the wetting/drying states. We show that the water transport depends on fluctuations, such as white, Brownian, and pink noises. Because of the high-frequency components in white noise, fast switching of open and closed states inhibits channel wetting. Conversely, pink and Brownian noises generate high-pass filtered net flow. Brownian fluctuation leads to a faster water transport rate, whereas pink noise has a higher capability to overcome pressure differences in the opposite direction. A trade-off relationship exists between the resonant frequency of the fluctuation and the flow amplification. The proposed pump can be considered as an analogy for the reversed Carnot cycle, which is the upper limit of the energy conversion efficiency.

Original languageEnglish
Pages (from-to)652-661
Number of pages10
JournalNanoscale Horizons
Issue number5
Publication statusPublished - 2023 Feb 28

ASJC Scopus subject areas

  • General Materials Science


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