Superstable ultra-thin water film confined in a hydrophilized carbon nanotube

Yoko Tomo, Alexandros Askounis, Tatsuya Ikuta, Yasuyuki Takata, Khellil Sefiane, Koji Takahashi

Research output: Contribution to journalArticlepeer-review


Fluids confined in a nanoscale space behave differently than in the bulk due to strong interactions between fluid molecules and solid atoms. Here, we observed water confined inside “open” hydrophilized carbon nanotubes (CNT), with diameter of tens of nanometers, using transmission electron microscopy (TEM). A 1-7 nm water films adhering to most of the inner wall surface was observed and remained stable in the high vacuum (order of 10-5Pa) of the TEM. The super-stability of this film was attributed to a combination of curvature, nano- roughness and confinement resulting in a lower vapor pressure for water and hence inhibiting its vaporization. Occasional, suspended ultra-thin water film with thickness of 3-20 nm were found
and remained stable inside the CNT. This film thickness is one order of magnitude smaller than the critical film thickness (about 40 nm) reported by the DLVO theory and previous experimental investigations. The stability of the suspended ultra-thin water film is attributed to the additional molecular interactions due to the extended water meniscus, which balances the rest
of the disjoining pressures.
Original languageEnglish
Pages (from-to)1869-1874
JournalNano Letters
Issue number3
Publication statusPublished - 9 Feb 2018


  • Carbon nanotube
  • water
  • transmission electron microscopy
  • thin liquid film
  • disjoining pressure

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