Divergent effect of electric fields on the mechanical property of water- filled carbon nanotubes with an application as a nanoscale trigger

HF Ye and YG Zheng and LL Zhou and JF Zhao and HW Zhang and Z Chen, NANOTECHNOLOGY, 29, 025707 (2018).

DOI: 10.1088/1361-6528/aa98ee

Polar water molecules exhibit extraordinary phenomena under nanoscale confinement. Through the application of an electric field, a water- filled carbon nanotube (CNT) that has been successfully fabricated in the laboratory is expected to have distinct responses to the external electricity. Here, we examine the effect of electric field direction on the mechanical property of water-filled CNTs. It is observed that a longitudinal electric field enhances, but the transverse electric field reduces the elastic modulus and critical buckling stress of water-filled CNTs. The divergent effect of the electric field is attributed to the competition between the axial and circumferential pressures induced by polar water molecules. Furthermore, it is notable that the transverse electric field could result in an internal pressure with elliptical distribution, which is an effective and convenient approach to apply nonuniform pressure on nanochannels. Based on pre-strained water-filled CNTs, we designed a nanoscale trigger with an evident and rapid height change initiated by switching the direction of the electric field. The reported finding provides a foundation for an electricity-controlled property of nanochannels filled with polar molecules and provides an insight into the design of nanoscale functional devices.

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