Nanofluidics in a carbon nanotube nanomechanical resonator

In this seminar, I will present our latest experimental developments in the direction of combining mechanical resonator and nanofluidic channel with a carbon nanotube.

First, I will discuss SU8 microfluidics. I will show that microfluidic channels fabricated in SU8 photoresist are suitable to operate in water and in vacuum, thus allowing to combine both antagonist world of fluidics (operating at ambiant pressure and with water) and mechanics (operating in secondary vacuum). Such channels can sustain relatively large water pressure up to 5 bars, and do not significantly degrade over several month. The porosity of SU8, measured by its ionic conductivity, is equal or better to PDMS, the standard in microfluidics [Pashayev2022].

Then, I will move to nanotube mass sensors. We found that carbon nanotube nanomechanical resonators exhibit exquisite mass sensitivity at room temperature down to zeptogram levels (1 zg = 10^-21 g), an order of magnitude better than the state of the art [Lassagne2008]. This feature is observed in several devices, making it a reliable asset. I will discuss the limitations to the mass sensitivity in terms of thermomechanical noise, frequency fluctuations, gaz damping, etc. [Basset2023].

Thanks to electrical breakdown, water can enter the nanotube channel. Our preliminary results indicate that carbon nanotubes field effect transistors can be used to distinguish water adsorbed on the surface of the nanotube from water confined inside the nanotube. Again, this feature is reproducible in several devices and independent of the metallicity of the nanotube [Pashayev2022].

Finally, I will detail how the mechanical resonator will be useful to answer, experimentally, open questions in the nanofluidic community about the structure of water, the phase diagram or the mechanism behind the fast flow observed in carbon nanotube.

Bibliography

[Pashayev2022] S. Pashayev, R. Lhermerout, C. Roblin, E. Alibert, J. Barbat, R. Desgarceaux, E. Chauveau, S. Tahïr, V. Jourdain, R. Jabbarov, F. Henn and A. Noury, in preparation (2022).
[Lassagne2008] B. Lassagne, D. Garcia-Sanchez, A. Aguasca and A. Bachtold, NanoLetters 8, 11 (2008).
[Basset2023] C. Basset*, H.-N. Tran*, R. Desgarceaux, R. Lhermerout, S. Pashayev, B. Lecarlate-Fernandez, C. Roblin, R. Jelinek, S. Tahïr, V. Jourdain, R. Jabbarov, F. Henn and A. Noury, in preparation (2023).
[Pashayev2022] S. Pashayev, R. Desgarceaux, R. Lhermerout, C. Roblin, R. Jelinek, S. Tahïr, V. Jourdain, R. Jabbarov, F. Henn and A. Noury, MRS Fall Meeting (2022).