Chirality-dependent mechanical response of empty and water-filled single-wall carbon nanotubes at high pressure

• Published in: Carbon (New York) Vol. 95; pp. 442 - 451
• Main Authors: Torres-Dias, Abraao C., Cambré, Sofie, Wenseleers, Wim, Machon, Denis, San-Miguel, Alfonso
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2015; Elsevier
• Subjects: Carbon nanotubes; Chemical Sciences; Engineering Sciences; High pressure; Mechanical properties; Physics; Raman spectroscopy; Water filling; Carbon nanotubes; Mechanical properties; Water filling; Raman spectroscopy; High pressure
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2015.08.032

The mechanical stability of single-wall carbon nanotubes (SWCNTs) at high pressure was studied by high-resolution resonant Raman and wavelength-dependent fluorescence-excitation (PLE) spectroscopy resolving the vibrational and electronic resonances of 18 individual chiralities and furthermore even resolving the different behaviour of empty (closed, pristine) and water-filled (opened) SWCNTs (diameter range = 0.6–1.42 nm). We find that water-filling exerts a stabilizing counter-pressure on the SWCNT walls, leading to an increasing difference between the radial breathing mode frequencies of water-filled and empty SWCNTs at elevated pressures. For small diameter SWCNTs (d < 1 nm) with a chiral angle of ∼12°, in particular for the (7,2) chirality, an anomalous behaviour is observed, revealing an increased mechanical instability for these SWCNTs. We furthermore ascribe the longstanding contradiction between experiments and theory on the collapse pressure of SWCNTs to the presence of filling in most experiments to date, while empty SWCNTs follow the theoretically predicted collapse behaviour.