Effect of steam-treatment time on the length and structure of single-walled and double-walled carbon nanotubes

Abstract

A major challenge to turn the potential of carbon nanotubes (CNTs) into customer applications is to reduce or eliminate their toxicity. Taking into account health and safety concerns, intensified research efforts have been conducted to improve the biocompatibility of CNTs, including the development of new shortening and purification strategies. Ideally, the methods used for improving the biocompatibility of CNTs should not alter the electronic properties of CNTs. Herein, we report on the shortening of a sample containing single-walled and double-walled CNTs using steam and obtain new insights in the properties of the steam-treated CNTs. The present study shows that short CNTs (median length ca. 200 nm) can be obtained under the reported conditions. Raman analysis reveals that wider and outer nanotubes undergo more significant changes than the narrower and inner ones, especially after a prolonged steam treatment. ; The research leading to these results has received fundingfrom the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007–2013/under REA grant agreement n8 290023 (RADDEL). ICN2 ac-knowledgessupport from the Severo OchoaProgram(MINECO, Grant SEV-2013-0295), and M. Kalbacthe support from MSMTproject LL1301. M. Kierkowicz and E. Pach are enrolled in the PhD Program in Materials Science at UAB. ; Peer reviewed