Effect of Steam‐Treatment Time on the Length and Structure of Single‐Walled and Double‐Walled Carbon Nanotubes

Abstract

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 are conducted to improve biocompatibility of CNTs, including the development of new shortening and purification strategies. Ideally, the methods used for improving the biocomapatibility of CNTs should not alter the electronic properties of CNTs. Here, we report on the shortening of a sample containing single-walled and double-walled CNTs using steam and get 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.

Comparative study of shortening and cutting strategies of single-walled and multi-walled carbon nanotubes assessed by scanning electron microscopy

“…The suggested combination of sulfuric/nitric acid followed by steam results in a 1. CNTs [32,37]. Therefore, silica or alumina together with iron (from the catalyst) will contribute to the inorganic solid residue remaining after TGA in air.…”

“…The CNTs were treated with water steam under argon atmosphere at 900 °C for the desired amount of time (1, 12 or 25 h) and subsequently refluxed with 6 M HCl overnight. The sample was vacuum filtered onto a polycarbonate (PC) membrane, rinsed with distilled water until the pH of the filtrate was neutral and dried in the oven at 100 °C [32,37].…”

Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging

“…Steam-opened and -shortened14 (ca. 400–450 nm) and purified15 single-walled CNTs (SWCNTs), which are widely regarded as biocompatible16, were first tested as containers for lead.…”

Evaluation of the immunological profile of antibody-functionalized metal-filled single-walled carbon nanocapsules for targeted radiotherapy

“…As-received Elicarb ® SWCNTs (Thomas Swan & Co. Ltd.) were steam- (4 h, 900 °C) and HCl-treated to remove carbonaceous impurities 57 , graphitic particles and metal particles (catalyst). The steam treatment also shortens the length of the SWCNTs, leading to a sample with a median length of 420 nm 58 . Short SWCNTs are of interest when developing delivery vehicles since they present an enhanced biocompatibility.…”