Chemical modification of single-walled carbon nanotubes with peroxytrifluoroacetic acid

A new and simple method for chemical modification of single-walled carbon nanotubes (SWNTs) is presented. Purified SWNTs ropes prepared by CVD growth were reacted with peroxytrifluoroacetic acid (PTFAA) under ultrasonication. Samples before and after treatment were characterized using Raman, FTIR, UV/Vis/NIR, XPS, and AFM. Data from these experiments conclusively showed that, in addition to oxygen-based functional groups, trifluoroacetic groups were covalently attached to the SWNTs. Moreover, these modified SWNTs were shortened into ca. 300 nm in length in the same step of functionalization, resulting in exfoliation of nanotube ropes to yield small bundles and individual nanotubes. The resultant SWNTs were easily dispersed in polar solvents such as dimethylformamide, water and ethanol. The PTFAA treatment described herein should be useful to tailor SWNTs' chemical and physical properties and to broaden their chemical processibility and reactivity.