Synthesis and characterization of alkyl ester functionalized multiwall carbon nanotubes

Alkyl chains of different length were added onto surface of multiwall carbon nanotubes (MWCNT). Oxidized multiwall carbon nanotubes (MWCNT-COOH) were reacted with thionyl chloride (SOCl2) and further in esterification reaction with given alcohols gave corresponding methyl ester (MWCNT- COOCH3), n-butyl ester (MWCNT-COOC4H9) and n-dodecyl ester (MWCNT-COOC12H25) modified carbon nanotubes. Functionalization of MWCNTs was confirmed by FTIR, Raman and X-ray photoelectron spectroscopy as well as by thermogravimetric analysis. n-Butyl ester and n-dodecyl ester modified carbon nanotubes showed contact angle for water of about 142 and 150 degrees, while the oxidized and methyl ester modified carbon nanotubes showed seepage. Dispersibility of oxidized and alkyl ester modified carbon nanotubes in methanol and toluene was quantified by UV-Vis spectroscopy and differs significantly in both solvents for all systems.