Highly efficient individual dispersion of single-walled carbon nanotubes using biocompatible dispersant

Individual dispersion of single-walled carbon nanotubes (SWNTs) in biocompatible media is of particular interest for diverse biomedical and nanomedicine applications. Herein we present, for the first time, a neutral pH water-soluble chitosan derivative, chitosan-hydroxyphenyl acetamide (CHPA), prepared by functionalizing the amino groups of chitosan with 4-hydroxyphenyl acetic acid, as an efficient biocompatible dispersant to effectively debundle and individually disperse SWNTs in a neutral aqueous solution. For efficient individual dispersion of SWNTs, various process conditions such as centrifugation speed, sonication power, and CNT:dispersant ratio were optimized based on characterizations by atomic force microscopy, optical absorption spectroscopy, and Raman spectroscopy. Evaluation of the SWNT–CHPA solution showed superior individual dispersion to samples prepared using other biocompatible dispersants. The highly efficient individual dispersion of SWNTs with the biocompatible dispersant opens up possibilities for its applications in the bio- and nanomedical fields.