Functionalisation of multi-walled carbon nanotubes by esterification method for poly(ethylene)glycol attachment and their characterization

Abstract

In this study, we have successfully functionalised multi-walled carbon nanotubes (MWCNT) surfaces with poly(ethylene)glycol (PEG) via an esterification method in which the oxygenated functional groups are created by chemical oxidations with a mixture of nitric acid and sulfuric acid solutions (ratio of 1:3, v/v), and then it is reacted with functional groups of PEG. Different techniques including FE-SEM, TEM, EDS, FT-IR spectrometry, Raman spectroscopy and TGA are applied to identify the characteristics of MWCNTs. The effects of catalyst and different mass ratios of PEG:MWCNTs on the characteristics of MWCNTs are investigated for the first time. The TGA analysis indicates that when the mass ratio of PEG:MWCNTs is 140:1, the highest weight loss of 30.86 wt% is obtained. Additionally, an increase in the amounts of catalysts decreases the content of PEG attached on the nanotubes. The catalyst of 0.3 ml H 2 SO 4 and the mass ratio of PEG:MWCNTs=140:1 demonstrates to be the most effective for PEG functionalised MWCNTs. It can be chosen as the best experimental conditions to perform PEG functionalised MWCNTs.

Carbon Nanotubes in Tumor-Targeted Chemotherapeutic Formulations: A Review of Opportunities and Challenges

“…The main goal of preparing oxCNTs is to obtain polar structures to avoid aggregation associated with cytotoxicity. Further functionalization of oxCNTs can introduce other functionalities through direct esterification using alcohols. − This can be chosen as the best experimental condition to prepare PEG-functionalized CNTs …”

“…208−212 This can be chosen as the best experimental condition to prepare PEG-functionalized CNTs. 213 The chemistry for functionalization of CNTs includes methods of amidation. In particular, it was shown that the direct solvent-free amination designed by Basiuk and coworkers 214−217 facilitates oxCNTs to react with amines, avoiding organic solvents, which is ideal for applications in nanomedicine.…”