Ambient solid-state mechano-chemical reactions between functionalized carbon nanotubes.

Mohamad A Kabbani,Pedro A.S Autreto,Chandra Sekhar Tiwary,Anirban Som,Sehmus Ozden,K.R Krishnadas,Thalappil Pradeep,Pulickel M Ajayan,Robert Vajtai,Ahmad T Kabbani,Ken P Hackenberg,Gustavo Brunetto,Yongi Gong,Douglas S Galvao

doi:10.1038/ncomms8291

Abstract

Carbon nanotubes can be chemically modified by attaching various functionalities to their surfaces, although harsh chemical treatments can lead to their break-up into graphene nanostructures. On the other hand, direct coupling between functionalities bound on individual nanotubes could lead to, as yet unexplored, spontaneous chemical reactions. Here we report an ambient mechano-chemical reaction between two varieties of nanotubes, carrying predominantly carboxyl and hydroxyl functionalities, respectively, facilitated by simple mechanical grinding of the reactants. The purely solid-state reaction between the chemically differentiated nanotube species produces condensation products and unzipping of nanotubes due to local energy release, as confirmed by spectroscopic measurements, thermal analysis and molecular dynamic simulations.

Highlights

Carbon nanotubes can be chemically modified by attaching various functionalities to their surfaces, harsh chemical treatments can lead to their break-up into graphene nanostructures
Carbon nanotubes (CNTs)-COOH can further be activated by acylation to form CNT-COCl, which can in turn be amidated or esterified[13,14]
We report the demonstration of unzipping of CNTs via a solid-state room temperature reaction between multiwalled CNTs (MWCNTs) containing different reactive functionalities of COOH and OH groups

Summary

Introduction

Carbon nanotubes can be chemically modified by attaching various functionalities to their surfaces, harsh chemical treatments can lead to their break-up into graphene nanostructures. We report an ambient mechano-chemical reaction between two varieties of nanotubes, carrying predominantly carboxyl and hydroxyl functionalities, respectively, facilitated by simple mechanical grinding of the reactants. A typical chemical unzipping of CNTs makes use of oxidative techniques[31] in concentrated acid (H2SO4) and post treatments with harsh reagents such as highly concentrated potassium permanganate (KMnO4). These processes involve harsh conditions to get to the final product (graphene), which can contain broken up or unzipped CNT. We report the demonstration of unzipping of CNTs via a solid-state room temperature reaction between multiwalled CNTs (MWCNTs) containing different reactive functionalities of COOH and OH groups. Where G and G0 represent the graphenes originating from the carboxylic and hydroxyl MWCNT (functionalized MWCNTs)

Methods

Results

Conclusion