Effects of Two Purification Pretreatments on Electroless Copper Coating over Single-Walled Carbon Nanotubes

Zhong Zheng,Sinian Li,Shijie Dong,Anchun Xiao,Lianjie Li,Shixuan Sun

doi:10.1155/2014/585983

Abstract

To achieve the reinforcement of copper matrix composite by single-walled carbon nanotubes, a three-step-refluxing purification of carbon nanotubes sample with HNO3-NaOH-HCl was proposed and demonstrated. A previously reported purification process using an electromagnetic stirring with H2O2/HCl mixture was also repeated. Then, the purified carbon nanotubes were coated with copper by the same electroless plating process. At the end, the effects of the method on carbon nanotubes themselves and on copper coating were determined by transmission electron microscope spectroscopy, scanning electron microscope spectroscopy, X-ray diffractometry, thermogravimetric analysis, Fourier transformed infrared spectroscopy, and energy dispersive spectrometry. It was clearly confirmed that both of the two processes could remove most of iron catalyst particles and carbonaceous impurities without significant damage to carbon nanotubes. The thermal stability of the sample purified by H2O2/HCl treatment was slightly higher than that purified by HNO3-NaOH-HCl treatment. Nevertheless, the purification by HNO3-NaOH-HCl treatment was more effective for carboxyl functionalization on nanotubes than that by H2O2/HCl treatment. The Cu-coating on carbon nanotubes purified by both purification processes was complete, homogenous, and continuous. However, the Cu-coating on carbon nanotubes purified by H2O2/HCl was oxidized more seriously than those on carbon nanotubes purified by HNO3-NaOH-HCl treatment.

Highlights

Single-walled carbon nanotubes (SWCNTs) have nearly perfect bonding structures and no adjacent walls
The samples for TEM were prepared by dropping the ethanol suspension of SWCNTs onto a grid which was left to air-dry
The results suggest that the two purification processes were useful for SWCNTs functionalization

Summary

Introduction

Single-walled carbon nanotubes (SWCNTs) have nearly perfect bonding structures and no adjacent walls. Chungchamroenkit et al [19] combined NaOH solution leaching and froth flotation to purify the SWCNTs synthesized by disproportionation of CO over a Co-Mo/SiO2 catalyst They found that most of the SWCNTs in sample were recovered without damaging the physical and chemical structures of SWCNTs. Most of the procedures concentrated on the reduction of metal and nonnanotube carbon impurity, the chemical modification (functionalization) of SWCNTs and the structural changes of SWCNTs. The influence of different purification techniques on the subsequent specific application has not been reported. The effects of the two purification methods on the SWCNTs themselves and on electroless Cucoating were determined by some modern analytical techniques and characteristic methods

Experimental

Results and Discussion

Conclusions