Effects of Various Surfactants on the Dispersion of MWCNTs-OH in Aqueous Solution.

Hongzhi Cui,Feng Xing,Manuel Monasterio,Xiantong Yan

doi:10.3390/nano7090262

Abstract

Dispersion of carbon nanotubes (CNTs) is a challenge for their application in the resulting matrixes. The present study conducted a comparison investigation of the effect of four surfactants: Alkylphenol polyoxyethylene ether (APEO), Silane modified polycarboxylate (Silane-PCE), I-Cationic polycarboxylate (I-C-PCE), and II-Cationic polycarboxylate (II-C-PCE) on the dispersion of hydroxyl functionalized multi-walled carbon nanotubes (MWCNTs–OH). Among the four surfactants, APEO and II-C-PCE provide the best and the worst dispersion effect of CNTs in water, respectively. Dispersion effect of MWCNTs–OH has been characterized by optical microscope (OM), field emission-scanning electron microscope (FE-SEM), and Ultraviolet–visible spectroscopy (UV–Vis).The OM images are well consistent with the UV–Vis results. Based on the chemical molecular structures of the four surfactants, the mechanism of MWCNTs–OH dispersion in water was investigated. For each kind of surfactant, an optimum surfactant/MWCNTs–OH ratio has been determined. This ratio showed a significant influence on the dispersion of MWCNTs–OH. Surfactant concentration higher or lower than this value can weaken the dispersion quality of MWCNTs–OH.

Highlights

IntroductionAccording to the layer number, they are classified as either single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs)
Carbon Nanotubes (CNTs) are regarded as a one-dimensional carbon nanomaterial
Comparative experiments have been conducted to study the difference in the dispersing capacities of four surfactants, namely Alkylphenol polyoxyethylene ether (APEO), Silane-PCE, I-Cationic polycarboxylate (I-C-PCE), and II-C-PCE

Summary

Introduction

According to the layer number, they are classified as either single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs). CNTs can be defined as rolled up from a single planar sheet of graphene, in the case of SWCNTs, and multi planar sheets in MWCNTs. Since the CNTs were discovered occasionally by Iijima in 1991 [1], great interests have been attracted by its superb mechanical [2], electric [3], thermal [4], and optical [5] properties, and various applications in bio-sensors [6], composites [7], field emission devices [8], energy or gas storage [9], and probe tips [10] etc. The energies of tube-tube contact by van der Waals are as high as 500 eV/μm [14]. For such high interaction energy, it is a challenging task to disperse CNTs uniformly

Objectives

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Results

Conclusion