Development of Quality Control Methods for Dispersibility and Stability of Single-Wall Carbon Nanotubes in an Aqueous Medium.

Moran Ben Basat,Noa Lachman

doi:10.3390/nano11102618

Abstract

The attractive properties of single-wall carbon nanotubes (SWCNT) such as mechanical strength and high electrical and thermal conductivity are often undercut by their agglomeration and re-agglomeration tendencies. As a result, the application of SWCNT as additives in advanced composite materials remain far from their potential, with proper dispersion being the major inhibitor. This work presents a dispersion quality control approach for water-based SWCNT dispersions (dispersed by a unique combination of physical and chemical methods), using complementary and easily scalable, characterization methods. UV-Vis spectroscopy, rheological measurements, and precipitant sheet resistance were used to understand the properties of the initial solution through processing and application. From an industrial perspective, these methods are fast and easy to measure while giving a repetitive and quick indication of dispersion quality and stability. The methods were correlated with microscopy and Raman spectroscopy to validate dispersion and SWCNT quality under various dispersing energies. The protocol was then applied to estimate the stability of SWCNT solutions, as well as the effectiveness of different surfactants in aiding dispersion. The simple, fast, and scalable combination of different characterizations provides good SWCNT dispersion and can be used as a quality control system for industrial production and usage.

Highlights

The ters, comparison between different becomes easier, which resonance ratio andcan the normal spectral width are two quantitative be an advantage in terms of quality control method
Investing further energy in dispersion resulted in damage to the tubes, indicated by further increase in absorbance intensity and sheet resistance, as well as further decrease in viscosity
The results showed a mostly stable dispersion in terms of optical and electrical properties, with the more sensitive rheology suggesting the beginning of precipitation

Summary

Introduction

In particular, are known for their properties of high mechanical strength, electrical conductivity, and thermal conductivity [1] Such properties make SWCNT ideal for various commercial applications such as solar panels [2], hydrogen storage [3], conductive inks for flexible displays [4], low-weight conductive reinforcements in polymers [5], electrochemical active materials for supercapacitors [6], biofuel cells [7], adhesive materials [8], and more. To harness these properties, SWCNTs often need to be integrated into a medium (either solid or liquid) and should be individually dispersed. High quality stable dispersion still presents a challenge, as the high surface area of SWCNT makes them susceptible to aggregation, driven by strong Van der Waals forces [1,9]

Methods

Results

Conclusion