Dispersion of Nanomaterials in Aqueous Media: Towards Protocol Optimization.

Laura-Jayne Ellis,Annegret Potthoff,Marie Carriere,Ratna Tantra,Caterina Minelli,Inder Kaur,Wolfgang Unger,Isabella Romer,Eugenia Valsami-Jones,Soline Allard,Martine Mayne-L'Hermite,Steffi Rades

doi:10.3791/56074

Abstract

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and stability of the suspension. In this study, a systematic step-wise approach is carried out to identify optimal sonication conditions in order to achieve a stable dispersion. This approach has been adopted and shown to be suitable for several nanomaterials (cerium oxide, zinc oxide, and carbon nanotubes) dispersed in deionized (DI) water. However, with any change in either the nanomaterial type or dispersing medium, there needs to be optimization of the basic protocol by adjusting various factors such as sonication time, power, and sonicator type as well as temperature rise during the process. The approach records the dispersion process in detail. This is necessary to identify the time points as well as other above-mentioned conditions during the sonication process in which there may be undesirable changes, such as damage to the particle surface thus affecting surface properties. Our goal is to offer a harmonized approach that can control the quality of the final, produced dispersion. Such a guideline is instrumental in ensuring dispersion quality repeatability in the nanoscience community, particularly in the field of nanotoxicology.

Highlights

Sonication is the process of generating cavitations, which involves the creation, growth, and collapse of bubbles formed in liquid due to the irradiation of high intensity ultrasound[1]
We present a comparative study of six different nanomaterial dispersions made using ultrasonic bath and an ultrasonic probe fitted with a vial tweeter
The ultimate goal of the study is to develop a strategy that would allow the identification of optimal sonication conditions to make dispersions of a selected number of nanomaterials in water

Summary

Introduction

Sonication is the process of generating cavitations, which involves the creation, growth, and collapse of bubbles (often called hot spots) formed in liquid due to the irradiation of high intensity ultrasound[1]. There are different sonicators, all having the general function of de-agglomerating particles, which disperse in a liquid medium as individual (or primary) particles. Sample homogeneity can improve, potentially achieving a much narrower particle size distribution. There are several ways to measure dispersion stability. This includes estimation of zeta potential (ZP) through measurement of electrophoretic mobility of particles. Another is to measure the characteristic absorption of nanoparticles in the UV spectral range[4]

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