046

Title:

Shape-Controlled Dissolution of Silver Nanoparticles, a Case Study by SECMAFM

Discipline: Materials engineering

Presenter:

Qingquan Ma

Abstract:

Silver nanoparticles (Ag NPs) are receiving a great deal of attention in the scientific and regulatory communities because of their use in commercial products and release to the environment. Ag NPs are reportedly being incorporated into consumer products at a faster rate than any other nanomaterial. The properties of Ag NPs are key to understanding their biological activity and the environmental implications of their release. Studies have shown that size, shape, surface coating, and solution chemistry all influence Ag NPs toxicity. Most researcher have suggested that the biological activity of Ag NPs is controlled by Ag+ release rates, which, in turn, are controlled by size, shape, and surface coating. In this study, some emerging novel technologies (i.e., Combined scanning electrochemical- atomic force microscopy (SECM-AFM), High-resolution transmission electron microscopy (HR-TEM)) combined with traditional methods (i.e., Scanning Electron Microscopy (SEM), X-ray powder diffraction (XRD)) were adopted in the characterization of Ag NPs properties. SECM is very useful as a technique for quantitatively investigating the dissolution characteristics of nanomaterials. AFM is one of the most attractive and unparalleled means that could characterize in situ surface properties at a nanometer vertical resolution. Combined SECM-AFM for imaging under fluids, capable of providing simultaneous topographical and electrochemical measurements, with high spatial resolution. Meanwhile, the facet identification, indexing, and individual facet surface areas will be determined statistically from HR-TEM. Combined with SEM and XRD technologies, it can also characterize the surface morphology of nanoparticles and further identify their crystallinity. This may provide reasonable estimates of Ag NP aqueous solubility with different shapes.

Author(s):

Qingquan Ma, Xiaonan Shi, Wen Zhang

Funding Acknowledgements:

This work is funded by the national science foundation (Award Number: 1756444) via Biological & Environmental Interfaces of Nano Materials, the USDA National Institute of Food and Agriculture, AFRI project [2018-07549] and Assistance Agreement No. 83945101-0 awarded by the U.S. Environmental Protection Agency to New Jersey Institute of Technology.