Quantitative Characterization of the Colloidal Stability
of Metallic Nanoparticles Using UV–vis Absorbance Spectroscopy
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Abstract
Plasmonic nanoparticles are used
in a wide variety of applications
over a broad array of fields including medicine, energy, and environmental
chemistry. The continued successful development of this material class
requires the accurate characterization of nanoparticle stability for
a variety of solution-based conditions. Although many characterization
methods exists, there is an absence of a unified, quantitative means
for assessing the colloidal stability of plasmonic nanoparticles.
We present the particle instability parameter (PIP) as a robust, quantitative,
and generalizable characterization technique based on UV–vis
absorbance spectroscopy to characterize colloidal instability. We
validate PIP performance with both traditional and alternative characterization
methods by measuring gold nanorod instability in response to different
salt (NaCl) concentrations. We further measure gold nanorod stability
as a function of solution pH, salt, and buffer (type and concentration),
nanoparticle concentration, and concentration of free surfactant.
Finally, these results are contextualized within the literature on
gold nanorod stability to establish a standardized methodology for
colloidal instability assessment