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Dynamic light scattering investigations of nanoparticle aggregation following a light-induced pH jump

Published

Author(s)

Ryan Murphy, Denis Pristinski, Kalman D. Migler, Jack F. Douglas, Vivek Prabhu

Abstract

We use dynamic light scattering to characterize the kinetics of nanoparticle aggregation. The aggregation process was conveniently initiated in photoacid generator (PAG) solutions where changes in the pH of the solution can be controlled by exposure to ultraviolet light without the delays from mixing or stirring. The nanoparticle aggregation kinetics is extremely sensitive to the solution pH and we find that the UV exposure dose is inversely correlated to the surface charge of the nanoparticles, effectively decreasing the electrostatic repulsion force between particles leading to aggregation. The reaction-limited or diffusion-limited aggregation kinetics were sensitive to the pH quench depth, relative to the acid-equilibrium constant (pKa) of the surface carboxylic acid groups on the nanoparticles. Since numerous PAGs are commercially available, this approach could be used to study the aggregation of variety of solvent-dispersed nanoparticle systems.
Citation
Journal of Chemical Physics

Keywords

nanoparticle, stability, light scattering, pH, aggregation

Citation

Murphy, R. , Pristinski, D. , Migler, K. , Douglas, J. and Prabhu, V. (2010), Dynamic light scattering investigations of nanoparticle aggregation following a light-induced pH jump, Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=904974 (Accessed April 18, 2024)
Created May 18, 2010, Updated October 12, 2021