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An analytical solution for the effect of particle size on the current density and near-surface ion distribution around spherical nanoparticles is presented in this work. With the long-term aim to support predictions on corrosion reactions in the human body, the spherical diffusion equation was solved for a set of differential equations and algebraic relations for pure unbuffered and carbonate buffered solutions. It was shown that current densities increase significantly with a decrease in particle size, suggesting this will lead to an increased dissolution rate. Near-surface ion distributions show the formation of a steep pH-gradient near the nanoparticle surface (<6 μm) which is further enhanced in the presence of a carbonate buffer (<2 μm). Results suggest that nanoparticles in pure electrolytes not only dissolve faster than bigger particles but that local pH-gradients may influence interactions with the biological environment, which should be considered in future studies.
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Citation of this paper:
Thomas Stepan, Lisa Tété, Lila Laundry-Mottiar, Elena Romanovskaia, Yolanda S. Hedberg, Herbert Danninger, Michael Auinger, Effect of nanoparticle size on the near-surface pH-distribution in aqueous and carbonate buffered solutions, Electrochimica Acta, Volume 409, 2022, 139923, ISSN 0013-4686, https://doi.org/10.1016/j.electacta.2022.139923. (https://www.sciencedirect.com/science/article/pii/S0013468622000950)