Electrospray synthesis and in-situ sizing of nanoparticulate CsH₂PO₄

Abstract

Nanometer-sized particles of the solid acid electrolyte material CsH₂PO₄ have been prepared by electrospray synthesis. Using a differential mobility analyzer to provide real-time particle-size information, the role of electrospray parameters, such as precursor solution composition, surface tension, and conductivity, sheath gas temperature and flow rate, and solution flow rate, were evaluated. The results are compared with particle sizes calculated using well-established scaling laws. The much smaller sizes of the detected particles in comparison to the sizes expected from the predicted initial droplet sizes suggests that droplets undergo fission along the path toward deposition. In flight fission events may also explain the observed counterintuitive result that aerosol particle size decreases with increasing solute concentration. The in situ feedback provided by this system enabled rapid identification of solution and process parameters that result in mean particle sizes of ∼15 nm, substantially smaller than any prior results.

Copyright © 2023 American Association for Aerosol Research

EDITOR:

• Mark Swihart

Acknowledgements

The authors thank Hyung Wan Do for assistance in performing sizing experiments, Berhanu (Hanu) Snyder for rendering Figure 3, and Andrew Green for validation of solubility limits, under the supervision of Dylan Bardgett, whose contributions are also gratefully acknowledged.

Disclosure statement

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Additional information

Funding

This work was funded through the generous support of the Resnick Sustainability Institute (California Institute of Technology) and the Ver Steeg Faculty Fellowship Program (Northwestern University). Additional support was provided by the National Science Foundation via award DMR 2118201.