– PI: Markus Petters
– Source: National Science Foundation
– Graduate Students: Sundandan Mahant
Overview. Atmospheric particles between 10 and 100 nm in diameter play a central role in atmospheric chemistry by providing surface and volume for multiphase reactions to proceed. In many environments these particles are crystalline or glassy solids. As particle size approaches the molecular scale, strong curvature of the particle air interface leads to a depression of the melting point, known as the Gibbs-Thompson effect. This proposal seeks to quantify how particle diameter influences the crystalline solid-liquid and amorphous solid-liquid phase transitions. Particle-dimers will be created through coagulation. The temperature required to induce particle coalescence will be measured as a function of particle diameter between 10 and 100 nm. This temperature corresponds to the melting of a semi-solid with viscosity of 10^6 Pa s. The measurements will be used to constrain the temperature dependence of viscosity and the glass transition temperature of the particles. Investigated compositions will include single component model systems and multi-component model blends, mimicking common atmospheric aerosol. The main objective of the work is to quantify the Gibbs-Thomson effect for amorphous viscous or glassy particles.
Relevant Publications
Mahant, S. Snider, J.R., Petters, S. S. and Petters, M. D.: Effect of aerosol size on glass transition temperature, J. Phys. Chem. Lett., 15 (29), 7509-7515, doi:10.1021/acs.jpclett.4c01415, 2024.
Mahant, S., Iversen, E. M., Kasparoglu, S., Bilde, M., and Petters, M. D.: Direct measurement of the viscosity of ternary aerosol mixtures, Env. Sci Atmos, 3, 595–607, https://doi.org/10.1039/D2EA00160H, 2023.
Petters, M. D. and Kasparoglu, S.: Predicting the influence of particle size on the glass transition temperature and viscosity of secondary organic material, Sci. Rep., 10, 15170, https://doi.org/10.1038/s41598-020-71490-0, 2020.