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Publication abstract: Atmospheric aerosols’ effects on the Earth’s climate and atmosphere can vary significantly depending on their properties including size, morphology, and phase state, all of which are influenced by varying relative humidity (RH) in the atmosphere. Furthermore, a significant fraction of atmospheric aerosols is below 100 nm in size (i.e., nanoparticles). However, due to size limitations of conventional experimental techniques, the atmospheric role of sub-100 nm aerosols and how the particle-to-particle variability of the phase state affects atmospheric processes are poorly understood. To address this issue, the atomic force microscopy (AFM) methodology that was previously established for submicrometer aerosols is extended to measure the water uptake and identify the phase state of individual sucrose nanoparticles. Quantified 3D hygroscopic growth factors of individual sucrose nanoparticles at 60% RH were lower than expected values observed on the submicrometer sucrose particles. Specifically, the growth factor of sucrose nanoparticle (height of 50 nm) was 0.89, which is approximately 18% lower than the expected value of 1.08. The effect was attributed to the nanoparticle restructuring on a solid substrate. Despite this however, the identified phase states of the nanoparticles were comparable to their submicrometer counterparts. The identified phase transition between solid to semisolid, and semisolid to liquid were at ~18% and 60% RH, which would be equivalent to viscosities of 1011.2 Pa s and 102.5 Pa s, respectively. This work demonstrates that measurements of the phase state using AFM is applicable to nanosized particles, even when the substrate alters the shape of semisolid nanoparticles at elevated RH. Research Data Curation Program, UC San Diego, La Jolla, 92093-0175 (https://lib.ucsd.edu/rdcp) Madawala, Chamika K.; Lee, Hansol D.; Kaluarachchi, Chathuri P.; Tivanski, Alexei V. (2021). Data from: Probing the water uptake and phase state of individual sucrose nanoparticles using atomic force microscopy. In Center for Aerosol Impacts on Chemistry of the Environment (CAICE). UC San Diego Library Digital Collections. https://doi.org/10.6075/J0S46QG6
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Nanoparticles Aerosol particles Relative humidity Phase state Sucrose Atomic force microscopy