The morphology of aerosol particles impacts their role in the climate system. In the submicron size regime, the morphology of particles that undergo liquid-liquid phase separation is dependent on their size, where for some systems small particles are homogeneous and large particles are phase-separated. We use cryogenic transmission electron microscopy to probe the morphology of model organic aerosol systems. We observe that the transition region (where both homogeneous and phase-separated morphologies are seen) spans 121 nm at the fastest drying rates with a midpoint diameter > 170 nm. By slowing the drying rate over several orders of magnitude, the transition region shifts to smaller diameters (midpoint < 40 nm) and the width narrows to 4 nm. Our results suggest that the size-dependent morphology originates from an underlying finite size effect, rather than solely kinetics, due to the presence of a size dependence even at the slowest drying rates.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry