Liquid–Liquid Phase Separation in Supermicrometer and Submicrometer Aerosol Particles

• DOI: 10.1021/acs.accounts.0c00093
• Publication Date: 2020-05-20T17:08:30Z
• Authors: Miriam Arak Freedman
• Keywords: Separation (statistics); Liquid phase; Liquid liquid

ConspectusThe interactions of aerosol particles with light and clouds are among the most uncertain aspects anthropogenic climate forcings. The effects on depend their optical properties, heterogeneous chemistry, water uptake behavior, ice nucleation activity. These properties in turn physics chemistry including composition, size, shape, internal structure (morphology), phase state. greatest numbers found at small, submicrometer sizes, can differ nanoscale compared measurements bulk materials. As a result, our focus has been characterizing transitions both supermicrometer particles. transition particular interest for us liquid–liquid separation (LLPS), which occurs when components solution separate due to difference solubilities. For example, organic compounds have limited solubility salt solutions especially as content decreases, increasing concentration solution, causing between organic-rich inorganic-rich phases. To characterize systems interest, we primarily use microscopy cryogenic-transmission particles.This Account details main results date morphology aerosol. We that relative humidity (RH) LLPS (separation RH; SRH) is highly sensitive composition particles, SRH decreases pH lowered atmospherically relevant values. also non-phase-separating added size dependence observed undergo In limit slow drying rates, <30 nm homogeneous larger phase-separated. This arises because small cannot overcome activation barrier needed form new by growth mechanism. inhibition mixtures ammonium sulfate single well complex organics like α-pinene secondary matter. affects diameters formation cloud condensation nuclei. more generally implications affect system. addition, widely studied materials biological could potentially translate these fields.