Viscosity and physical state of sucrose mixed with ammonium sulfate droplets

Abstract. Although knowledge of the physical state aerosol particles is essential to understand atmospheric chemistry model and measurements, information on viscosity consisting organic inorganic salts still rare. Herein, we quantified viscosities at 293 ± 1 K upon dehydration for binary systems, sucrose–H2O ammonium sulfate (AS)–H2O, ternary sucrose–AS–H2O organic-to-inorganic dry mass ratios (OIRs) = 4:1, 1:1, 1:4 using bead-mobility poke-and-flow techniques. Based value particles, defined states total studied in this work. For gradually increased from ∼ 4 × 10−1 > 108 Pa s when relative humidity (RH) decreased 81 % 24 %, ranging liquid semisolid or solid state, which agrees with previous studies. The AS–H2O remained (< 102 s) RH 50 while ≤∼ showed a 1012 s, corresponding state. In case organic-rich (OIR 4:1) decrease 18 similar particles. This indicates that range across RH. OIR ranged less than 34 27 correspond < %. Compared inorganic-rich 1:4), drastic enhancement was observed as decreased; by approximately 8 orders magnitude during 43 25 resulting range. Overall, all work were exist liquid, semisolid, depending Furthermore, compared measured systems OIRs predicted Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients Viscosity (AIOMFAC-VISC) predictions Zdanovskii–Stokes–Robinson (ZSR) organic–inorganic mixing model, excellent model–measurement agreement OIRs.