Abstract The hygroscopic behavior of complex mixed organic–organic and organic–inorganic particles consisting of various dry mass ratios of ammonium sulfate (AS), oxalic acid (OA), malonic acid (MA) and polyethylene glycol-300 (PEG) has been studied using a Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) setup. The measured growth factors (GFs) are compared to values predicted by the AIOMFAC-based thermodynamic equilibrium model and the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. The measured GFs for PEG–OA and PEG–MA systems are found to be significantly lower than those predicted by the two models, which assume the complete dissolution of the organic compounds. The observed behavior suggests that the presence of PEG substantially affects the solubility of organic acids and associated water uptake. For quinary systems containing PEG, organic acids, and AS, a complete deliquescence of the mixed particles is observed during hydration conditions at RH ~78–80% close to the deliquescence point of pure AS particles. A clear disagreement was observed between measurements and predictions from AIOMFAC and ZSR for hydration conditions prior to the full particle deliquescence. We provide indirect evidence for the presence of an organic solid alongside solid AS. Hypothetically, the observed disagreement could also be due to a preferential interaction between –COOH and –CH2OCH2- groups, which may prevent a fraction of the organic acid amount to interact with water. For fully deliquesced particles, good agreement between model predictions and measurements are found for the mixed PEG–organic acids–AS systems. Upon dehydration, when the mass fraction of PEG

中文翻译：

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无机-有机气溶胶系统的吸湿行为，包括硫酸铵、二羧酸和低聚物

摘要 研究了由不同干质量比的硫酸铵 (AS)、草酸 (OA)、丙二酸 (MA) 和聚乙二醇-300 (PEG) 组成的复杂有机-有机和有机-无机混合颗粒的吸湿行为。使用吸湿串联微分迁移率分析仪 (HTDMA) 设置。将测量的生长因子 (GF) 与基于 AIOMFAC 的热力学平衡模型和 Zdanovskii-Stokes-Robinson (ZSR) 混合规则预测的值进行比较。发现 PEG-OA 和 PEG-MA 系统测得的 GF 显着低于两个模型预测的值，这两个模型假设有机化合物完全溶解。观察到的行为表明 PEG 的存在显着影响有机酸的溶解度和相关的水吸收。对于含有 PEG、有机酸和 AS 的五元系统，在接近纯 AS 颗粒潮解点的 RH ~78-80% 的水合条件下观察到混合颗粒的完全潮解。观察到 AIOMFAC 和 ZSR 对完全颗粒潮解之前的水合条件的测量和预测之间存在明显的分歧。我们提供了在固体 AS 旁边存在有机固体的间接证据。假设，观察到的不一致也可能是由于 -COOH 和 -CH2OCH2- 基团之间的优先相互作用，这可能会阻止一部分有机酸量与水相互作用。对于完全潮解的颗粒，发现混合 PEG-有机酸-AS 系统的模型预测和测量值之间具有良好的一致性。脱水后，