丁二酸气溶胶吸湿生长后结构和界面的分子动力学模拟

基于分子动力学方法模拟了丁二酸气溶胶的吸湿生长现象，研究了温度和水含量对颗粒平衡后结构和界面特性的综合影响机制。结果表明，温度和水含量会影响丁二酸的溶剂化分子数，从而导致颗粒吸湿生长后呈现水包酸的分层结构、混合结构和酸包水的分层结构。颗粒表面丁二酸含量随温度的升高先增加后减少，且随水含量的增加而增加。此外，温度高于260 K时，颗粒表面丁二酸分子的亲水基和疏水基分别朝向颗粒内部和气相。

Molecular dynamics simulation on the structure characteristics of succinic acid aerosols after hygroscopic growth

The hygroscopic growth of aerosols has significant effects on their environmental behaviors and health effects. However, the knowledge on the microscopic kinetic mechanism for hygroscopic growth of aerosols containing surface active components has been largely lacking. In this study, the hygroscopic growth of succinic acid aerosol particle was simulated using the molecular dynamics method. The key point is to investigate the combined effects of temperature and water content on the structure and interface characteristics of particles at the equilibrium state. Results show that temperature and water content can affect the solvation number of succinic acid, resulting in the occurrence of the layered structure with water wrapping around acid particle, the mixed structure and the layered structure with acid wrapping around water droplet. The distribution of succinic acid on the surface region increases first and then decreases, and it increases with the increasing water content. Additionally, when the temperature is greater than 260 K, the hydrophilic and hydrophobic group of succinic acid molecules on the particle surface are toward the particle inside and the gas phase, respectively.