TY - JOUR
T1 - Hygroscopicity of mixed glycerol/Mg(NO3)2/Water droplets affected by the interaction between magnesium ions and glycerol molecules
AU - Wang, Yang
AU - Ma, Jia Bi
AU - Zhou, Qiang
AU - Pang, Shu Feng
AU - Zhang, Yun Hong
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/4/30
Y1 - 2015/4/30
N2 - Tropospheric aerosols are usually complex mixtures of inorganic and organic components, which can influence the hygroscopicities of each other. In this research, we applied confocal Raman technology combined with optical microscopy to investigate the relationship between the hygroscopic behavior and the molecular interactions of mixed glycerol/Mg(NO3)2/water droplets. Raman spectra provide detailed structural information about the interactions between glycerol molecules and Mg2+ ions, as well as information about the interactions between glycerol and NO3- ions through electrostatic interaction and hydrogen bonding. The change of the CH2 stretching band of glycerol molecules in mixed droplets suggests that the backbone structures of glycerol mainly transform from αα to γγ in the dehumidifying process, and the additional Mg2+ ions strongly influence the structure of glycerol molecules. Because the existence of glycerol suppresses the crystallization of Mg(NO3)2·6H2O in the dehumidifying process, Mg(NO3)2 molecules in mixed droplets form an amorphous state rather than forming crystals of Mg(NO3)2·6H2O when the relative humidity is lower than 17.8%. Moreover, in mixed droplets, the molar ratio of NO3- to glycerol is higher in the center than in the outer region.
AB - Tropospheric aerosols are usually complex mixtures of inorganic and organic components, which can influence the hygroscopicities of each other. In this research, we applied confocal Raman technology combined with optical microscopy to investigate the relationship between the hygroscopic behavior and the molecular interactions of mixed glycerol/Mg(NO3)2/water droplets. Raman spectra provide detailed structural information about the interactions between glycerol molecules and Mg2+ ions, as well as information about the interactions between glycerol and NO3- ions through electrostatic interaction and hydrogen bonding. The change of the CH2 stretching band of glycerol molecules in mixed droplets suggests that the backbone structures of glycerol mainly transform from αα to γγ in the dehumidifying process, and the additional Mg2+ ions strongly influence the structure of glycerol molecules. Because the existence of glycerol suppresses the crystallization of Mg(NO3)2·6H2O in the dehumidifying process, Mg(NO3)2 molecules in mixed droplets form an amorphous state rather than forming crystals of Mg(NO3)2·6H2O when the relative humidity is lower than 17.8%. Moreover, in mixed droplets, the molar ratio of NO3- to glycerol is higher in the center than in the outer region.
UR - http://www.scopus.com/inward/record.url?scp=84928969130&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcb.5b00458
DO - 10.1021/acs.jpcb.5b00458
M3 - Article
AN - SCOPUS:84928969130
SN - 1520-6106
VL - 119
SP - 5558
EP - 5566
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 17
ER -