Institute for Atmospheric and Climate Science (IAC), ETH Zurich, Switzerland.
J Chem Phys. 2012 Feb 21;136(7):074515. doi: 10.1063/1.3685902.
Glass transition temperatures T(g) are investigated in aqueous binary and multi-component solutions consisting of citric acid, calcium nitrate (Ca(NO(3))(2)), malonic acid, raffinose, and ammonium bisulfate (NH(4)HSO(4)) using a differential scanning calorimeter. Based on measured glass transition temperatures of binary aqueous mixtures and fitted binary coefficients, the T(g) of multi-component systems can be predicted using mixing rules. However, the experimentally observed T(g) in multi-component solutions show considerable deviations from two theoretical approaches considered. The deviations from these predictions are explained in terms of the molar excess mixing entropy difference between the supercooled liquid and glassy state at T(g). The multi-component mixtures involve contributions to these excess mixing entropies that the mixing rules do not take into account.
采用差示扫描量热仪研究了柠檬酸、硝酸钙（Ca(NO(3))(2)）、丙二酸、棉子糖和硫酸氢铵（NH(4)HSO(4))组成的水基二元和多元组分溶液的玻璃化转变温度 T(g)。基于二元水混合物的测量玻璃化转变温度和拟合二元系数，可以使用混合规则来预测多组分系统的 T(g)。然而，在多组分溶液中观察到的实验 T(g)与所考虑的两种理论方法存在相当大的偏差。这些偏差可以根据玻璃化转变温度 T(g)下过冷液体和玻璃态之间的摩尔过剩混合熵差来解释。多组分混合物的这些过剩混合熵的贡献是混合规则没有考虑到的。
