混合模型膜有序度参数与活度系数的关系

针对以往关于混合模型膜热力学的有序度参数与活度系数相互关系的经验性，从有序度参数的统计力学意义出发，应用平均场近似，通过经典热力学方法讨论了混合模型膜体系中有序度参数与活度系数两者之间的关系，并求得了其理论表达式。

On Order Parameters and Activity Coefficients of Mixed Model Membranes

In this paper, a theoretical analysis on the relation between order parameters and activity coefficients of mixed model membranes is presented to overcome its empiricism in the previous studies- On the basis of statistical mechanics of order parameter, our discussion employs the mean-field approximation and leads, by means of classic thermodynamics, to a theoretical expression which demonstrates the concerned relation. Then a primary test that calculates the activity coefficients of POPC of system cholesterol/POPC (1-palmitoyl-2-oleoyl-sn-glycero-phosphatidylch by the proposed expression is carried out- Calculated values of activity coefficients for two concentrations at five temperatures are obtained. Com-pared to the.literature method, this work can better represent the behavior that activity coef-ficient changes with respect to temperature. In addition, the result shows that activity coeffi-cients are not sensitive to temperature within the given range of temperature. This indicates that the effect of temperature upon molecular interaction in the lipid bilayer of cholesterol/POPC is not s'ignificant.