两性聚电解质溶液的分子热力学模型和分子动力学模拟  

Molecular Thermodynamics Model and Molecular Dynamics Simulation of Polyampholyte Solutions

作　　者：冯剑[1] 刘洪来[1] 胡英[1] 

机构地区：[1]华东理工大学化学系化学工程国家重点实验室,上海200237

出　　处：《化学学报》2004年第3期247-252,共6页Acta Chimica Sinica

基　　金：国家自然科学基金 (Nos.2 0 0 2 561 8;2 0 2 360 1 0 );上海市教委资助项目

摘　　要：从带电硬球混合物出发采用化学缔合理论建立了聚电解质和两性聚电解质溶液的分子热力学模型 .用考虑溶剂的粘滞力和热浴随机力作用的分子动力学 (MD)方法模拟了聚电解质和两性聚电解质溶液的渗透系数 .对模型预测结果和MD模拟结果进行了比较 ,表明基于化学缔合理论的分子热力学模型可以用于聚电解质溶液和两性聚电解质溶液热力学性质的预测 ,对于均聚电解质溶液效果令人满意 ,对由直径不同的离子构成的聚电解质溶液 ,模型的预测效果变差 ,有待进一步改进 .Polyelectrolyte or polyampholyte solutions are modeled as freely tangent-jointed, charged hard-sphere chains and corresponding counterions in a continuum medium with permitivity. A molecular thermodynamic model is then derived from statistical mechanic theory for chemical association. Using molecular dynamics (MD) simulation considering viscous force from solvent and stochastic force from heat-bath, the osmotic coefficients of polyelectrolyte and polyampholyte solutions are obtained. The predicted osmotic coefficients by the molecular thermodynamic model are agreed with those by MD simulation for the homogeneous polyelectrolyte solutions and for polyampholyte solutions. However, the predicted results by theoretical model have some divergence for the heterogeneous polyelectrolyte solutions with different segment diameters of polyion, which shows that the molecular thermodynamic model of polyelectrolyte solutions should be farther improved. The predicted results for the osmotic coefficient of polyampholyte solution are better than the results of polyelectrolyte solution.

关 键 词：聚电解质溶液 两性聚电解质溶液 分子热力学模型 分子动力学 模拟 渗透系数 化学缔合理论 

分 类 号：O631[理学—高分子化学]