NaCl在聚电解质溶液中活度系数的实验测定

引　言聚电解质是指在极性溶剂中能够电离形成聚离子和反离子的高分子1] ,在生物体中广泛存在 ,如蛋白质、ＤＮＡ和ＲＮＡ等都是聚电解质 ,聚丙烯酸盐和聚苯乙烯磺酸盐则是典型的人工合成聚电解质 .在聚电解质的水溶液中 ,由于聚离子带有大量的电荷 ,对反离子具有很强的静电吸引作用 ,即使在极低的浓度下溶液仍具有很大的非理想性 ,这与普通电解质溶液显著不同2 ,3 ] .建立聚电解质溶液热力学性质的计算方法一直是溶液理论研究的热点 ,现已取得长足进展 ,如Ｍａｎｎｉｎｇ的反离子凝聚理论2 ,3 ] 、柱状胞腔模型基础上的ＰＢ方程理论4 ,…

MEASUREMENT OF MEAN ACTIVITY COEFFICIENTSOF NaCl IN POLYELECTROLYTE SOLUTIONS

Electromotive force measurements of the cell, Na-ISE|polyelectrolyte( m p(mono) ),NaCl( m a)|AgCl,Ag,are carried out at the different molalities of NaCl in aqueous poly(diallydimethylammonium chloride)(PDADMAC)and poly(anetholesulfonic acid, sodium salt)(PAS) solutions at 308.15 K. The mean activity coefficients of NaCl in aqueous polyelectrolyte solutions are determined by using the standard cell potential which are obtained from the measurements of the electromotive force of cell,Na-ISE| NaCl( m )|AgCl, Ag, combining with the Pitzer model for electrolyte solution.At different concentrations of PDADMAC solution, the mean activity coefficients of NaCl decrease monotonically as the concentrations of NaCl increase.However, for the aqueous solutions of PAS, there is a maximum value as the concentrations of NaCl increase.