疏水相互作用对阳离子聚电解质与染料键合的影响

用平衡渗析法研究了阳离子聚电解质PAm·MG 和P(St-Am·MG)与甲基橙(MO)及P(St-Am·MG)与MO的同系物乙基橙(EO)、橙武Ⅳ(O-Ⅳ)在25、35、45和55 ℃下相互作用的热力学. 由K1otz方程, 求得键合常数K_1和热力学参数ΔG、ΔH及ΔS. 含疏水基的P(St-Am·MG)与MO的键合能力比不含疏水基的PAm·MG 强. P(St-Am·MG)与不同染料作用时, 键合程度为O-Ⅳ>EO>MO, 即染料的疏水性越强, 与高聚物的作用程度越大.键合体系加入脲或甲醇, 疏水相互作用受到破坏, 导致高聚物与染料之间的键合受到削弱.

THE EFFECT OF HYDROPHOBIC INTERACTION ON THE CATIONIC POLYELECTROLYTE-DYE BINDING

The binding of cationic polyelectrolytes PAm·MG and P(St-Am·MG) with methyl orange(MO) and the binding of P(St-Am·MG) with MO homologue ethyl orange(EO) and orange-Ⅳ(O-Ⅳ) have been studied thermodynamically by the method of equi-librium dialysis at 25, 35, 45 and 55 ℃. The equilibrium constant K_1 and △H, △S, △G have been obtained. It has been found that the binding ability of P(St-Am·MG) is stronger than that of PAm·MG since the former contains hydrophobic group. The binding ability of dyes with P(St-Am·MG) is in the order: O-IV>EO>MO, i.e., the larger the hydrophobic group in the dyes, the stronger is the binding ability. When urea or methanol is added, the hydrophobic interaction of the polyelectrolyte and the dyes is destroyed resulting in weakening the polymer-dye binding.