采用重量分析法对达到溶胀平衡的AA/AMPS、AA/DMAEMA和AMPs/DMAEMA共聚物水凝胶在金属离子溶液中体积收缩变化的动力学过程进行了研究,结果表明:共聚物水凝胶在4种金属离子(Ag+、Cu2+、Fe3+、Pb2+)溶液中均发生体积收缩的响应变化,并且这种变化程度随着金属离子溶液浓度的增加而增加,由“指数衰减第一顺序”函数可以较好地拟合水凝胶体积收缩响应过程的实验数据;在相同的金属离子浓度下,AA/AMPs、AA/DMAEMA和AMPS/DMAEMA水凝胶的平衡体积收缩比(V∞/V0)和消溶胀速率常数Ka大小顺序总体一致,分别为Fe3+〉Pb2+〉Cu2+〉Ag+、Cu2+〉Fe3+〉Pb2+〉Ag+和Pb2+〉Fe3+〉Cu2+〉Ag+。通过“孤对电子-空轨道”理论从结构上解释了水凝胶在不同价态重金属溶液中的消溶胀机理;AA/AMPS-Fe3+体系、AA/DMAEMA—Cu2+体系和AMPS/DMAEMA-Pb2+体系体积收缩过程的活化能Ea分别为3.081、1.86、1.917kJ·mol^-1。
De-swelling kinetics of swollen copolymer hydrogels (AA/AMPS, AA/DMAEMA and AMPS/ DMAEMA) in metallic ion (Ag+ , Cu2+ , Fe3+ and Pb2+ ) solutions was investigated with gravimetry. The copolymer hydrogels showed responsive volumetric shrinking behavior in Ag+, Cu2+, Fe3+ and Pb2+ metallic ion solutions, and the extent of de-swelling increased with increasing metallic ion concentration. By using a decaying exponential first-order function, the volume shrinking process of the hydrogels could be well fitted with the correlation coefficient above 0.98. At a fixed concentration of metallic ion, the equilibrium volume shrink ratios (V∞/Vo) of AA/AMPS, AA/DMAEMA and AMPS/DMAEMA hydrogels were in the order Fe3+ 〉Pb2+ 〉Cu2+ 〉Ag+, Cu2+ 〉Fe3+ 〉Pb2+ 〉Ag+ , and Pb2+ 〉Fe3+ Cu2+ 〉Ag+ , respectively, and so did the de-swelling rate constant. In addition, a mechanism, "lone pairs of electrons-unoccupied orbitals" was proposed for the gel volume shrinking process, in which the energy of activation values of AA/AMPS-Fe3+ , AA/DMAEMA-Cu2+ , and AMPS/DMAEMA-Pb2+ system were 3. 081, 1.86, and 1. 917 kJ · mol^-1 , respectively.