Hyperbranched poly(triazole) with thermal and metal ion dual stimuli-responsiveness

Abstract

Oligo(ethylene glycol)-terminated hyperbranched poly(triazole) (hb-PTA-OEG) with thermal and metal ion dual stimuli-responsiveness was synthesized by Cu(I)-catalyzed azide–alkyne cycloaddition polymerization, which possessed a high molecular weight (M_n = 203 kDa) and good thermal properties (T_d = 367 °C, T_g = −14.1 °C). Importantly, hb-PTA-OEG exhibited a relatively low cloud point (CP) temperature ranging from 34.4 to 31.1 °C as the concentration was increased from 0.02 to 2.0 wt%. Simultaneously, hb-PTA-OEG has the ability to coordinate with various metal ions, and the type of metal ions influenced the CP of hb-PTA-OEG solution to some extent as a result of their different association strengths with the polymer, particularly, Ag⁺ ion showed a conspicuous contribution to increasing the CP among the several selected ions. As a result, hb-PTA-OEG can act as an absorber of metal ions, and the selective absorption of Ag⁺ ion could be reached by tuning temperature.