Water-soluble and redox-responsive hyperbranched polyether copolymers based on ferrocenyl glycidyl ether

Abstract

Water-soluble copolymers of ferrocenyl glycidyl ether (fcGE) and glycidol were prepared via anionic ring-opening multibranching polymerization (ROMBP). The resulting hyperbranched materials with molecular weights (M_n) of 3500 to 12 300 g mol⁻¹ and relatively narrow molecular weight distributions (M_w/M_n = 1.40–1.69) exhibit both temperature- as well as redox-responsive behavior, which was studied via turbidity measurements. The cloud point temperatures (T_c) were adjusted between 45 and 60 °C through variation of the fcGE comonomer content. Additionally, these T_cs can be increased by the addition of an oxidizing agent. The extent of oxidation of the materials was quantified by Mößbauer spectroscopy and can be correlated to the change in the T_cs. Furthermore, the copolymers were investigated via¹H and inverse gated (IG) ¹³C NMR spectroscopy, size exclusion chromatography (SEC), MALDI-ToF mass spectroscopy and differential scanning calorimetry (DSC). The reversible oxidation of the fc moities is demonstrated by cyclic voltammetry.