A series of styrenic triarylamines bearing electron-withdrawing or electron-donating substituents were synthesized and readily polymerized by nitroxide-mediated polymerization (NMP). The utility of the homopolymers as macroinitiators for the preparation of defined block copolymers is demonstrated. All redox-active polymers were characterized in detail by NMR, MS, and SEC measurements; in addition, their electrochemical properties were studied. The homopolymers undergo reversible oxidation, whereby the redox potential is modulated by the substitution pattern. In the case of the copolymers, the sequential oxidation of the individual blocks is observed and corroborated by (spectro)electrochemical measurements. The ratio of transferred charges per redox-active block agreed with the stoichiometric composition, as readily quantified by the semi-integral analysis of the electrochemical data. In addition, redox-titration experiments revealed effective electron transfer between the redox-active polymers following the order of their redox potentials. These results demonstrate the potential to achieve directional charge transfer in hierarchically defined block copolymers.
Discussion(0)
No comments yet. Be the first to comment.