Temperature-induced Packaging of Ferricyanide by Help of Cationic Microgels

Temperature-induced Packaging of Ferricyanide by Help of Cationic Microgels

Polyelectrolytes interact strongly with multiple-charged counterions, whose valency (charge) can be changed by various means. Electrochemically-addressable counterions are of scientific interest since years [1]. E.g., complexes between polyelectrolytes and hexacyanoferrates provoke film formation onto the electrodes upon electrolysis [2]. The use of branched bis-hydrophilic ionic/non-ionic polymers favor bulk aggregation instead of film formation [3]. Then, the electrochemical switching of macromolecules between the unimeric and the micellar/vesicular state could be observed. We now address thermosensitive cationic microgels and their influence on the electrochemistry of hexacyanoferrates. Hereby, we use hydrodynamic voltammetry and electrochemical impedance spectroscopy. This allowed a distinction between the electron pathways (Figure), suggesting the preferred uptake of ferricyanide into the microgel. The microgels collapse at elevated temperature, leading to an increased uptake [4]. Finally, we discuss, how the size of microgels can be altered electrochemically [5].

Simplified situation at the electrode immersed in a solution containing cationic microgels and anionic hexacyanoferrates.

Acknowledgements. The funding of the German Research Foundation (DFG) within SFB 985 (Functional Microgels and Microgel Systems) is gratefully acknowledged.

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[3] F. Plamper, L. Murtomäki, A. Walther, K. Kontturi, H. Tenhu, Macromolecules 2009, 42, 7254

[4] O. Mergel, A. Gelissen, P. Wünnemann, A. Böker, U. Simon, F. Plamper, J. Phys. Chem. C 2014, 118, 26199



[5] O. Mergel, P. Wünnemann, A. Böker, U. Simon, F. Plamper, Chem. Mater. 2015, 27, 7306