Temperature-induced Packaging of Ferricyanide by Help of Cationic Microgels
F. Plamper,a X. Whosoeverb
aInstitute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany bInstitute of Quantum Irregularities, The Good University, 00000 Capital, Wonderland
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 . E.g., complexes between polyelectrolytes and hexacyanoferrates provoke film formation onto the electrodes upon electrolysis . The use of branched bis-hydrophilic ionic/non-ionic polymers favor bulk aggregation instead of film formation . 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 . Finally, we discuss, how the size of microgels can be altered electrochemically .
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.
F. Plamper, Adv. Polym. Sci. 2015, 266, 125
 M. Ohyanagi, F. C. Anson, J. Phys. Chem. 1989, 93, 8377
 F. Plamper, L. Murtomäki, A. Walther, K. Kontturi, H. Tenhu, Macromolecules 2009, 42, 7254
 O. Mergel, A. Gelissen, P. Wünnemann, A. Böker, U. Simon, F. Plamper, J. Phys. Chem. C 2014, 118, 26199
 O. Mergel, P. Wünnemann, A. Böker, U. Simon, F. Plamper, Chem. Mater. 2015, 27, 7306