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Thermo‐Switchable Charge Transport and Electrocatalysis Using Metal‐Ion‐Modified pNIPAM‐Functionalized Electrodes
Author(s) -
Riskin Michael,
TelVered Ran,
Willner Itamar
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200900268
Subject(s) - materials science , nanoclusters , polymer , electron transfer , metal ions in aqueous solution , electrode , metal , chemical engineering , ion , polymer chemistry , lower critical solution temperature , poly(n isopropylacrylamide) , photochemistry , nanotechnology , chemistry , copolymer , organic chemistry , composite material , engineering , metallurgy
Metal ions (Ag + , Cu 2+ , Hg 2+ ) are incorporated into an electropolymerized, poly( N ‐isopropyl acrylamide), pNIPAM, thermosensitive polymer associated with an electrode using the “breathing‐in” method. The ion‐functionalized pNIPAM matrices reveal ion‐dependent gel‐to‐solid phase‐transition temperatures (28 ± 1 °C, 25 ± 1 °C, 40 ± 1 °C for the Ag + , Cu 2+ , and Hg 2+ ‐modified pNIPAM, respectively). Furthermore, the ion‐functionalized polymers exhibit quasi‐reversible redox properties, and the ions are reduced to the respective Ag 0 , Cu 0 , and Hg 0 nanocluster‐modified polymers. The metal‐nanocluster‐functionalized pNIPAM matrices enhance the electron transfer (they exhibit lower electron‐transfer resistances) in the compacted states. The electron‐transfer resistances of the metal‐nanocluster‐modified pNIPAM can be cycled between low and high values by temperature‐induced switching of the polymer between its contracted solid and expanded gel states, respectively. The enhanced electron‐transfer properties of the metal nanocluster‐functionalized polymer are attributed to the contacting of the metal nanoclusters in the contracted state of the polymers. This temperature‐switchable electron transfer across a Ag 0 ‐modified pNIPAM was implemented to design a thermo‐switchable electrocatalytic process (the temperature‐switchable electrocatalyzed reduction of H 2 O 2 by Ag 0 ‐pNIPAM).