10.1021/acsami.6b11181.s001
Govinda Ghimire
Govinda
Ghimire
Herman Coceancigh
Herman
Coceancigh
Yi Yi
Yi
Yi
Takashi Ito
Takashi
Ito
Electrochemical
Characterization and Catalytic Application of Gold-Supported Ferrocene-Containing
Diblock Copolymer Thin Films in Ethanol Solution
American Chemical Society
2016
methyl vinyl ketone
0.1 M tetrabutylammonium hexafluorophosphate
ethyl 2- oxocyclopentanecarboxylate
E 2OC
surface-confined redox species
Michael addition reaction
PS
PAEFc microdomains
Atomic force microscopy images
MeCN solution
EtOH solution
f PAEFc
Gold-Supported Ferrocene-Containing Diblock Copolymer
electron propagation efficiency
0.1 M ethanolic sodium hexafluorophosphate
PAEFc volume fractions
PAEFc films
2016-12-26 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Electrochemical_Characterization_and_Catalytic_Application_of_Gold-Supported_Ferrocene-Containing_Diblock_Copolymer_Thin_Films_in_Ethanol_Solution/4531766
This
paper reports the electrochemical behavior and catalytic property
of electrode-supported thin films of polystyrene-<i>block</i>-poly(2-(acryloyloxy)ethyl ferrocenecarboxylate) (PS-<i>b</i>-PAEFc) in an ethanol (EtOH) solution. The electrochemical properties
of PS-<i>b</i>-PAEFc films with different PAEFc volume fractions
(<i>f</i><sub>PAEFc</sub> = 0.47, 0.30, and 0.17) in 0.1
M ethanolic sodium hexafluorophosphate (NaPF<sub>6</sub>) were compared with those in an acetonitrile
(MeCN) solution of 0.1 M tetrabutylammonium hexafluorophosphate. Pristine
PS-<i>b</i>-PAEFc films did not afford significant faradaic
currents in the EtOH solution because EtOH is a nonsolvent for both
PS and PAEFc. However, the films could be rendered redox-active in
the EtOH solution by applying potentials in the MeCN solution to induce
the redox-associated incorporation of the supporting electrolytes
into the films. Atomic force microscopy images verified the stability
of PAEFc microdomains upon electrochemical measurements in these solutions.
Cyclic voltammograms measured in the EtOH solution for PS-<i>b</i>-PAEFc with the larger <i>f</i><sub>PAEFc</sub> were diffusion-controlled regardless of ellipsometric film thickness
(23–152 nm) at relatively slow scan rates, in contrast to those
in the MeCN solution that were controlled by surface-confined redox
species. The electron propagation efficiency in the EtOH solution
was significantly lower than that in the MeCN solution because of
the poorer swelling of the films, which limited the migration of counterions
and the collisional motions of the ferrocene moieties. PS-<i>b</i>-PAEFc films were applied as electrochemically responsive
heterogeneous catalysts based on the ferrocenium moieties for Michael
addition reaction between methyl vinyl ketone and ethyl 2-oxocyclopentanecarboxylate
(E2OC) in 0.1 M NaPF<sub>6</sub>/EtOH. The catalytic activities of
thin films were similar regardless of <i>f</i><sub>PAEFc</sub>, suggesting that the catalytic reaction took place for the reactants
that could penetrate through the film and reach PAEFc microdomains
communicable with the underlying electrode. Interestingly, the permeability
of PS-<i>b</i>-PAEFc films provided a means to control the
reaction selectivity, as suggested by negligible reaction of E2OC
with <i>trans</i>-4-phenyl-3-buten-2-one.