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Fevzi Cebeci Postdoctoral Associate |
Prussian Blue-Based Electrochemically Responsive Films
I am currently working on the electrochemically mechano-mutable
nanocomposite polyelectrolyte multilayer (PEM) films that incorporate
Prussian Blue (PB) nanoparticles, which are inorganic iron
hexacyanoferrate orthorhombic polycrystals. The chemical formula of
crystalline structure is Fe7(CN)18(H2O)x
where 14 ≤ x ≤ 16 and polycrystalline nanoparticles are typically 5-7 nm
in size, which undergo multiple reversible oxidation states upon an
electrochemical potential application.
As the Hammond Group has previously demonstrated1-2, PB
nanoparticles and various strong and weak positively charged
polyelectolytes will be assembled in a layer-by-layer method to produce
insoluble, thin films held together by ionic crosslinks. By tuning the
polymer/iron ratio, PB particle size in the PEM films will be changed
and surface of the PB nanoparticle will be modified. By using different
polycations, such as poly(allylaminehydrochloride) (PAH), linear
polyethyleneimine (LPEI), branched polyethyleneimine (BPEI),
poly(diallyldimethyl-ammonium chloride) (PDAC), and some other
commercial polycations, the charge density in the films be varied. When
the PB in these LbL films is switched to the neutral Prussian Brown
state (when the iron atoms in the nanoparticles are completely
oxidized), the films are no longer electroneutral; hence, deconstruct
due to the electrostatic repulsion of positively charged polymer chains.1
(1) DeLongchamp, D.M. and P.T. Hammond, "High-contrast
electrochromism and controllable dissolution of assembled Prussian
blue/polymer nanocomposites." Advanced Functional Materials, 2004.
14(3): p. 224-232.
(2) DeLongchamp, D.M. and P.T. Hammond, "Multiple-color electrochromism
from layer-by-layer-assembled polyaniline/Prussian blue nanocomposite
thin films." Chemistry of Materials, 2004. 16(23): p. 4799-4805.
