Tuning percolation speed in layer-by-layer assembled polyaniline–nanocellulose composite films

Polyaniline of low molecular weight (ca. 10 kDa) is combined with cellulose nanofibrils (sisal, 4–5 nm average cross-sectional edge length, with surface sulphate ester groups) in an electrostatic layer-by-layer deposition process to form thin nano-composite films on tin-doped indium oxide (ITO) subs...

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Bibliographic Details
Published inJournal of solid state electrochemistry Vol. 15; no. 11-12; pp. 2675 - 2681
Main Authors Shariki, Sara, Liew, Soon Yee, Thielemans, Wim, Walsh, Darren A., Cummings, Charles Y., Rassaei, Liza, Wasbrough, Matthew J., Edler, Karen J., Bonné, Michael J., Marken, Frank
Format Journal Article
LanguageEnglish
Published Berlin/Heidelberg Springer-Verlag 01.12.2011
Subjects
Analytical Chemistry
Characterization and Evaluation of Materials
Chemistry
Chemistry and Materials Science
Condensed Matter Physics
Electrochemistry
Energy Storage
Original Paper
Physical Chemistry
Electrocatalysis
Phase propagation rate
Cellulose
PANI
Percolation
Voltammetry
Junction
Electrochromism
Polyaniline
Nanofibril
Layer-by-layer assembly
Nanocrystal
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Summary:Polyaniline of low molecular weight (ca. 10 kDa) is combined with cellulose nanofibrils (sisal, 4–5 nm average cross-sectional edge length, with surface sulphate ester groups) in an electrostatic layer-by-layer deposition process to form thin nano-composite films on tin-doped indium oxide (ITO) substrates. AFM analysis suggests a growth in thickness of ca. 4 nm per layer. Stable and strongly adhering films are formed with thickness-dependent coloration. Electrochemical measurements in aqueous H 2 SO 4 confirm the presence of two prominent redox waves consistent with polaron and bipolaron formation processes in the polyaniline–nanocellulose composite. Measurements with a polyaniline–nanocellulose film applied across an ITO junction (a 700 nm gap produced by ion beam milling) suggest a jump in electrical conductivity at ca. 0.2 V vs. SCE and a propagation rate (or percolation speed) two orders of magnitude slower compared to that observed in pure polyaniline This effect allows tuning of the propagation rate based on the nanostructure architecture. Film thickness-dependent electrocatalysis is observed for the oxidation of hydroquinone.
ISSN:1432-8488
1433-0768
DOI:10.1007/s10008-010-1261-z