Nanoscale conductivity mapping of hybrid nanoarchitectures: Ultrathin poly(o-phenylenediamine) on mesoporous manganese oxide ambigels

Todd M. McEvoy, Jeffrey W. Long, Timothy J. Smith, Keith J. Stevenson

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)

Abstract

We use conductive-probe atomic force microscopy (CP-AFM) to characterize and image hybrid electrode structures comprising mesoporous manganese oxide (MnO 2) ambigel nanoarchitectures coated with an ultrathin (<10 nm) electrodeposited layer of poly(o-phenylenediamine), PPD. Native MnO 2 ambigel films, supported on indium tin oxide (ITO) substrates, exhibit spatially uniform conductivity that correlates well with the topography of the MnO 2 film, confirming that the nanoscopic oxide network is effectively wired to the underlying ITO substrate. Following the self-limiting electrodeposition of the PPD coating onto the high-surface-area (>200 m 2 g -1) MnO 2 ambigel, the resulting hybrid structures display an ∼20-fold reduction in conductivity, as determined from CP-AFM measurements. The CP-AFM imaging studies confirm that the ultrathin, insulating PPD layer conformally and homogeneously coats the conductive nanoarchitecture. CP-AFM imaging of PPD-MnO 2 hybrid electrodes following electrochemical cycling in an aqueous acid electrolyte reveals that the ultrathin PPD coating serves as an effective barrier to the electrolyte, protecting the underlying MnO 2 nanoarchitecture from electrochemical dissolution.

Original languageEnglish
Pages (from-to)4462-4466
Number of pages5
JournalLangmuir
Volume22
Issue number10
DOIs
Publication statusPublished - 9 May 2006
Externally publishedYes

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