Usefulness of aqueous micellar media for electrosynthesis of poly(N-phenylpyrrole). Characterization and optical properties

Poly-N-phenyl-pyrrole [poly(N-PhPy)] was electrosynthesized by anodic oxidation of N-PhPy on Pt electrode in acid aqueous micellar medium (0.1 M sodium dodecyl sulfate (SDS) + 1.93 M HClO4 in 84/16 water/butanol v/v), using cyclic voltammetry (CV), chronoamperometry and chronopotentiometry. Electroactive poly(N-PhPy) films were formed upon scanning the potential (E) between 0.0 and 1.4 V/SCE, under controlled potential (E = 0.9–1.3 V/SCE) or controlled current density (J = 0.125–2.0 mA/cm2). The poly-NPhPy films were characterized by CV, MALDI-TOF mass spectrometry, FT-IR and X-ray photoelectron spectra (XPS), and their morphology was studied by scanning electron microscopy (SEM). Their optical properties, including electronic absorption and fluorescence spectra, were also investigated. A multiple-step mechanism for the poly(N-PhPy) films formation in micellar medium, based on the MALDI-TOF, FT-IR and XPS results, was proposed.

Scheme of the proposed multiple-step mechanism of the poly(N-PhPy) film formation in acid aqueous micellar medium, showing the loss of a pyrrolyl group and the incorporation of one oxygen atom, in the case of a “modified” tetramer.Figure optionsDownload as PowerPoint slideHighlights
► Electrosynthesis of poly-N-phenyl-pyrrole [poly(N-PhPy)] by anodic oxidation of N-PhPy on Pt.
► Acid aqueous micellar medium (0.1 M sodium dodecyl sulfate, SDS).
► Formation of electroactive poly(N-PhPy) films.
► Characterization of poly(N-PhPy) films (oligomers) by MALDI-TOF, FT-IR and XPS.
► Weak red-shifts of the poly(N-PhPy) UV–Vis absorption and fluorescence spectra maximums relative to N-PhPy.