Raman spectroelectrochemical study of poly(N-methylaniline) at UV, blue, red, and NIR laser line excitations in solutions of different pH.

A detailed study on Raman spectroelectrochemistry of poly(N-methylaniline) (PNMA) layer deposited at a gold electrode was performed. Raman spectra were excited by four different laser wavelengths: UV line at 325 nm, a blue line at 442 nm, a red line at 633 nm, and a NIR line at 785 nm in solutions of different pH ranging from 1 to 9, and at different electrode potentials ranging from -0.5 V to 0.

Poly(N-methylaniline) vs. polyaniline: An extended pH range of polaron stability as revealed by Raman spectroelectrochemistry.

A comparative study of polyaniline (PANI) and poly(N-methylaniline) (PNMA) has been performed by means of Raman spectroelectrochemical technique at 633 nm and 785 nm laser line excitations. The excitation wavelengths used fall into a resonance with the blue colored semi- and full-oxidized forms of these conducting polymers. The dependence of Raman features on electrode potential and solution acidity was studied, and relative content of polaronic and bipolaronic states was evaluated.

Differential multiwavelength Raman study of electrochemical redox transitions of polyaniline in solutions of different acidities.

A detailed Raman spectroelectrochemical study on polyaniline has been performed with the use of different laser lines ranging from UV (325 nm) through blue (442 nm) and green (532 nm) up to the red (633 nm) for spectra excitation, and within a broad range of solution pH from 1 to 9. From the data obtained, differential Raman spectra showing spectral changes occurring by a partial electrooxidation of polyaniline from its reduced to semioxidized, and by full oxidation to the fully oxidized states, were derived and analyzed. Different spectral features, appearing in electrochemical processes, were related to structural changes occurring during a partial or full electrooxidation of this polymer, to changes in its protonation state, and to resonance enhancement at different excitation wavelengths for different redox forms.

Study of redox and protonation processes of polyaniline by the differential multiwavelength Raman spectroelectrochemistry.

Polyaniline layer has been deposited at a gold electrode and subjected to differential multiwavelength Raman spectroelectrochemical study. A broad set of laser line excitation wavelengths was used, including UV (325 nm), blue (442 nm), green (532 nm), red (633 nm), and far red (785 nm). From measurements performed, potential-difference Raman spectra, related to small-step changes of electrode potential were derived, and specific spectral and structural features were obtained and analysed.

SERS spectroelectrochemical study of electrode processes at copper hexacyanoferrate modified electrode.

Electrochemical redox processes taking place at copper hexacyanoferrate (CuHCF) modified electrode have been investigated by near-infrared laser (785nm) induced surface-enhanced Raman spectroscopy (SERS). Raman bands observed within the spectral ranges of 2200-2000cm and 500-100cm, as well as their dependence on electrode potential, have been analysed. The most characteristic Raman bands, related to triple CN bond vibrations and centered at 2187 and 2127cm were assigned to the oxidised and the reduced forms of CuHCF, respectively.

Mediated amperometry reveals different modes of yeast responses to sugars.

Menadione-mediated amperometry at carbon paste electrodes modified with various yeasts (Saccharomyces cerevisiae, Candida pulcherrima, Pichia guilliermondii and Debaryomyces hansenii) was employed to monitor redox activity inside the yeast cells induced by glucose, fructose, sucrose, maltose or galactose. Continuous measurements revealed distinct modes (transient or gradually increasing) of the current development during the first 2 to 3 min after subjection to glucose, fructose and sucrose at electrodes containing S. cerevisiae and non-Saccharomyces strains.

Chemical oxidation of aniline and N-methylaniline: a kinetic study by Raman spectroscopy.

For the first time, chemical oxidation of aniline and N-methylaniline with dichromate as oxidant has been studied by Raman spectroscopy with 785 nm laser beam excitation, and the suitability of this technique for kinetic study of this process was demonstrated. For both monomers used, a sigmoidal growth of the intensities for most prominent Raman bands was observed, showing a self-accelerating character of this reaction. Self-acceleration appears most clearly expressed for aniline, and for the low oxidant-to-monomer molar ratio used.

Raman spectroelectrochemical study of Meldola blue, adsorbed and electropolymerized at a gold electrode.

Surface-enhanced Raman spectroscopy (SERS) was used to probe the structure of adsorbed and electropolymerized Meldola blue (MB) films on roughened gold surfaces in solutions with pH 1.0 and 7.0 by using 785 nm excitation wavelength.