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

Autor: Mažeikienė R; Department of Organic Chemistry, Center for Physical Sciences and Technology (FTMC), Sauletekio av. 3, LT-10257 Vilnius, Lithuania., Niaura G; Department of Organic Chemistry, Center for Physical Sciences and Technology (FTMC), Sauletekio av. 3, LT-10257 Vilnius, Lithuania., Malinauskas A; Department of Organic Chemistry, Center for Physical Sciences and Technology (FTMC), Sauletekio av. 3, LT-10257 Vilnius, Lithuania. Electronic address: albertas.malinauskas@ftmc.lt.
Jazyk: angličtina
Zdroj: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy [Spectrochim Acta A Mol Biomol Spectrosc] 2022 Jun 05; Vol. 274, pp. 121109. Date of Electronic Publication: 2022 Mar 09.
DOI: 10.1016/j.saa.2022.121109
Abstrakt: 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 0.8 V. UV excitation reveals features characteristic for the reduced form of PNMA, even within the electrochemical potential range where oxidized forms of this polymer prevail. At a blue laser excitation, again, features of the reduced form are revealed, along with indications on the appearance of some kind of intermediate redox state within a definite potential window. Both red and NIR laser line excitations result in rich Raman features, disclosing all major redox forms as well as their interconversions by changing of electrode potential. The presence of polaronic form of PNMA even in pH-neutral and alkaline solutions has been disclosed. A detailed analysis of Raman vibrational bands is presented for different excitation wavelengths, different electrode potentials, and different solution acidities.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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