On the nature of influence of polyelectrolyte molecular weight on aniline electropolymerization

Abstract

Electrodeposition of polyaniline (PANI) complexes with a polymeric sulfonic acid of variable molecular weight has been studied with the purpose to explain specific features of aniline electropolymerization in the presence of polyelectrolytes. Poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) was taken as a model polyelectrolyte due to the ease of varying its molecular weight during polymerization of the monomer. Depending on the polyacid molecular weight, crucial changes in the shape of charge-and potential-time dependences and cyclic voltammograms have been observed during potentiostatic, galvanostatic, and cyclic voltammetry syntheses of PANI, respectively. The results are considered in terms of the influence of molecular weight on proton condensation ability of the polyacid and, therefore, on the degree of aniline protonation and its local concentration in the vicinity of polyacid macromolecule. The PANI films obtained are characterized by cyclic voltammetry and UV-vis and Raman spectroelectrochemistry, and the influence of the polyacid molecular weight on these properties is discussed.

Electrochemically-Obtained Polysulfonic-Acids Doped Polyaniline Films—A Comparative Study by Electrochemical, Microgravimetric and XPS Methods

“…Furthermore, electrochemical and/or chemical synthesis of PANI was studied in the presence of polysulfonic acids, e.g., polystyrenesulfonic (PSSA) or poly(2-acrylamido-2-methyl-1-propanesulfonic) (PAMPSA) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. In the recent years a series of papers [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ] was devoted to the properties of PANI obtained in the presence of two poly(amidosulfonic acids) that are identical in their chemical composition but differ in the rigidity of their backbone-poly-(4,4′-(2,2′-disulfonic acid)-diphenylene-tere-phthalamide) (t-PASA, rigid backbone) and poly-(4,4′-(2,2′-disulfonic acid)-diphenylene-iso-phthalamide) (i-PASA, semi-rigid backbone) ( Scheme 1 ). On the basis of comparison of electrochemical and spectroelectrochemical properties of these interpolymer PANI films, it was supposed that flexible-chain polyacids can adapt its structure to the rigid conjugated macromolecule of emeraldine form of PANI.…”

Spectroelectrochemistry of Electroactive Polymer Composite Materials

“…During investigations of the influence of PAMPSA molecular weight on the spectroelectrochemical properties of PANI-PAMPSA composite films, significant differences were detected [ 150 ]. As the molecular weight of PAMPSA was decreasing, the hypsochromic shift of PANI film absorption with increasing potential decreased and the appropriate absorption bands became less defined.…”