Study of poly(o-Ethoxyaniline) interactions with herbicides and evaluation of conductive polymer potential used in electrochemical sensors

Abstract

Foram investigadas as interações entre os pesticidas atrazina, imazaquin, metribuzin e paraquat com o polímero condutor poli-(o-etoxianilina)-POEA, utilizando-se as técnicas de microscopia de força atômica (AFM), espectrofotometria de ultravioleta visível (UV-Vis) e espectroscopia de impedância eletroquímica. Os estudos de microscopia de força atômica em filmes automontados mostraram um aumento na rugosidade do filme polimérico, quando exposto aos pesticidas atrazina, imazaquin e metribuzin e uma diminuição na rugosidade do filme polimérico exposto ao pesticida paraquat. Isso evidencia a existência de interação química, provavelmente, ligação iônica entre o nitrogênio presente na POEA e os grupos presentes nos pesticidas estudados. Os estudos de ultravioleta visível mostraram uma maior interação entre a POEA e o pesticida imazaquin. Por meio de medidas elétricas realizadas (espectroscopia de impedância eletroquímica) com um sensor formado por filme de POEA, foi possível distinguir e determinar o limite de detecção dos pesticidas em solução aquosa, o que corrobora com os estudos por AFM e UV-Vis.Interactions of four aromatic nitrogen-heterocyclic herbicides (atrazine, imazaquin, metribuzin and paraquat) with the conductive polymer poly(o-ethoxyaniline)-POEA, were studied with atomic force microscopy (AFM), UV-visible spectrophotometry (UV-Vis) and electrochemical impedance spectroscopy. AFM profiles of self-assembled (SA) films of POEA revealed that the polymer surface became rougher (on the nanoscale) when exposed to atrazine, imazaquin and metribuzin, but slightly smoother in contact with paraquat. This suggested that specific chemical interactions, possibly electroscopic, have occurred between nitrogen atoms in the polymer chain and the dissimilar groups in the various herbicide molecules, during adsorption of the latter onto the film. The UV-Vis analyses indicated a stronger interaction of POEA in solution with imazaquin, that has a special importance for the intended application. Sensors produced by coating microelectrodes with SA films of POEA were used to perform impedance spectroscopy in aqueous solutions of each herbicide. With the resulting data, it was possible to distinguish and set detection limits for each herbicide in water, corroborating AFM and UV-Vis results.

TEM, XRD and AFM study of poly(o-ethoxyaniline) films: new evidence for the formation of conducting islands

“…This has allowed films to be obtained with various substituted polyanilines, e.g. poly(omethoxyaniline) (POMA) [5,6] and poly(o-ethoxyaniline) (POEA) [7,8]. The degree of protonation and the conductivity vary within the PANI class, which is attributed to differences in conformation of the polymer chains and packing in a film.…”

Corrosion Protection of Graphene-Modified Zinc-Rich Epoxy Coatings in Dilute NaCl Solution

“…Figure a showed UV–vis results of PANI and PANI-G hybrid dispersed in THF. The peaks of PANI located at 313 and 604 nm corresponded to the π–π* transition of the benzene unit and the n−π* transition of benzenoid to quinoid, respectively . With regard to PANI-G hybrid, the peak located at 604 nm shifted to 597 nm, confirming the π–π interaction between PANI molecules and graphene nanosheets.…”

Investigating surface and wettability properties of Na2Ti3O7/Na2Ti6O13/PVA composites

“…Atomic Force Microscopy (AFM) has found widespread application in the assessment of conductive polymers, offering valuable insights into thin film structure, surface morphology, nanostructure, polymeric chain arrangement, porosity, specific chemical interaction strengths, roughness, and electrical charge distribution [19][20][21]. This study's primary objective was to investigate the impact of introducing titanate powders, both with and without heat treatment, into the PVA matrix.…”