Chemical sensors based on N-substituted polyaniline derivatives: reactivity and adsorption studies via electronic structure calculations

Abstract

Conjugated organic polymers represent an important class of materials for varied technological applications including in active layers of chemical sensors. In this context, polyaniline (PANI) derivatives are promising candidates, mainly due to their high chemical stability, good processability, versatility of synthesis, polymerization, and doping, as well as relative low cost. In this study, electronic structure calculations were carried out for varied N-substituted PANI derivatives in order to investigate the potential sensory properties of these materials. The opto-electronic properties of nine distinct compounds were evaluated and discussed in terms of the employed substituents. Preliminary reactivity studies were performed in order to identify adsorption centers on the oligomer structures via condensed-to-atoms Fukui indexes (CAFI). Finally, adsorption studies were carried out for selected derivatives considering five distinct gaseous analytes. The influence of the analytes on the oligomer properties were investigated via the evaluation of average binding energies and changes on the structural features, optical absorption spectra, frontier orbitals distribution, and total density of states in relation to the isolated oligomers. The obtained results indicate the derivatives PANI-NO and PANI-CH as promising materials for the development of improved chemical sensors.

Acetylated cashew gum-based nanoparticles for the incorporation of alkaloid epiisopiloturine

“…Such indexes describe how the electronic populations of the atoms change after the releasing/withdrawing of electrons in/from a given system, allowing to identify molecular sites that are prone to interact with nucleophiles (f + ) or electrophiles (f − ) [31]. In particular, these descriptors have been successfully employed in the study of polymers [[32], [33], [34], [35]] and molecules reactivity [11,27,31,36,37]. The simulations were carried out in vacuo and without temperature effects using the same DFT/B3LYP/6-31G approach employed in the optimizations.…”

“…The simulations were carried out in vacuo and without temperature effects using the same DFT/B3LYP/6-31G approach employed in the optimizations. Hirshfeld partition charge model was employed to estimate the electronic populations to avoid negative CAFIs [ [31], [32], [33], [34], [35]].…”

Polypyrrole derivatives for detection of toxic gases: A theoretical study

“…Besides presenting unique properties that allow their use in varied technological applications, polymeric materials also present reasonable chemical stability, ease of synthesis and low relative costs. In addition, a number of functionalizations can be made, allowing a wide range of optoelectronic responses for a variety of applications, 11 including as active layers of chemical sensors 12–14 …”

“…Previous works conducted by our group have shown the relevance of preliminary studies of the local reactivities to identify promising materials/sites for adsorption analysis 12–14 . In particular, density functional theory (DFT) based calculations and fully atomistic reactive molecular dynamics (FARMD) simulations have shown that the evaluation of the local reactivities and electrostatic potentials allows the identification of effective adsorption centers on the polymer structures 13 …”

Electropolymerization of aniline monomer and effects of synthesis conditions on the characteristics of synthesized polyaniline thin films

“…Therefore, Pani can be used as an electrode material 8,9 , corrosion protection of metals 10,11 , in the manufacture of secondary batteries 12 , in microelectronics 13 and as an electrochromic material [14][15][16] . Future high-tech applications in the domain of chemical sensors have also been proposed [17][18][19] . Pani can be prepared by various techniques, namely electrodeposition 20,21 , template synthesis 22,23 , seeding 24 , and interfacial polymerization 25 .…”