Metal-conducting polyaniline (PANI)-based nanocomposite materials have attracted attention in various applications due to their synergism of electrical, mechanical, and optical properties of the initial components. Herein, metal-PANI nanocomposites, including silver nanoparticle-polyaniline (AgNP-PANI), zinc oxide nanoparticle-polyaniline (ZnONP-PANI), and silver-zinc oxide nanoparticle-polyaniline (Ag–ZnONP-PANI), were prepared using the two processes. Nanocomposite-based electrode platforms were prepared by depositing AgNPs, ZnONPs, or Ag–ZnONPs on a PANI modified glass carbon electrode (GCE) in the presence of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide/N-Hydroxysuccinimide (EDC/NHS, 1:2) as coupling agents. The incorporation of AgNPs, ZnONPs, and Ag–ZnONPs onto PANI was confirmed by UV-Vis spectrophotometry, which showed five absorbance bands at 216 nm, 412 nm, 464 nm, 550 nm, and 831 nm (i.e., transition of π-π*, π-polaron band transition, polaron-π* electronic transition, and AgNPs). The FTIR characteristic signatures of the nanocomposite materials exhibited stretching arising from C–H aromatic, C–O, and C–N stretching mode for benzenoid rings, and =C–H plane bending vibration formed during protonation. The CV voltammograms of the nanocomposite materials showed a quasi-reversible behavior with increased redox current response. Notably, AgNP–PANI–GCE electrode showed the highest conductivity, which was attributed the high conductivity of silver. The increase in peak currents exhibited by the composites shows that AgNPs and ZnONPs improve the electrical properties of PANI, and they could be potential candidates for electrochemical applications.

A series of sulfonated polyaniline/derivatized polyaniline nanocomposites was chemically synthesized in the presence of anthracene and naphthalene sulfonic acids. UV-vis and FTIR results indicated the emergence of new bands at 420 and 700 nm and 1100 cm⁻¹ in their spectra, respectively, meaning the dopant/polymer intercalations involved electronic interactions between dopant/polymer sub-lattices. The electroactive composites displayed moderately fast electrode kinetics. A composite-based biosensor for hydrogen peroxide reached a steady state current of 9.2 and 5.3 µA, and when fine-tuned for diazinon detection gave % inhibitions to be 41 and 81% for the polyaniline and poly-o-methoxyaniline biosensors, respectively.

Nanoparticles are considered unique sensing material as they are small and deliver sensitivity as low as parts per billion compared to their bulk counterparts used in the conventional devices. Zinc Oxide (ZnONPs) nanoparticles are considered one of the promising sensing materials due to their high surface-to-volume ratio compared to other conventional sensing materials. They have been found useful for sensing of hydrogen gas, carbon monoxide, ammonia and ethanol. Ethanol sensing forms a platform for monitoring various processes in medical and food industries. Herein, zinc oxide nanoparticles were synthesized using Spathodea campanulata plant extract as reducing and stabilizing agent. The biosynthesized nanoparticles were used to fine tuning a glassy carbon electrode (GCE) for ethanol sensing. Ethanol sensing capability of the modified GCE electrode was gauged upon its amperometric responses to different ethanol concentrations. The high surface to volume ratio of the nanoparticles greatly enhanced peak currents of the modified electrodes leading to signal towards ethanol detection.