Journal Article

Interdigitated Electrode for Electrical Characterization of Commercial Pseudo-Binary Biodiesel–Diesel Blends

Santos, Giselle Cutrim de Oliveira, Filho, Gilberto Balby Araújo, Carvalho, Christian Diniz, Casas, Vicente Leonardo Paucar, Lopes, Alberto Jorge Oliveira, Silva, Fernando Carvalho, Andrade, Cassio Daniel Salomão Silva, Neto, João Viana da Fonseca, Alencar, Luciana Magalhães Rebelo, Sinfrônio, Francisco Sávio Mendes, Santos-Neto, Inocêncio Sanches dos, Barros, Allan Kardec

2021

Overview

Non-standard diesel blends can be harmful to the environment and human health. In this context, a simple analytical method to estimate the biodiesel mixture ratio in diesel was developed based on impedance spectroscopy (IS) associated with interdigitated sensors. In this article, four different interdigitated sensors with varied comb spacing (G) were simulated using the COMSOL Multiphysics software. Based on finite element simulations, four interdigitated electrode architectures were manufactured and evaluated. The best geometry was chosen according to theoretical data simulations, and its interdigitated electrodes were manufactured for the compositional evaluation of pseudo-binary biodiesel–diesel mixtures. According to the X-ray powder diffraction technique, the deposition of the conductive layer (Au0) over the surface of the dielectric substrate (SiO2) did not alter its phase composition. In the analysis of AFM and SEM, it was possible to observe irregular edges on the electrodes, possibly related to the manufacturing process of the thin layers and mechanical stability. Another characteristic observed in the AFM images was the height of the step of the gold layer of the sensor. Several cross sections were obtained, and the mean step value was 225.71 ± 0.0032 nm. Although there were differences in the roughness, the whole sensor had nanometric roughness. Based on the finite element method simulation performed, it can be assumed that the geometric parameters more suitable for the manufacturing of the electrode are W = 20 µm, L = 1000 µm, G = 50 µm, and N = 40 digits. The electrical characterization performed by impedance spectroscopy showed that we could differentiate between biodiesel and diesel fuels and their pseudo-binary mixtures in the low-frequency region.

• Publisher: MDPI AG,MDPI
• Subject: Biodiesel fuels / capacitive sensor / Design / Dielectric properties / Electric fields / Electrodes / Finite element analysis / interdigitated electrodes / Manufacturing / pseudo-binary biodiesel–diesel blends / Sensors