Experimental Characterization of Chemical Properties of Engine Oil Using Localized Surface Plasmon Resonance Sensing

Abstract

The chemical properties of engine oil are part of the main parameters to evaluate its condition since oxidation starts chemical reactions that alter its operating conditions. In this work, the chemical properties of engine oil were analyzed based on the standard ASTM E2412 by FT-IR spectroscopy to evaluate the lubricating oil condition. Furthermore, a sensor based on the position of the localized surface plasmon resonance (LSPR) band of silver nanoparticles (AgNP), synthesized by the laser-assisted photoreduction method, was developed. This plasmonic sensor can detect changes in the permittivity of the oil, caused by the modification of the chemical properties of the lubricant. The response of the sensor during the study of degraded oil resulted in a notorious displacement to higher wavelengths of the LSPR band as mileage increases. The results of FT-IR analysis were correlated with the measurements of the proposed sensor presenting linear trends with good correlation (R2 > 0.9491).