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).
Highlights
Fourier-transform infrared spectroscopy (FT-IR) evaluation of the three oil degradation parameters are of important interest in the current study given that they are used as a reference and validation method for the measurements obtained with the proposed sensor
Based on the above and considering the linear trends obtained from the different measurements of the specific samples under study, which are in the service life interval of the lubricant recommended by the manufacturer, it is possible to propose that a displacement of the localized surface plasmon resonance (LSPR) band beyond 590 nm, using the proposed sensor, will indicate that the lubricant has reached the end of its useful life
The chemical properties of lubricant oil were analyzed by FT-IR spectroscopy according to standard practice ASTM E2412 to evaluate the evolution of oxidation, nitration, and sulfation levels with mileage, as the reference and validation method for the proposed sensor, of which the results were further correlated
Summary
Among the different mechanisms of oil degradation, oxidation is the main reaction to cause the loss of properties of the lubricant, given that its base is composed of long hydrocarbon chains that are susceptible to oxidation when exposed to high temperatures [3] During this process, free radicals are generated, which are undesirable because they damage the chemical structure of the lubricant [4]. Advances were made in the detection of the interaction between molecules close to the surface of the nanoparticles through changes in the surface plasmon resonance (SPR) or LSPR, due to the high sensitivity to the refractive index of the medium surrounding the nanoparticle [12,13] These types of sensors have several advantages since they could be used for real-time sensing and the wavelength of the SPR or LSPR can be tuned for different applications, such as detectors for drugs, biomolecular interactions, gases, pH, among others [14,15,16,17,18,19,20,21]. The sensor based on the LSPR of AgNP was used to detect changes in the engine oil condition, and the response of the sensor was correlated with the chemical properties obtained by FT-IR analysis based on the standard practice ASTM E-2412 in order to compare its effectiveness
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
