Fabrication and characterization of a titanium dioxide nanosensor for engine oil applications

• Main Author: Uon, Leapheng
• Format: text
• Language: English
• Published: Animo Repository 2019
• Subjects: Titanium dioxide; Nanotechnology; Detectors; Mechanical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/7034
• Institution: De La Salle University

This study aims to synthesize and characterize titanium dioxide nanomaterials via Horizontal Vapor Phase Growth (HVPG) Technique toward making a sensor for detecting engine oil degradation. In this work, the ramp rate was set at 10℃/min with the variation of the growth temperature at 1000℃, 1100℃, and 1200℃ and baking time at 4hrs, 6hrs, and 8hrs. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) were used for analyzing surface morphology and topology and determining the chemical composition, respectively. SEM results showed that various sizes of titanium dioxide nanoparticles were found on the substrate surface in Zone B and Zone C at the different varied growth temperature and baking time. Moreover, EDX results revealed that all of the grown nanoparticles at the varied growth mechanisms had the correct atomic ratio of titanium to oxygen. Furthermore, JMP ANOVA software was utilized to perform the statistical analysis of the grown TiO2 nanoparticle diameters in Zone B and Zone C including studying the effect of the varied growth mechanisms on TiO2 nanoparticles diameter via Graph Builder and expressing the predicted diameter equation in function of growth temperature and baking time and minimizing the nanoparticle diameters thru Fit Model. Results showed that increasing the baking temperature and time led to decrease the nanoparticle diameters. And also, the prediction expression can be utilized to predict the diameter by knowing the specific temperature and baking time within the range of the varied growth mechanisms. Based on the minimized results of both Zone B and Zone C, the best sample was obtained at 1200℃ and 8hrs the diameter of 107.1568nm. However, at the best growth mechanisms, the smallest diameter of the nanoparticles was obtained in Zone B utilized for AFM testing, mechanical properties testing, and sensor testing. Additionally, AFM was used to identify the surface roughness of the grown nanoparticles at the best growth mechanisms. Two scanning spots proceeded during AFM testing. Results presented that different scanning spots of the said nanomaterials had various average surface roughness with scanning spot A of 7.138 nm and scanning spot B of 13.405nm. In addition, UTM test and scratch test were performed to determine the force needed to crack the tubes in the purpose of comparing the stress of the tubes with and without nanomaterials and get the scratched force applied on the glass substrate in the aim of computing the stress of the grown nanomaterials. Results revealed that the stress of the grown nanomaterials was approximately obtained via the said techniques. The stress of the TiO2 nanoparticles obtained from UTM Test (𝜎𝑈𝑇𝑀) was 0.531𝑀𝑃𝑎. On the other hand, the stress of the grown nanomaterial computed by Scratch Test (𝜎𝑆𝑇) was 1.45 𝑀𝑃𝑎. Lastly, the grown nanoparticles on the glass substrate at the best growth temperature and baking time were selected to fabricate a senor for engine oil detection due to its high capability of acidic sensing. Two electrodes concept was used as a technique for sensor testing. The grown TiO2 nanoparticles were served as a working electrode while the polypyrrole conducting polymer was utilized as a reference electrode. The voltage changes produced between two electrodes were investigated when testing with the fresh oil and used oil. Results showed that voltage reading was changed in term of testing different type of engine oil. The voltage was decreased once proceeding with used oil testing. For fresh oil, the voltage reading was in rage from 478.2 mV to 498.2 mV while it was changed from 444.3mV to 465.8 mV for used oil.