Real time oil control by surface plasmon resonance transduction methodology

The present work focuses on the development of a Surface Plasmon Resonance (SPR) sensor transducer able to measure lubricant degradation in real time. Preliminary, several simulations were performed, by means of a commercial software (Film Wizard), in order to optimize for the specific application the sensor transducers in term of the proper choice and combination of metal layers material and thickness. In order to realize the sensing transducers, metal thin films were deposited onto SF10 glass slabs by e-beam evaporation. 4 sensing devices have been realized, calibrated and tested. They have been used to acquire the experimental reflectance curves of a new (0 km) and partially used synthetic motor oil (5700 km). Measurements proved that alteration of lubricants, which flow in the SPR sensing device, modifies the signal, which reaches the detector. Therefore, the system can be used to observe in real time oil degradation by the measurement of its optical properties, following the variation in surface plasmon resonance curves. Experimental results showed that all sensors provide good responses, variable within the range of 1%.