Experimental Optical Characterization and Polymeric Layouts of Gold PDMS Nanocomposite Sensor for Liquid Detection

We present a new concept of liquid sensing based on gold nanocomposite material showing enhancement of optical radiation and coupling. In particular, we experimentally characterize the optical transmittivity response of a millimeter pillar-type sensor made of gold micro/nanoparticles in PDMS material. The choice of the millimeter pillar-type layout is studied in order to collect better the light in a multimode receiver optical fiber. After a first three-dimensional (3D) finite-element method (FEM) modeling which analyzes the physical aspects of the proposed sensor, we experimentally characterize the PDMS/PDMS-Au pillar-type layout, and we measure the variation of the transmittivity response comparing different liquids, such as ethanol and oil, placed on the PDMS-Au sensor. Concerning the reusable process of the sensor, we study the dynamics of the sensing by measuring the transmittivity response during the time by applying ethanol as target liquid. Finally, we propose an implementation of the proposed sensor in robotics finger.