A Microfluidic Device with Embedded Capacitive Sensor for Fluid Discrimination and Characterization

This paper describes the development of a microfluidic device with embedded capacitive sensing that allows the discrimination of fluids on the basis of the dielectric permittivity. The device is fabricated in a hybrid technology, which innovatively combines PDMS (PolyDiMethylSiloxane) soft photolithography and screen printing techniques. A microchannel, realized in a PDMS layer, is placed in the fringe field of a sensing capacitor formed by electrodes screen-printed on a glass substrate. Fluids inside the microchannel affect the capacitance that is measured by a tailored electronic interface system. Experimental results are reported demonstrating the capability of the system to discriminate different fluids and estimate their dielectric permittivity.