Liquid-core, piezoresistive, fully polymer-based pressure sensor

A new, resistive transducer principle, suitable for pressure sensing and related applications, is presented. The technique relies on the pinching of an electrolyte-filled, microfluidic channel by pressure-induced deformation of an elastic membrane forming a part of the channel wall (liquid-core strain gauge). The resulting change in resistance along the channel is directly related to the membrane deflection. A prototype of a fully polymer-based pressure sensor has been fabricated in silicone elastomer as a proof of principle, with a sensitivity between 60 and 90 ppm resistance change per Pa (equivalent to ∼4 Ω/Pa). The paper describes the underlying transducer principle, the device fabrication and an analytical model for designing transducer geometries suitable for a variety of applications.