All-Polymer Electrolytic Tilt Sensor with Conductive Poly(dimethylsiloxane) Electrodes

In this study, an all-polymer electrolytic tilt sensor with conductive and corrosion-resistant poly(dimethylsiloxane) (PDMS) electrodes was designed and its performances were characterized. A PDMS cavity in the sensor for holding an electrolyte was fabricated by soft lithography using an ultraviolet-sensitive polymer. A conductive PDMS composite ( g PDMS) with graphite powder was used for the electrode to measure the inclination angle of the electrolyte. A g PDMS composite with a graphite concentration above 40 wt % was able to function as a conductive polymer. The fabricated all-polymer tilt sensor exhibited a detectable inclination range of ±60° and showed a relatively linear output signal compared with those exhibited by conventional micromachined tilt sensors with axis asymmetrical cavities. The maximum hysteresis of the output signal was approximately 0.1 V rms when the sensor repeatedly tilted and leveled off. In addition to the fundamental characterization of the sensor, various characteristics of the all-polymer tilt sensor, such as time-dependent and electrolyte-volume-dependent variations in the output signal, were investigated in this study. While the performance of the proposed sensor was comparable to that of conventional silicon-micromachined tilt sensors, the sensor could be produced at a fraction of the cost required to fabricate the conventional sensors.