Predictively designing a linear solid–liquid triboelectric nanogenerator for underwater tactile sensing

A conventional "design-and-then-test" methodology is employed for the design of a solid-liquid triboelectric nanogenerator (SL-TENG)-based sensor. The problem, however, is that the output is nonlinear with unknown sensitivity before it has been tested. To address this problem, predictively designing an SL-TENG sensor with linear output for underwater application is presented. First, an equation relating the sensor output to the contact length and input pressure was defined under the linear output requirement. Afterwards, the relationship between the signal output and the contact length was derived and the relationship between elastomer deformation and input pressure was established, as well as the dimensional parameters of the flexible elastomer. With the determined dimensional parameters, a sensor was fabricated and the design method was experimentally verified. It was found that a linear sensor with predictive sensitivity can be achieved with this method. To demonstrate the accuracy of this method, a sensor with a linear range of 0-270 kPa, sensitivity of 0.035 mV kPa^-1, and the ability to work stably underwater at depths of up to 100 m was designed and experimentally demonstrated.