Signal Output of Triboelectric Nanogenerator at Oil-Water-Solid Multiphase Interfaces and its Application for Dual-Signal Chemical Sensing

Abstract

A liquid-solid contact triboelectric nanogenerator (TENG) based on poly(tetrafluoroethylene) (PTFE) film, a copper electrode, and a glass substrate for harvesting energy in oil/water multiphases is reported. There are two distinctive signals being generated, one is from the contact electrification and electrostatic induction between the liquid (water/oil) and the PTFE film (V_TENG and I_TENG ); and the other is from the electrostatic induction in the copper electrode by the oil/water interfacial charges (ΔV_interface and I_interface ), which is generated only when the liquid-solid contact TENG is inserted across the oil/water interface. The two signals show interesting opposite changing trends that the V_TENG and I_TENG decrease while the oil/water interfacial signals of ΔV_interface and I_interface increase after coating a layer of polydopamine on the surfaces of PTFE and glass via self-polymerization. As an application of the observed phenomena, both the values of I_TENG and I_interface have a good linear relationship versus the natural logarithm of the concentration of the dopamine. Based on this, the first self-powered dual-signal detection of dopamine using TENG is demonstrated.

Keywords: chemical sensing; dopamine; interfacial charges; oil/water interface; triboelectric nanogenerators.