Utilization of commodity thermoplastic polyethylene (PE) by enhanced sensing performance with liquid phase electrolyte for a flexible and transparent triboelectric tactile sensor

Abstract

To promote the sustainable development of single-used polyethylene (PE) commodity plastic for long-lasting use in advanced electronic devices, this work presented a successful strategy for converting PE plastic bags, which usually end up in landfills, into specifically flexible and transparent triboelectric tactile sensors (TES). In order to enhance the electrical output to meet the practical application, liquid phase electrolytes (LPEs) were introduced between double sides of thin PE layers. LPE utilization had significant influence on the output signal, resulting in an effective response to physical contact with the human hand. The effect of LPE types, i.e., acids, salts and solvent as well as concentration, on output signal was studied and clarified. The scientific working mechanism for PE/LPE TES was described based on the coupling behavior between contact electrification, electrostatic induction and ion conduction within the electric double layer. The PE/LPE TES showed the optimized signal response of Voc ~1.6 V, Isc ~673 nA and 450 W/cm2, enabled by tunable LPE types and concentrations, thus providing a hundred times more than that of pristine PE. By integrating PE/LPE TES with a signal-processing circuit, wireless application of the complete tactile sensing system has been developed further to make contact with and control home appliances such as a light bulb and an electric fan. Its flexibility and transparency has great potential adaptation for the active tactile system that can be attached to different wearable devices, textiles, or home interior decoration. This work demonstrates a facile strategy for promoting PE plastic as a high value-added electronic product that has the potential to pave the way for development in large-scale industry, and help in treating used plastic in the future. It also has the opportunity to obtain a tactile sensor that is affordable and cost-effective in making a valuable contribution in the global sensor market, thus ensuring sustainable development in both social and economic terms. © 2020 Elsevier B.V.