Fabrication And Application Of Flexible Triboelectric Nanogenerators Based On PTFE Polymer Film

The shortage of traditional fossil energy has caused widespread concern in today's society,and it has been a common concern of all countries in the world to find and develop sustainable and renewable new energy sources.As a kind of renewable energy,mechanical energy is abundantly available in our daily surroundings,therefore converting mechanical energy in the environment into electricity is considered to be a promising renewable energy conversion technology.Triboelectric nanogenerators(TENGs)is a novel energy conversion approach,which is based on triboelectric friction and electric induction for effectively converting mechanical energy from ambient sources into electric energy effectively.In TENG,the contact of two materials with different electron-attracting abilities will yield surface charge transfer.The periodic contact and separation of the oppositely charged surfaces could drive electron flow through external loads and generate electric outputs.Although TENGs have been developed rapidly in energy collection and self-powerd personal electronics in recent years,the output performance of TENGs needs to be further improved.In this paper,we fabricated some TENGs with different structures and working modes based on the polytetrafiuoroethylene(PTFE),Al foil and Cu foil,and also investigated the output performance and application.The main research and results are discribed as follows:(1)Fabrication of porous PTFE films and its application in TENG.The sponge-like porous PTFE polymer films were fabricated via a facile approach by using deionized(DI)water as the soft template,and a flexible single-electrode TENG(S-TENG)based on porous PTFE thin films was developed.PTFE thin films with different porosities were prepared to investigate the porosity dependency of the output performance.The results showed that the optimum porosity of PTFE thin film was achieved with the 50% DI water volume fraction,and the open circuit voltage could reach 5.1 V.The porous PTFE film could increase the output performance of the TENG under the same oscillation.The fabricated TENG can harvest mechanical energy from human motions,and the generated electric energycould instantaneously power 5 light emitting diodes(LEDs).This work provides important theoretical support and experimental basis for enhancing the output performance of TENG and developing self-powered personal electronics.(2)Fabrication and application of air flow-driven TENG.An air flow-driven TENG was developed by converting mechanical energy of human respiration into electric output signals for self-powered real-time respiratory monitoring.The operation of the TENG is based on the air flow-driven vibration of a flexible nanostructured PTFE thin film in an acrylic tube.This TENG can generate corresponding real-time electric signals when operated by air flow energy of different breathing states of human.It was found that this TENG-based breath monitoring system can provided a quantitative measure of the breathing behavior without any additional power.Based on this TENG,we further developed an intelligent wireless respiratory monitoring and alert system.When a person stop breathing in 5 s,this system can wirelessly trigger an alarm or dial a cell phone to provide timely alerts.This research offers a promising solution for developing self-powered real-time respiratory monitoring devices.