Preparation And Application Of Biomass Fiber Based Flexible Electronic Devices

The flexible electronic devices have entered the era of information technology,healthcare,and wearable intelligence due to excellent flexible and extensibility,can meet the requirement of the deformation on the human and machine.At present,flexible electronic devices still have the problems of difficult to construct the functional conductive structures and poor permeability.Fiber and textiles are the ideal materials for flexible electronic devices due to the excellent flexibility,air permeability,processability and structural flexibility.Juncus effuses(JE),being a kind of lignocellulosic fiber,possess a rich internal three-dimensional network structure,which makes them ideal for constructing fiber-based flexible electronic devices.This study leverages the unique internal structure of JE fibers to develop flexible electronic devices with Joule heating and motion sensing,triboelectric effect,and magnetoelectric effect energy harvesting functions.The main results are listed follows:By utilizing the internal network structure as the backbone,the composite multifunctional conductive network was constructed,and the good synergy between it and graphene/polypyrrole(PPy)was fully utilized to prepare a conductive JE fiber with excellent Joule thermal performance and motion sensing ability.The microstructure,conductive network distribution,and conductive properties of JE fibers loaded with different conductive functional substances were systematically investigated,and their effects and mechanisms on the Joule heating and motion sensing properties were examined.The graphene/PPy JE fibers have excellent Joule heating and motion sensing ability and can be rapidly heated up to 147.2℃and remain stable under 10 V driving.The conductive fiber exhibits good stability and sensitivity in the strain range of 10-100%and can maintain stability after 500 cycles of stretching.Therefore,the graphene/PPy JE fibers have excellent Joule thermal properties and can effectively sense and recognize common human limb movements.A contact-separated triboelectric nanogenerator(TENG)was designed to achieve stable conversion of mechanical energy to electrical energy by using the JE fiber as a friction polar material for TENG with its multi-scale microstructure and easy processing properties.The microscopic morphology and chemical composition of JE fiber and powder in different forms were investigated,and the influence of JE fiber structure on the frictional electrical properties was systematically analyzed to explore the energy harvesting and output performance of the JE-based TENG at different frequencies.The results show that the JE powder frictional electric stage has the best generation and energy harvesting performance,capable of generating 43.2 V open-circuit voltage and 1.9μA current at 5 Hz,with a maximum output power density of 79 m W/m~2 at a load resistance of 40 MΩ,and capable of energy storage through capacitors of different capacities.The magnetoelectric energy-harvesting fabric was developed by combining magnetic polyurethane with JE fibers to construct a highly-loaded magnetic network,which enabled efficient and stable energy conversion through simple motion.A systematic investigation was conducted to study the microstructure,magnetic particle content,loading method,and polymer ratio,which affect the magnetic properties of the fibers.Moreover,the relationship between different human body movement patterns and the power generation performance of the magnetic JE fabric was analyzed.The mechanism of the mechanical energy-electricity conversion of the magnetoelectric energy harvesting fabric was also explained.Results showed that the magnetic field strength of the magnetic JE fiber could reach up to 24.61 m T,and the woven magnetoelectric energy harvesting fabric could achieve an open-circuit voltage of 2 V and a short-circuit current signal of 3 m A through arm swinging.Furthermore,the magnetic JE fabric could output up to 10 m W of power when the load resistance is 500Ω,which could stably drive small electronic devices.In conclusion,this study leverages the unique internal structure of JE fibers to develop flexible electronic devices with Joule heat and motion sensing,frictional electric effect,and magnetoelectric effect energy harvesting functions.By loading different functional substances,the application of JE fibers in the field of energy harvesting and flexible sensing is broadened.The findings of this study provide new ideas for the development of fiber-based flexible electronic devices.