Study On The Preparation,Properties And Application Of Biomass Polymer Composite For Flexible And Wearable Electronic Devices

Recently,wearable electronic devices made of petroleum-based flexible stretchable polymer materials have attracted a myriad of research interest due to their potential applications for human motion monitoring,electronic skin,and intelligent robots.The widespread use of electronic devices will inevitably cause pollution to the ecological environment.As the concept of green sustainable development becomes more and more popular,the development of green and sustainable biomass materials to prepare environmentally friendly flexible electronic devices has become a research hotspot.Natutral cellulose paper is a cheap and available material with the merits of non-toxic,harmless,biodegradable,and recyclable.However,natural cellulose paper is hygroscopic and has modest mechanical properties,which limits its potential applications in paper-based electronics.Therefore,it is of great importance to seek new flexible paper-based substrates with excellent performance to prepare environmentally friendly wearable electronic devices.Currently,the majority of research work on flexible wearable devices still focuses on the optimization of a single performace,such as increasing the stretchability or improving the sensitivity.This type of sensor can only detect a single stimulus response,resulting relatively limited application scenarios,and it is hard to truly apply it in real life in the face of complex and changeable working environments.Therefore,simulating the characteristics and functions of human skin to prepare polymer materials with excellent comprehensive performance and diverse functions is of great significance to the development of wearable electronics.The main research work of this thesis is as follws:(1)Preparation of high-performance cellulose paper-based composite material and their applications in strain sensors.Cellulose paper as a flexible substrate has attracted widespread attention due to its own advantages.However,cellulose paper as a substrate material has two major shortcomings:(1)The mechanical properties of cellulose paper are poor,and it is difficult to meet the mechanical properties of most electronic devices;(2)Cellulose paper is randomly interwoven with long cellulose fibers.Its loose porous structure is highly hygroscopic,which makes cellulose paper-based electronic devices difficult to use in humid environments.Aming at the two major shortcomings of cellulose paper-based substrates,this chapter uses vegetable oil-based polybasic acids to prepare polyester vitrimer precusors,which are infiltrated into porous cellulose paper by a simple physical knife coating to prepare paper-based substrate with high mechanical performance and water resistance and use it for strain sensors.The experimental results show that this type of paper-based composite material not only has excellent mechanical properties(tensile strength up to 72 MPa,and the folding resistance is increased by more than 10 times),but also has good water resistance(it can be soaked in water for a long time without obvious shape changes).Sensing performance studies show that the strain sensor made of this type of paper-based composite material has has high sensitivity(GF=43),fsat response time,and good reliability and durability,showing prospect application in human motion monitoring.(2)Prepare polymer composites with diversified properties by simulating the characteristics and functions of the human skin,and use them to assemble multifunctional electronic skins that can detect strain,pressure and temperature.First,poly-lipoic acid composite material(PLA)was synthesized by using biomass ?-lipoic acid(LA),acrylic acid(AA),choline chloride(CCI)and ferric chloride.Then the poly-lipoic acid composite material and MXene were blended to successfully prepare an instantaneous self-healing supramolecular nanocomposite(PLA-M).The supramolecular composite with the incorporation of 4.2 wt%MXene displayed a tensile strength of 0.28 MPa with an elongation over 4000%,where the rapid self-healing of mechanical properties was achieved within 10 s.The composite material also exhibited strong adhesiveness to a broad range of inorganic and organic substrates,and it was further fabricated as a multifunctional electronic skin for the detection of strain,pressure and temperature.The novel PLA-M supramolecular composite has demonstrated great potential as multifunctional electronic skin for wearable electronics,which provides a facile and promising approach to development of various flexible electronic materials with multifunctionalities by combining MXene with supramolecular polymers.