Research On Self-healing Flexible Electronic Devices Based On Liquid Metal/polymer Composites

With the rapid development of science and technology and the continuous progress of Internet of Things technology,the modern society has fully entered the information age.Traditional electronic devices are not easy to bend due to their excessive mechanical strength,which cannot meet the demand for device flexibility in the coming era of AI.Therefore,flexible electronics have received great attention.However,under mechanical stimuli such as stretching,internal cracks will inevitably occur in flexible devices,resulting in the degradation of device performance and shortening its service life.Hence,it is urgent to develop an effective method that can prolong the service life of the device.Inspired by the self-healing behavior of natural organisms after injury,the concept of self-healing was introduced into the field of flexible electronic devices,in order to achieve the repair of damaged flexible electronic devices and extend the durability of the devices.At present,self-healing flexible electronic devices are usually obtained by compounding self-healing polymers with conductive fillers.Most of the conductive fillers used are nanomaterials such as carbon,silver,and copper.However,these materials usually have the disadvantages of complicated preparation method,high cost,and the separation of fi llers from each other causing short working life when stretching or compressing the device.Based on this,we designed and synthesized two self-healing polymers based on multiple hydrogen bonds,and composited them with the synthesized room temperature liquid metal(LM)to develop self-healing flexible electronic devices.Benefiting from the excellent mechanical properties and self-healing properties of polymers,the high conductivity and fluidity of LM,the prepared self-healing flexible electronic devices not only have good device properties(wave absorbing properties,sensing properties,etc.),but also can restore the initial structure and performance in time after damaged,greatly prolonging the service life of the device,which shows great application potential in the field of flexible electronic devices.The specific work of the paper is as follows:(1)A self-healing polyacrylate(PMBA)was prepared based on free radical polymerization,and its structure,mechanical properties and self-healing properties were tested comprehensively,which proved the successful preparation of target product.The damaged PMBA material was placed at 90 oC for 30 h,and its structure and performance could achieve more than 90% repair.In addition,the material had excellent self-adhesion,enabling strong adhesion to a variety of substrates,which is beneficial to its application in flexible electronic devices.Subsequently,PMBA was compounded with carbon nanotubes(CNTs)and LM by a blending method to prepare a self-healing composite material and applied to wave-absorbing functional devices and flexible sensors.Both of them not only dispiay good sensing performance or wave-absorbing performance,but also show excellent self-healing ability.(2)Design and synthesis of polyacrylic acid-sodium alginate(PAA-SA)hydrogels based on the self-healing mechanism of dynamic hydrogen bonds.The obtained polymer exhibited good self-healing properties and mechanical properties.Subsequently,low-toxicity LM was composited with the synthesized hydrogel matrix as a conductive filler,and then a flexible conductive self-healing composite(PASL)with tunable conductivity was successfully prepared by utilizing its excellent conductivity and fluidity.Finally,the composite system was used to develop self-healing flexible sensors with multiple sensing capabilities and flexible wireless charging devices.