Mirco-structure Design And Property Research For TPU Flexible Strain Sensor Through Modification Of Graphene Synergy With Polyaniline

Flexible strain sensors have wide application potential in biomedicine,artificial intelligence and wearable device et al,due to the wonderful flexibility,excellent malleability and easy workability.However,there are some challenges in fabricating the flexible strain sensor with high sensitivity,long durability and quick responsiveness.Therefore,it’s great significant to promote the development of flexible electronic industry by manufacturing the flexible strain sensor with remarkable performance.In this paper,the mechanical property and strain response ability of strain sensors based on the substrate material of flexible thermoplastic polyurethane（TPU）has been enhanced by building micro-structure,as well as the electrical property of it has been improved by loading suitable conductive fillers.Finally,the three kinds of stable flexible strain sensors with brilliant performance have been fabricated by the process optimization.The main research contents and results are as follow:1)Study on preparation and performance of TPU fabric sensor based on modification of polyaniline（PANI）and graphene（Gr）synergism.The Gr and hydrochloric acid（HCl）-doping PANI as conductive filler were loaded on the elastic spandex fabric by ultrasonic impregnation and in-situ polymerization to fabricate the Gr/fabric,PANI/fabric and Gr/PANI/fabric（GPW）flexible strain sensors,respectively.And the structure and sensing performance of the sensors have been systematically studied.The result indicates that the excellent and stable GPW flexible strain sensor was obtained under synergy between PANI with 1.5 M HCl-doping and Gr with 0.5mg/ml.The sensitivity of GPW sensor is 15.96 at 50%strain,the response time is 350ms,the strain range is 0～100%,and the durability shows outstanding after cycle stretch 1000 times.Besides,the GPW sensor can accurately detects the human physical behavior after assembling,which shows the great potential in wearable device.2)Study on preparation and performance of electrospinning SiO₂-TPU fibrous film sensor based on synergy modification of Gr and PANI.The SiO₂-TPU（ST）fibrous films with micro-nano structure were fabricated by electrospinning technology,then the Gr/ST、PANI/ST and Gr-PANI/ST（GPST）flexible strain sensors were fabricated by employing ultrasonic impregnation and in-situ polymerization to load Gr and PANI on the ST.The effect of SiO₂ doping amount,Gr concentration and HCl doping concentration for performance of sensor were systematically investigated.The results show that the poriness of the fibrous film can be increased after SiO₂ doping and the imperfection of poor conductive of single filler can be solved by the synergy between PANI and Gr.The GPST flexible strain sensor possesses the outstanding performance which are that the wide detect range is 5～500%,the sensitivity is 201 at400%strain,the response time is 500 ms and the durability is great at 1000 times cycle stretch.Finally,this flexible strain sensor can accurately monitor and reflect the variation of body motion.3)Study on preparation and performance of high efficiency electrospinning fiber film sensor with suface micro-structure of the TPU textile by hot-press-transfer printing（HPTP）method.The flexible stress sensors with double micro-structures are fabricated by cooperating electrospinning technology with HPTP.The conductive fiber films with both surface and internal double micro-structures were obtained by loading the Gr,PANI and Gr/PANI on TPU electrospun fiber film,respectively,and then by employing the HPTP to print the surface micro-structure of fabric to surface of electrospun fiber film.In this work,the effects of filler type and hot-press time for devices performance were systematically investigated.And the Gr/PANI-TPU（MGPT）sensor with brilliant sensing property was obtained.Comparson with other sensors,MGPT sensor has a wide the rate detection range of 1～1000 mm/min,the high sensitivity of 0.143 k Pa^-1 with 0-6 k Pa strain.Besides,its strain cycle stability is brilliant,the response time（153 ms）and recover time（106 ms）is quick,and the durability with 1000 times load-release cycles is outstanding.Thus,the sensor also shows great response ability for monitoring micro-expression or micro-action in body application.