| Flexible strain sensors have recently become a current research hotpot in modern science development due to their widespread employment in various applications.The market for flexible strain sensors is gradually getting signification attention due to its smart sensing mechanism,and requirements for excellent performance are now being established.Therefore,a flexible strain sensors with high sensitivity,ease of fabrication,low price,and mass research and development is demanded.In this paper,AgNP/polydopamine(PDA)/latex sponge pressure sensors,TPU/AgNF strain sensors,AgNF/hydroxypropyl methyl cellulose(HPMC)/TPU strain sensors and TPU/ACNT/AgNF strain sensors were prepared using latex sponge and thermoplastic polyurethane(TPU)as substrate materials and silver nanoparticles(AgNP),silver nanoflowers(AgNF)and acidified carbon nanotubes(ACNT)as conductive materials based on the piezoresistive effect.The structures and properties of the prepared flexible sensors were characterised and tested.My research was conducted in the following three aspects:(1)AgNP/PDA/latex sponge composites were prepared by in situ reduction using latex sponge with excellent resilience as the substrate material and modified with PDA to assemble them into pressure sensors.The AgNP/PDA/latex sponge composites with different electrical conductivities were prepared using silver nitrate solutions with concentrations ranging from 2.5 wt%to 15 wt%,and the resistivity of the composites ranges from 1.05 ×107 to 1.25 × 102 ?·cm.A strain of 50%was applied to the sensor made of AgNP/PDA/latex sponge composite at different compression rates.The rate of change of resistance graphs for sensors prepared with silver nitrate concentrations of 2.5 wt%-7.5 wt%are consistent with the strain applied to the sensors.The sensing performance of the sensors prepared for a silver nitrate concentration of 2.5 wt%was systematically investigated with a sensitivity of-81 and a strain range of 0-80%,with a stable rate of change in resistance at different strains or different compression rates.(2)AgNF has been prepared by complexing silver nitrate and potassium citrate,and TPU/AgNF strain sensors and AgNF/HPMC/TPU strain sensors have been prepared by casting with TPU as the base material and HPMC as the dispersant and film-forming agent.Study on the response,sensitivity,strain range and stability of the TPU/AgNF-0.03 strain sensor and AgNF/HPMC-0.001/TPU strain sensor Compared with the TPU/AgNF-0.03 strain transducer,the AgNF/HPMC-0.001/TPU strain transducer has a higher degree of response and sensitivity(2.8×108),but a smaller strain range and stability.Morever,the TPU/AgNF-0.03 and AgNF/HPMC-0.001/TPU strain sensors can be used for human motion monitoring,such as the bending of fingers,wrists,knees and the stretching of skin when clenching a fist.(3)TPU/ACNT/AgNF fibre membranes have been prepared by impregnation sonication using TPU fibre membranes prepared by electrostatic spinning as the substrate material,and TPU/ACNT/AgNF fibre membranes have benn prepared by multiple in-situ reductions.A fiber membrane with an ultrasonic time of 50 min and an in situ reduction number of 4 was selected as the strain sensor.The TPU/ACNT-50/AgNF-4 strain sensor has a wide detection range of 100%,high sensitivity(GF=58912)and low detection(strain of 0.5%),and also has excellent stability,with the rate of change in resistance remaining stable during a 10,000s cycle test.It also has great potential for human motion detection. |
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