Preparation And Research Of Polyurethane-based Flexible Stress-strain Sensor

With the popularization of intelligent terminal,flexible electronic products present a huge market prospect.Flexible stress-strain sensor is a new type of electronic equipment,flexible and strain sensor can make the friendly interaction between machines become a new field,developing rapidly.The advantages of flexible stress-strain sensors include flexibility,light weight,multiple functions and low cost.They are widely used in wearable electronics,human movement monitoring,personal health,artificial intelligence and other fields and have attracted much attention.Starting from the flexible stress-strain sensor,this paper carried out the following work:(1)Polyurethane emulsion was prepared from isoflurone diisocyanate and polyethylene glycol.Polyaniline/polyurethane composites were prepared by adding aniline monomer into polyurethane emulsion.The morphology and structure of polyaniline/polyurethane were characterized by SEM and FT-IR.GO solution was synthesized by improved Hummers method,and the structure of GO was characterized by Raman.(2)With polyaniline(PANI)/ polyurethane(PU)composite as flexible matrix material and micron silver flakes(AgMFs)as conductive filler,AgMFs/PANI/PU flexible stress-strain sensor was prepared by simple mixed curing process.AgMFs/PANI/PU flexible strain sensor has the advantages of high sensitivity(GF=173.66),short response time(10 ms),stable and reliable circulation(> 4000 times).Excellent sensor performance shows its unlimited health monitoring potential,such as joint movement,blinking,vocal cords,breathing and pulse beating.(3)The regular structure of the original template is printed on the polyurethane film in a way of copying to obtain the PU film with uneven surface.Reduced graphene oxide(rGO)/polyurethane(PU)films were prepared by drop coating and thermal reduction.The size and structure of rGO/ PU films were characterized by SEM,AFM,Raman and other detection methods.The rGO/ PU stress-strain sensor was obtained by using conductive copper foil tape as the conductor and polyimide tape as the packaging material.The cyclic stability of the bending of the rGO/ PU stress-strain sensor was tested(> 500 times),and the sensor was applied to the monitoring of the bending of fingers at different angles and the detection of pulse.(4)Combining LabVIEW data acquisition system with digital multimeter and self-made fixture,a cyclic drawing machine is designed.The bending,twisting,stretching and other cyclic tests detection of the flexible stress strain sensor were tested by the application of LabVIEW data acquisition system in the cyclic tensile machine,and the resistance variation of the flexible stress-strain sensor was obtained up to 4000 cycles.