Modulation Of Piezoresistive Performance Of Stretched Film Sensor Based On“PEDOT:PSS/rGo@PS Particles”

The flexible film stretch sensor has the advantages of small size,high adhesion to the measured object,and simple preparation method.Wide-range,high-sensitivity thin-film sensors can simultaneously meet the requirements of devices for detecting small and large strains,and have become a research hotspot today.In the sensor device with hybrid conductive network,the "stress defect" of the conductive network can be controlled to solve the problem of uncontrollable breakpoint when the conductive path is disconnected,and a high-performance sensor device with adjustable sensitivity is obtained.The thesis first blends polyethylene dioxythiophene/polystyrene sulfonate(PEDOT:PSS)with water-based polyurethane(PU),and then incorporates the prepared reduced graphene oxide@polystyrene(r GO@PS)composite particles,And then form a film by emulsion to obtain a flexible film sensor.The preparation method of r GO@PS particles was studied in turn;the influence of factors such as PEDOT:PSS and r GO@PS content,r GO@PS particle size on the strain sensitivity and range of stretched film sensors,and a method for adjusting the sensitivity of film sensing materials was proposed.And it was verified,and the following results were obtained:(1)The co-aggregation of GO and PS is induced by sodium chloride,and after reduction-washing-ultrasonic dispersion steps,r GO@PS composite particles are obtained,which are adsorbed on the surface of PS particles through ?-? interaction,and then subjected to VC(ascorbic acid)The r GO@PS particles were obtained by reduction;the composite particles did not appear analytical attachment and aggregation within 24 h,and they had excellent stability;(2)When the PS particles with a size of 453 nm are used to adsorb GO,when the size of the GO sheet decreases from 290 nm to 240 nm to 190 nm,the capacity of PS particles to adsorb GO is slightly increased,and the maximum adsorption capacity is 0.0190g/ g,0.0192g/g,0.0198g/g;PS particles with particle sizes of 256 nm,453 nm and 501 nm are used to adsorb 190 nm GO respectively.As the particle size of PS particles increases,the saturated adsorption capacity decreases,successively 0.0199 g /g,0.0198g/g,0.0194g/g;(3)Compared with the composite film formed by PEDOT:PSS and PU,the r GO@PS/PEDOT: PSS/PU film sensor formed by adding r GO@PS has significantly higher modulus,elongation at break and electrical conductivity,while the seepage threshold is reduced.,The cycle response performance is improved,and the hysteresis error is reduced,indicating that the latter is more suitable for preparing high-performance sensors;(4)When the content of PEDOT:PSS in the PEDOT:PSS/r GO@PS/PU thin film sensing material is higher than the percolation threshold,as the content of PEDOT:PSS increases,the sensitivity of the resulting sensor at small strains(<30%)gradually decreases.When the strain is large(>30%),the sensitivity gradually increases;when the content of PEDOT:PSS in the fixed film,the added r GO@PS does not change the sensitivity of the sensor when the sensor is small(<30%),but when the strain is large(>30%)The sensitivity of the sensor gradually increases with the increase of the content of composite particles;in addition,when the particle size of the r GO@PS composite particles is reduced,the sensitivity of the sensor decreases at large strains(>30%),but the stress response range is widened.Therefore,based on the design of the content of PEDOT:PSS and the content and particle size of r GO@PS composite particles in the film,the sensitivity of the sensor can be independently adjusted for small strain and large strain interval;(5)The composite film sensor has excellent strain response performance: stable cyclic response performance(500 cycles stretch),small hysteresis error(6.1%),fast response time(<60m S)and good high-frequency stretch response.In addition,The sensor device also has a very good performance in human body sign monitoring,not only can detect the joint movement of large deformation(>50%),but also can realize the monitoring of the small movement of the neck muscles(<5%)when swallowing and speaking.