Research On Airbag Flexible Pressure Sensor Based On Pressure Measurement Of Compression Stocking

Medical compression stockings,as an effective medical device textile for preventing and treating varicose veins of lower extremities,the measurement and distribution of pressure have become a topic of concern today.Flexible pressure sensors can sense external pressure stimuli and convert them into collectible electrical signals,which are important means of compression stocking pressure measurement.Based on the structural characteristics of medical compression stockings,this paper combines carbon nanotubes/polyurethane porous conductive composite films with conductive silver paste flexible electrodes to design and fabricate a balloon-type flexible pressure sensor,which is applied to the static pressure measurement of compression stockings.At the same time,the pressure distribution law of different grades of compression stockings was studied.First,carbon nanotube/polyurethane porous conductive composite films were prepared by non-solvent-induced phase separation method,and the effects of carbon nanotube content on the microscopic morphology,electrical properties and piezoresistive response properties of the conductive composite films were explored.The results show that in the pressure range of 0.5-10kPa,the conductive composite film with a carbon nanotube content of 10%has the best comprehensive performance,the highest sensitivity is 36.41kPa-1,and the hysteresis and repeatability errors are± 10.87%and ± 13.95%,Then,the conductive silver paste flexible electrode was prepared by screen printing method,and the effects of substrate material,curing temperature and curing time on the curing reaction of the conductive silver paste c oating,that is,the effects on the mechanical and electrical properties of the flexible electrode were investigated.The results show that the more complete the curing reaction of the silver paste coating is,the lower the resistivity of the flexible electrode is,and the more stable the electrical properties are under tensile and bending deformation conditions.Among them,the flexible electrode with PVC film as the base material still maintains excellent electrical properties after being stretched at 3%tensile rate or 30,000 times of bending,and the resistance change rates are 15.10%and 3.65%.Finally,the carbon nanotube/polyurethane conductive composite film and the conductive silver paste flexible electrode were combined,and the balloon sensor was assembled by hot pressing method,and the accuracy and stability of the pressure measurement of the sensor were tested.The results show that in the pressure range of 10-100mmHg,there is a strong linear correlation between the measured pressure value of the sensor and the theoretical pressure value,the correlation coefficient is close to 1,and the maximum difference is only 3.02mmHg;the repeatability standard deviation of the sensor is up to 0.37mmHg,and the maximum coefficient of variation is only 0.85%,In order to verify the practicability of the prepared airbag-type flexible pressure sensor,the sensor was applied to the static pressure measurement of different grades of compression stockings,and combined with the finite element simulation,the pressure distribution law of the compression stockings was futher explored.It provides a reliable data basis and basis for future research on the static pressure distribution of compression stockings.