Preparation And Properties Of Graphene-Based Flexible Strain Sensor

With the expansion of the smart wearable device market,the development of flexible electronics continues to deepen.Flexible sensor which is to sense various stress signals of complex sensors on complex surfaces has received extensive attention,because their application prospects in areas such as smart medical,health monitoring,h?man-computer interaction,and intelligent robots.Graphene has in-depth research on nanocomposites,flexible microstructured electronic devices because of its excellent electrical and mechanical properties,which provides an advantageous basis for the preparation of flexible mechanical sensors.In this paper,a flexible sensor for the study of micro-strain signals on the skin surface had been produced,and the optimal preparation process for small-size graphenes with flexible stress sensors is studied.Two kinds of flexible strain sensors based on laser direct writing pattern structure and flexible stress sensors based on compound nanoparticles were designed and prepared.The effects of nanoparticles composite structure on the force and electrical characteristics of the sensor were systematically researched.First of all,the paper analyzes ultrasonic dispersion method and the redox method.The size and n?mber of layers of graphene fragments obtained depends on the ultrasonic power and time of the ultrasonic process.Ultrasound time plays a similar role.A graphene oxide dispersion was well prepared using ultrasonic power of 50 W?ultrasonic time of 15 minute and three times of laser direct writes are the best degree of graphene oxide reduction.Two graphene-structured flexible graphene stress sensors were designed and the force-electricity characteristics of the sensor were tested.Experiments show that in the graphene-based flexible stress sensor,the length-width ratio of the graphene channel of the sensing unit will directly affect the sensitivity of the sensor.The sensitivity of the graphene flexible stress sensor with an aspect ratio of 5 is 8,and the sensitivity of the graphene flexible stress sensor with an aspect ratio of 100 can reach 36,the sensor's response time is 300 ms.The strain range of the double layers contact graphene flexible stress sensor will be improved,and the test results can still be maintained at a strain of 30%.The measurable strain range is greatly improved,and the linearity of the sensor is excellent.The response time is 150 ms.For the sensitive sensing requirements of surface micro-strain signals,a flexible stress sensor based on nanoparticles/graphene composite material was innovatively designed,the stress response mechanism of the sensor was analyzed,and the sensor was prepared.The sensor test results show that the device has ultra-high sensitivity,which is more than 30 times that of the uncomposited nano-sphere graphene sensor.Test data shows that this small-size sensor has a sensitivity of up to 250 and can resolve very small strains of 0.35%.Finally,the prepared high-sensitivity sensor is used for h?man body signal testing.The test result shows that the prepared high-sensitivity sensor can detect and distinguish h?man swallowing signals.The analysis of the signal can identify whether the food is swallowed into the stomach completely and will be used to treat strokes.The patient is monitored and protected;the sensor can also be used to identify the back static sitting position to prevent the occurrence of l?mbar disc herniation and other diseases.