Research On Capacitive Noninvasive Thickness Sensor Based On Printing

The real-time thickness detection is of great significance for the monitoring of the working conditions of easy-to-wear devices.Although existing thickness detection equipment such as laser thickness sensors,ultrasonic thickness sensors,capacitive thickness sensors,can be used for conventional thickness measurement,their large size,rigid probes,and expensive prices limit their use in complex engineering.Applications and wide-scale promotion.As an emerging field,printed electronics has developed rapidly in recent years.Because of its advantages such as low cost,easy manufacturing,small size,and high compatibility with flexible substrates,printed electronics have received widespread attention in academia and industry.Functionalized carbon nanotube composites(CNT @ Ag composites)with nano silver particles are considered as candidate materials for printed sensors due to their potential properties such as low contact resistance and excellent mechanical properties.But so far,most of the results have failed to meet expectations,and the electrical conductivity of carbon nanotube composites functionalized with silver nanoparticles has been severely reduced.This may be due to its two key problems: first,carbon nanotubes(CNTs)are spontaneously bound together due to strong Van der Waals force interactions;second,due to covalent bonds between carbon atoms and sp2 hybrids Connected,carbon nanotubes have high chemical stability as integrated molecules.In this paper,a new type of nanometer metal particle functional carbon nanocomposite is prepared by chemical modification.The production of nanometer metal particles is controlled by rationally adjusting the ratio of carbon nanomaterials to nanometer metal particles and using hydrazine hydrate or formaldehyde as a reducing agent.After growing up,the distribution of carbon nanotubes and silver nanoparticles was controlled by ultrasonic and dispersant-assisted methods.For the first time,functionally dispersed carbon nanotube composites with functionally dispersed silver nanoparticles were prepared.The printing-based contact non-invasive thickness sensor prepared by using nano-silver particle functionalized carbon nanotube composite material ink has excellent sensitivity,which is about 20 times higher than that of the capacitive thickness sensor that has been prepared in the current academic circle.The sensitivity is 0.5167 p F /mm in the range of 0-6.0mm.At the same time,combined with the optimization of printing patterns and printing methods,the characteristics of carbon nanocomposite materials enhanced by nano metal particles are maximized.Finally,this article will also analyze the theoretical performance of the sensor based on the finite element simulation software COMSOL,and also show the sensor's mid-thickness measurement in Io T devices including automobile tires.