Preparation Of Paper-based Carbon Nanotube Film And Study On Its Pressure Sensing Performance

At present,as an essential intelligent terminal in human-computer interaction,information acquisition and processing,intelligent recognition and communication,flexible sensor plays a very important role in the fields of electronic skin,intelligent manufacturing,physical signs monitoring and the Internet of things.According to the sensor mechanism,flexible pressure sensor can be divided into capacitance type,piezoelectric type,friction type and piezoresistive type.Among them,the piezoresistive flexible sensor has many advantages,such as simple structure,easy signal acquisition and preparation,which has been widely concerned by researchers.At present,the flexible pressure sensor has the problems of low sensitivity,narrow measurement range and poor stability.Therefore,how to select and design sensor sensitive materials and structures to solve the above problems is an urgent need in the field of flexible sensors.In order to solve the above problems,a paper-based carbon nanotube film/interdigital electrode flexible pressure sensor with large range and super sensitivity has been successfully developed.The uniform dispersion of carbon nanotubes was prepared by adding surface active materials and ultrasonic dispersion.At the same time,the paper-based carbon nanotube film has excellent electron transport capability and the distribution of carbon nanotubes on paper fiber is close and uniform.In order to improve the performance of the flexible pressure sensor based on the paper-based carbon nanotube film,the interdigital electrode was fabricated by photolithography to increase the conductive path of the flexible pressure sensor.The working mechanism of the sensor is that the change of the conductive path between the thin film materials of the flexible pressure sensor plays a leading role in the change of the sensor resistance during the high pressure test;When measuring the small pressure,the change of the conductive path between the film of the flexible pressure sensor and the interdigital electrode causes the change of the resistance of the sensor.To sum up,the synergistic effect of the internal conductive path of paper-based carbon nanotube film and the conductive path formed between paper-based carbon nanotube film and interdigital electrode endows the sensor with high sensitivity,large range,and good stability.After testing the electrical properties of the paper-based carbon nanotube film/interdigital structure electrode flexible pressure sensor,it is found that the sensor has high sensitivity(2.72 kPa^-1),its pressure measuring range is up to 140 kPa,and its response time is about 66 ms.The sensor can still maintain good sensing performance after 15000times of pressure cycling loading,which shows the excellent stability of the sensor.In the application exploration,the sensor shows a very low-pressure detection limit of about 8 Pa.At the same time,the flexible pressure sensor can not only measure human pulse,voice,wrist movement and other signals,but also prepare a sensor array to identify the size and distribution of space pressure,which verifies the feasibility of the sensor in the field of physical signs monitoring,intelligent manufacturing and human-computer interface.