Research And Application Of Flexible Sensor And Its Integration In The Field Of Humanoid Sensory System

With the development of microelectronics,flexible electronics and bionic electronics,more and more studies on the flexibility,miniaturization,high integration and multi-function are carrying on for the bionic sensors and integrated systems.This development trend also promotes more in-depth bionic simulation of biological sensing system by bionic electronic products,so as to develop more sophisticated bionic devices to simulate the sensing function of organisms.At the same time,by integrating different bionic sensors or bionic sensors with electronic devices with other functions,we can simulate the complex perception system of human body(such as skin feeling touch and temperature at the same time),and even the advanced functions of the sensory system(such as tactile learning,tactile memory,visual learning,etc.).This paper is devoted to the development of bionic sensor and its integrated system which can simulate the function of human sensory system,and has carried out a series of research work from the aspects of device structure design,material selection and systematic integration.The research contents of this paper are as follows:(1)A flexible pressure sensor array with anti-interference to temperature and humidity is designed.The hybrid film of the sensor is composed of multi-walled carbon nanotubes(MWCNTs)with negative temperature coefficient(NTC)and graphite powder(GPs)with positive temperature coefficient(PTC).This unique film structure effectively eliminates temperature interference.To achieve waterproof behaviors,the device is sealed by ethylene-vinyl acetate copolymer(EVA).The obtained flexible pressure sensor has ultra-high sensitivity,fast response time and good high-frequency response stability.A 5x5 sensors array is fabricated for spatial pressure distribution imaging.The pressure sensors array has good anti-environmental interference performance,high sensitivity,and stability.This pressure sensor can accurately detect the touch sense in a complex and changeable environment,and has a certain application prospect for the commercialization of electronic skin in the future.(2)A dual-function self-healing electronic skin that can detect and recognize different stimuli and have self-healing capacity is designed.Using polyurethane,polyurethane@multi-wall carbon nanotubes and cellulose nanocrystals@carboxylated nitrile rubber@polyethyleneimine with good elasticity,flexibility and self-healing ability as pressure-sensitive materials,temperature-sensitive materials and substrates,respectively,an electronic skin with integrated temperature and pressure sensing is made by hot pressing method.Each type of sensors inside the electronic skin shows a fast and precise response to the target stimulus.At the same time,due to the self-healing ability of polyurethane and cellulose nanocrystals@butyl-nitrile-rubber@polyethyleneimine,it can also self-repair after damage,and the repaired electronic skin still maintains good temperature and pressure sensitivity.In addition,a 5×5 device array was fabricated to simultaneously map the pressure and temperature distribution with maintained self-healing ability.The electronic skin device inspires new ideas in the fields of artificial skin,human-machine interface and biological monitoring equipment.(3)An artificial olfactory system integrating Sr-ZnO gas sensor,HfO_x-memristor and electrochemical actuator is designed.The system can recognize,sense,memorize and activate motions to NH₃ gas.The Sr-ZnO gas sensor can sense and identify NH₃ through the change of resistance,and transmit the signal to the memristor,so that it can switch the resistance state to store NH₃ information.At the same time,the activation of memristor can also trigger the movement of the electrochemical actuator,thus blocking the airflow channel,which is similar to the conditioned reflex of covering the mouth and nose with hands when human smell irritating NH₃.The artificial olfactory system provides a potential strategy for future bioinspired electronics,especially for the imitation of biological sensory systems.