Study On The Fabrication And Pressure Sensing Characteristics Of Flexible Piezoelectric Film

With the continuous improvement of living standards,people’s physical health has gradually been paid attention to.Biomedicine electronic devices are popular because of their portability,sensitivity and real-time monitoring.These medical electronic devices can not only monitor the basic biological parameters of the human body in real time during human activities,but also transmit to the handheld terminal devices through wireless terminal devices,and realize multi-platform sharing using Internet technology to make judgments on the physical condition.Among them,the flexible strain sensor with high sensitivity,as the most basic device for detecting biological signals,is crucial for the accurate and timely collection of biological signals.Therefore,it is of great significance to prepare flexible strain sensors with high sensitivity,high flexibility,good repeatability,low cost and simple structure.In this thesis,the working mechanism of flexible pressure sensor was discussed in depth.By comparing several flexible pressure sensors with different sensitive mechanisms,we selected PZT nano ceramic fiber prepared by electrostatic spinning technology as the piezoelectric material and mixed it with the polymer PDSM to prepare a flexible composite film as the functional layer,the flexible ITO-PEN was used as the bottom electrode and substrate.In addition,COMSOL simulation was used to further explore the influence of different PZT contents on the piezoelectric properties of the functional layer.Secondly,we used X-ray diffraction analyzer,scanning electron microscope,ferroelectric tester and other equipment to characterize the morphology and ferroelectric properties of the sensor functional layer,the results show that the piezoelectric composite film has high density,uniform distribution and excellent ferroelectric properties.Thirdly,the flexible piezoelectric sensor was tested with a self-built testing platform,and the results show that the flexible device has good flexibility,durability,and electro-mechanical response characteristics.Finally,the flexible piezoelectric sensor was combined with the wearable device and fixed on the human hand,elbow,knee and wrist for gesture recognition and vital signs monitoring.Furthermore,a3 x 3 array sensor was fabricated based on the sensor,its response output was monitored by applying forces at different positions and areas,the test results show that the pressuredistribution can be monitored in real time.The flexible piezoelectric sensor prepared in this paper has the advantages of simple preparation process,stability,durability and high sensitivity,it has great potential in medical testing and so on.