3D Printed Polymer-based Conductive Composite Flexible Strain Sensor And Its Performance Researc

With the development of science and technology and the improvement of people’s living standards,flexible strain sensors are more and more widely used in medical and health care,wearable electronic devices,human-computer interaction,and intelligent robots.However,the current methods for preparing flexible strain sensors often have deficiencies that are difficult to overcome,such as high cost,lack of product design,and lack of flexibility in structural design.Fortunately,with the development of 3D printing technology,new ideas and solutions have been provided for the preparation of flexible strain sensors:by using 3D printing technology,flexible strain sensors with complex structures can be rapidly formed.In this work,a flexible strain sensor based on carbon nanotubes and thermoplastic polyurethane was prepared by using FDM in 3D printing technology.The research of this paper mainly includes the following contents:(1)the modified carbon nanotubes(M-CNT)and thermoplastic polyurethane(TPU)were used to print the strain sensor,and the addition of 1-pyrenecarboxylic acid(PCA)can conduct non-covalent modification of carbon nanotubes to improve the dispersion of carbon nanotubes in the matrix.The modified M-CNT/TPU strain sensor not only has high sensitivity(GF=3.21 at 20%strain)and stability,but also has good response behavior at a frequency of 0.01 to 1 Hz.(2)Hybrid nanofillers of carbon nanotubes and silver nanoparticles(AgNP)were prepared by a hydrothermal method.The synergistic effect between carbon nanotubes and silver nanoparticles is conducive to improving the dispersibility of carbon nanotubes in the matrix and further improving the CNT/AgNP/TPU prints the sensitivity of the strain sensor(GF=5.97 at 20%strain).(3)The synergistic effect between graphite nanoplatelets(GNP)and carbon nanotubes is used to improve the conductive network structure.The existence of graphite nanoplatelet plays a role in bridging carbon nanotubes and improves the dispersion of carbon nanotubes.At the same time,it significantly improved the conductivity and sensitivity of CNT/GNP/TPU printed strain sensors(GF=22.6 at the strain of 20%).In addition,we applied the printed flexible strain sensor to the monitoring of human physiological activities.The experimental results show that the printed strain sensor has good response behaviors to limb movements,sports breathing,and swallowing sounds,indicating that the printed strain sensor is useful in medical treatment.Great application potential in sanitary and wearable electronic devices.