New progress made in research on flexible printed conductive materials and sensors in Shenzhen Advanced Institute

Demonstration of Mechanical Flexibility and Printability of Conductive Composites and Their Application in the Field of Flexible Printed Circuits and Monitoring of Human Motion Behavior

Recently, the Advanced Electronic Packaging Materials Research Team led by Wang Zhengping and Sun Rong of the Institute of Advanced Materials, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences successfully developed a flexible and stretchable conductive material with low cost, printability, and high electrical conductivity. Materials, and successfully applied to flexible strain sensors, to achieve real-time monitoring of human motion. Research results “Low-cost, printable, stretchable, and adjustable sensitivity strain sensors based on highly conductive elastic composites and their applications in the monitoring of human locomotion” published online in the journal Nano Nano (DOI: 10.1007/ S12274-017-1811-0) on.

The flexible strain sensor with high stretchability, wide strain range, high sensitivity and good reliability has broad application prospects in the fields of electronic skin, human motion behavior monitoring system and the like. In general, high stretchability and high sensitivity are contradictory, because high stretchability requires a reasonable design to maintain the integrity of the structure and morphology of the material at large strains, while high sensitivity is often required at small strains. There are a lot of sudden structural changes. How to achieve a balance between high sensitivity and high stretchability and even high conductivity is still a challenge.

The team members Hu Yougen, Zhu Pengli, etc., based on the previous work on the controlled preparation of hybrid conductive particles and the study of the printability of flexible conductive composites (Journal of Materials Chemistry C, 2016, 4, 5839-5848), using core shells The hybrid conductive particles coated with metallic silver on the surface of the structural polymer microspheres are composited with polydimethylsiloxane, and the large-area macroscale preparation of the flexible circuit and the flexible sensor is realized by the screen printing technology, effectively reducing the conductive composite. The actual amount of noble metal in the material and maintain a high electrical conductivity, while the spherical structure of the conductive filler is conducive to improving the rheological behavior of the conductive paste and improve the printing adaptability. The sensor prepared when the silver content is only about 36.7 wt% shows high conductivity (1.65 × 104S/m), wide strain range (>80%), high sensitivity (6.0 ~ 78.6), low resistance overshoot (<15 %) and excellent long-term hydrothermal stability (1750 h). In addition, by controlling the filling amount of the hybrid conductive particles, the conductivity, mechanical properties and strain sensing performance of the sensor can be further regulated. Based on the above-mentioned good comprehensive performance, the conductive elastic composite material has been successfully applied to stretchable electrodes, flexible fine printed circuits, and human motion behavior monitoring sensors, and has fully demonstrated its good application value in the field of flexible wearable electronics.

The research results provide an effective technology and reference for the development of low-cost flexible printable conductive materials and flexible strain sensors.

The project was supported by the National Key Research and Development Program, the National Natural Science Foundation of China, the Key Laboratory of High Density Electronic Packaging Key Materials of Guangdong Province, and the Outstanding Youth Innovation Fund of the Shenzhen Advanced Institute of the Chinese Academy of Sciences.