Shenzhen Advanced Institute has developed a flexible stretchable product with low cost, printability, high conductivity and other functional characteristics.

Recently, the advanced electronic packaging materials research team led by Academician Wang Zhengping and the researcher led by Sun Rong of the Advanced Materials Research Center of the Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences have successfully developed a flexible kola with low cost, printability, high conductivity and other functional characteristics. The conductive material is stretched and successfully applied to the flexible strain sensor to realize real-time monitoring of human motion behavior. Research results A Low-Cost, Printable, and Stretchable Strain Sensor Based on Highly Conductive Elastic Composites with Tunable Sensitivity for Human Motion Monitoring (low-cost, printable, stretchable and sensitivity-adjustable strain sensors based on highly conductive elastic composites) And its application in human motion monitoring) is published online in the nano-core core journal Nano Research (DOI: 10.1007/s12274-017-1811-0, IF=7.354).

Flexible strain sensors with high stretchability, wide strain range, high sensitivity and good reliability have broad application prospects in the fields of electronic skin and human motion behavior monitoring systems. In general, high stretchability and high sensitivity are contradictory, because high stretchability requires a reasonable design to maintain the integrity of the material structure and morphology at large strains, while high sensitivity often requires small strains. A large number of sudden structural changes occur. How to achieve a balance between high sensitivity and high stretchability, and even high conductivity is still a challenge.

The team members Dr. Hu Yougen and Zhu Pengli, associate researcher, etc., based on the previous work on the controllability of hybrid conductive particles and the printability of flexible conductive composites (Journal of Materials Chemistry C, 2016, 4, 5839-5848) The core-shell polymer microspheres coated with metal silver hybrid conductive particles and polydimethylsiloxane composite, through the screen printing technology to achieve flexible circuit and flexible sensor large-area macro-simple preparation, effectively reduced The actual filling amount of the noble metal in the conductive composite material maintains a high electrical conductivity, and the spherical structure of the conductive filler is advantageous for improving the rheological behavior of the conductive paste and improving the printing adaptability. The sensor prepared at a silver content of only about 36.7 wt% exhibits high electrical conductivity (1.65 × 104 S/m), wide strain range (>80%), high sensitivity (6.0 to 78.6), and low resistance overshoot (<15). %) and excellent long-term damp heat stability (1750 h). In addition, the conductivity, mechanical properties and strain sensing performance of the sensor can be further controlled by controlling the filling amount of the hybrid conductive particles. Based on the above comprehensive performance, the conductive elastic composite material has been successfully applied to stretchable electrodes, flexible fine printed circuits and human motion behavior monitoring sensors, which fully demonstrates 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 R&D Special Project, the National Natural Science Foundation, 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.

Demonstration of mechanical flexibility and printability of conductive composites and their application in flexible printed circuits and monitoring of human motion behavior