Outstanding temperature-tolerant conductive polyacrylamide/sodium carboxymethylcellulose hydrogel with ultra-stretchability and good strain sensing performance

摘要

Flexible sensors based on conductive hydrogels have shown surprising potential in the field of electronic skin and human-computer interaction. However, pure water in the hydrogel will inevitably freeze at low temperature or evaporate quickly in dry environment, resulting in the failure of hydrogel as a flexible sensor. Here, inorganic ions (Li+ and Cl-) and glycerol were introduced into the polyacrylamide/sodium carboxymethylcellulose (PAM/CMCNa) composite hydrogel networks through the strategy of solvent replacement. The optimized hydrogel had a quite large elongation at break of 2000%, and a breaking strength of more than 0.14 MPa. The synergistic effect of inorganic ions and glycerol enabled the hydrogel to maintain a good flexibility in a wide temperature range of -20-45 degrees C, which could meet the work needs of the hydrogel in high temperature or extremely cold environments. The hydrogel showed a very wide working range of 1000%, a fast response time of 150 ms, and a high stability and repeatability of 500 cycles during strain sensing detection. Besides, the hydrogel could capture the large and subtle body movements accurately and stably. Therefore, this hydrogel may be applied as in wearable sensing devices used in extreme environments.