writer：Lian Han, Songbo Cui, Hou-Yong Yu, Mei-Li Song, Haoyu Zhang, Nathan Grishkewich, Congguo Huang, Daes
keywords：cellulose nanocrystals，cellulose nanofibers，polypyrrole; nanocomposites，skin sensors
source：期刊
specific source：ACS Applied Materials & Interfaced
Issue time：2019年

Electronic skins are developed for applications such as biomedical sensors, robotic prosthetics and human-machine interactions, which raises the interests in composite

materials that possess both flexibility and sensing properties. Polypyrrole (PPy) coated cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) were prepared using iron (III) chloride (FeCl3) oxidant were used to reinforce polyvinyl alcohol (PVA). The combination of weak H-bonds, iron co-ordination bonds and the synergistic effect of these components yielded self-healing nanocomposite films with robust mechanical strength (409% increase compared to pure PVA and high toughness up to 407.1%), and excellent adhesion (9670 times greater than its own weight) to various substrates in air and water.When damaged, the nanocomposite displayed good mechanical (72.0-76.3%) and

conductive recovery (54.9-91.2%) after a healing time of 30 min. More importantly, the flexible nanocomposites possessed high strain sensitivity under subtle strains (than the gauge factor of ionic hydrogel-based skin sensors. This nanocomposite film possessed superior sensing performance for real-time monitoring of large and subtle human motions (finger bending motions, swallowing and wrist pulse), thus they have great potentials in health monitoring, smart flexible skin sensors and wearable electronic devices.