PVA/KGM dual network hydrogels doped with carbon nanotube-collagen corona as flexible sensors for human motion monitoring

Abstract

Hydrogel strain sensors with features such as frost resistance, high biocompatibility, and volume stability have shown irreplaceable advantages in many fields. Herein, a “part assembly” strategy is proposed in which carbon nanotubes and collagen are designed as two “parts” that are assembled to obtain collagen protein corona (PC) and introduced into the polyvinyl alcohol (PVA)/konjac gum (KGM) composite hydrogel interior, preparing a double network composite hydrogel of PVA/KGM/PC. The first network structure is formed by the interaction of PVA and glycerol, and the second network structure is formed by the interaction of the KGM itself. The prepared PVA/KGM/PC composite hydrogel has good mechanical properties, frost resistance, high sensitivity, and a wide range of strain responses, with strains of 226% and 222.5% at room temperature and −20 °C, respectively. It can monitor not only the human arm, knee bend, and other large ranges of motion but also the human heartbeat, pulse and other small ranges of physiological activities. In addition, the Gauge factor of the hydrogel can reach 3.38. The PVA/KGM/PC composite hydrogel containing collagen corona prepared in this study can be extensively used as a flexible strain sensor in emerging fields, such as medical monitoring, intelligent robotics, and wearable devices, providing a new strategy for optimizing the preparation process of hydrogels.