Hydrophobically Associated Functionalized CNT-Reinforced Double-Network Hydrogels as Advanced Flexible Strain Sensors

摘要

Hydrogels have gained the attention of researchers worldwide and can be widely applied for use in medical technologies in human health and in industrial applications such as robotics. However, producing a hydrogel with proper mechanical properties, low hysteresis energy, quick shape recovery, and long-range strain sensitivity is still an ongoing development. More development into hydrogel technology could also lead to an increase in the effectiveness and lifespan of artificial joint replacements. Our hydrogels can be incorporated into the development of highly sensitive strain sensors for wearable electronic devices. To work toward developing these technologies, multifunctional dual crosslinked hydrogels were developed using lauryl methacrylate, acrylamide, and acid-functionalized multiwalled carbon nanotubes (A-MWCNTs). Due to the dual crosslinking, the synthesized hydrogels display outstanding mechanical performance (high fracture stress, strain, toughness, and tensile strength). In shape recovery, the materials recover their original shape after compression and maintain hydrostaticity. A low hysteresis energy of 11.57 kJ m–3 makes it a suitable candidate for strain sensing with high sensitivity (GF = 9.2 at 500% strain) to monitor different human motions (wrist, neck movements, flexion of the fingers, swallowing, and during speaking). Additionally, due to its good mechanical properties, the cyclic stability was monitored up to 300 cycles and the hydrogel still was mechanically stable and had the fastest response–recovery time of less than 130 ms during mechanical performance studies. Our hydrogels can be used to develop highly sensitive strain sensors for wearable electronic devices.