Recyclable Wearable Sensor Based on Tough, Self-Healing, Adhesive Polyurethane Elastomer for Human Motion Monitoring

Abstract

Although some progress has been achieved in flexible strain sensors, it is still a big challenge to develop sensors with excellent self-healing capability, adhesive, and recyclable properties for enhanced lifespan, facile operation, and decreased waste pollution in the flexible electronic field. In this study, we successfully synthesized the pyrene-terminated multifunctional polyurethane elastomer called PMFPU based on dynamic covalent bond and noncovalent hydrogen bonds, which integrates exceptional tough mechanical properties (the tensile toughness of 168.4 MJ/m 3 ), excellent self-healing performance (healing efficiency of 96%), superior adhesive property (shear strength as high as 1.46 MPa), and well-performed reprocessability (more than five cycles). Furthermore, we applied PMFPU in the fabrication of stretchable strain sensors based on the π−π stacking interactions between pyrene in PMFPU and carbon nanotubes (CNTs). Based on this unique design, the obtained flexible sensors can dissolve in THF and DMF solvents, enabling the reprocessing ability and avoiding electronic waste pollution. The stretchable strain sensors could detect human movements and facial expressions. Moreover, the sensors can restore stable sensing capabilities even after a repaired process or recyclable process, which is of significant importance for the development of environmentally friendly and highperformance sensors. The fabrication of these functional sensors holds broad application prospects in fields such as medical monitoring, human−machine interaction, and electronic skin.

Oxime-Urethane-Based Self-Healing Polyurethane for Achieving Complex Structures via 3D Printing

“…It was observed that as the temperature increased, all mechanical performance indicators improved, consistent with the earlier test results. To highlight the innovation in our work, Figure f compares the LNPU-3 with reported self-healing polyurethanes in terms of tensile strength, self-healing temperature, and self-healing period. ,− LNPU-3 demonstrates a leading position in all three aspects, providing more options for 3D printing materials and exploring additional possibilities for the application of self-healing materials.…”

Toward mechanically robust self-healing polyurethanes using dynamics chemistry

“…With the development of self-healing materials, the introduction of self-healing materials into wearable devices can not only improve the intelligence of wearable devices but also improve the reliability of their operation and extend their service life. Self-healing PU materials based on dynamic bonds can be used in a wide range of electronic devices, such as tactile sensors, 147 bending sensors, 148,149 strain sensors, 150–153 humidity sensors, 154 proximity sensors, 155 actuators, 156 electromyography sensors, 157 electrocardiogram sensors, 158 and light-emitting electrochemical cell displays. 159 The self-healing matrix is often combined with inorganic or metallic conductive materials to realize the integration of self-healing properties and sensing functions.…”