Self-healable and Robust Silicone Elastomer for Ultrasensitive Flexible Sensors

Abstract

Capturing human motions using wearable electronics provides tremendous opportunities for human–machine interfaces. However, current flexible sensors are always challenged due to the contradiction between the self-healing property and mechanical performance of the flexible matrix. Moreover, the strain sensing range of current sensors is always limited within 5% due to the ineffectiveness of conductive components upon larger strain. Inspired by the synergistic combination of hydrogen bondings and metal coordination, a self-healable elastomer was synthesized, which displayed a tensile strength of 1.73 MPa and a self-healing efficiency of 93%. Moreover, the designed flexible sensor using a synthesized silicone elastomer substrate and a carbon nanotube conductive component displayed a high gauge factor of 1198 contributed by the cooperation of the wrinkle structure and the microcrack mechanism. The flexible sensors exhibited a fast response of 129 ms due to the excellent adhesion of the conductive layer upon the substrate. Furthermore, a wearable intelligent gesture capturing system integrating an elastomer-based sensor and a wireless electronic control module was successfully developed to realize the real-time monitoring of hand gestures. Thus, the developed silicone elastomer-based sensor holds high potential for human–machine interfaces and provides a novel pathway for hand rehabilitation training.

Zwitterion-Incorporated Antifreeze Hydrogel with Highly Stretchable, Transparent, and Self-Adhesive Properties for Flexible Strain Sensors

“…It can be repeatedly peeled off and removed without any residual or allergic reactions. The excellent adhesion of the PHEA/ZP hydrogel to different substrates is mainly due to the introduction of ZP in PHEA, which provides the hydrogels with rich functional groups such as amino, hydroxy, and carbonyl groups, resulting in a large number of hydrogen bonds and intermolecular interactions on the substrate surface . Meanwhile, carboxyl groups in ZP can form metal coordination bonds with metal ions on the surface of the substrate to achieve adhesion.…”

“…The excellent adhesion of the PHEA/ZP hydrogel to different substrates is mainly due to the introduction of ZP in PHEA, which provides the hydrogels with rich functional groups such as amino, hydroxy, and carbonyl groups, resulting in a large number of hydrogen bonds and intermolecular interactions on the substrate surface. 37 Meanwhile, carboxyl groups in ZP can form metal coordination bonds with metal ions on the surface of the substrate to achieve adhesion. Therefore, the PHEA/ZP hydrogel can be used as a wearable strain sensor attached to human skin for detecting human movement and physiological signals and protecting the skin from electrical damage.…”

Magneto-Induced Janus Adhesive-Tough Hydrogels for Wearable Human Motion Sensing and Enhanced Low-Grade Heat Harvesting

“…Hydrogels have become ideal materials for implantable devices, wound dressing, and flexible electronics . To meet the needs of these applications, the structure and performance of hydrogels need to be optimized, such as, self-healing, antifreezing, adhesion of hydrogel sensors, − ionic transport, heat conductivity, and adhesion of hydrogel thermoelectrics . Obviously, adhesion is critical for the harmonious combination of the hydrogel and the substrate .…”

Mussel-inspired PDA@PEDOT nanocomposite hydrogel with excellent mechanical strength, self-adhesive, and self-healing properties for a flexible strain sensor

“…Usually, most conductive hydrogels are prepared by combining hydrogel substrates with conductive nanomaterials (nanowires, carbon nanotubes) or intrinsically conductive polymers (polyaniline, sodium polystyrene sulfonate). [6][7][8][9][10] However, particle deposition and poor interfacial compatibility reduce the mechanical and electrical properties of conductive hydrogels. [11][12][13] Therefore, there is an urgent imperative to improve the dispersibility of the conductive nanofillers.…”