Revolutionizing Thermal Stability and Self-Healing in Pressure Sensors: A Novel Approach

Abstract

Soft electronics, which require mechanical elasticity, rely on elastic materials that have both a small Young’s modulus and a large elastic strain range. These materials, however, are prone to damage when stress accumulates, presenting a significant challenge for soft electronics. To address this issue, the integration of self-healing functionality into these materials appears to be a promising solution. Dynamic covalent bond chemistry has been utilized to design high-strength polymers with controllable reversibility. Nonetheless, the temperature needed to trigger self-healing may induce thermal damage to other parts of the device. In contrast, if the self-healing temperature is reduced, the device might suffer damage when exposed to temperatures exceeding the self-healing point due to the low stability of the polymer at high temperatures. These challenges highlight the need for materials that can self-heal at low temperatures while maintaining thermal stability at high temperatures. In response to this challenge, we propose a novel approach that involves forming a microfibrous network using polycaprolactone (PCL), a material with a low melting temperature of 60 °C that is widely utilized in shape memory and self-healing materials. We fabricated the conductive fiber by encapsulating a microfiber PCL network with MXene nanosheets. These MXene nanosheets were seamlessly coated on the PCL fiber’s surface to prevent shape deformation at high temperatures. Furthermore, they exhibited high thermal conductivity, facilitating rapid internal heat dissipation. Consequently, the MXene/PCL microfiber networks demonstrated self-healing capabilities at 60 °C and thermal stability above 200 °C. This makes them potentially suitable for stretchable, self-healing electronic devices that need to withstand high temperatures.

Graphical abstract