Self-Healing, Recyclable Substrate Boosts Soft Sensor Durability
Researchers have developed a novel biosubstrate that can self-repair, strongly adhere to conductive metals, and be remolded or broken down, enhancing the longevity and recyclability of soft electronic devices.
Soft sensors, crucial for applications like health monitoring and virtual reality, often suffer from conductor detachment due to repeated bending and friction, as well as physical damage. Environmentally unfriendly, petroleum-derived substrates further complicate their lifecycle. To address these issues, a team at the National University of Singapore's College of Design and Engineering (NUS CDE) has engineered a new material, termed an intrinsically dynamic biosubstrate (IDBS).
Developed by researchers led by assistant professor Zhai Wei, IDBS is synthesized by combining naturally occurring lipoic acid and phytic acid. This process creates a molecular network strengthened by three types of bonds: dynamic disulfide bonds for self-repair, stable ester bonds for structural integrity, and energy-absorbing hydrogen bonds for stretchability and adhesion. This unique combination allows the material to withstand significant stretching, with one formulation extending over eight times its original length.
The IDBS demonstrates remarkable self-healing capabilities. Damaged samples recovered over 90% of their strength within 24 hours at room temperature, maintaining over 90% repair efficiency through five cycles. Furthermore, the substrate exhibits superior adhesion to metals commonly used in soft electronics. When heated, IDBS polymer chains become more mobile, forming stronger bonds with zinc and silver conductors, resulting in adhesion strengths significantly greater than those achieved with conventional materials like PDMS and SEBS.
Prototypes utilizing IDBS for electronic skin successfully tracked temperature, moisture, and strain, with silver electrodes capturing heart and muscle signals comparable to commercial standards. After extensive friction testing, the IDBS-based electrodes maintained clear signal output, unlike those on PDMS which showed signal deterioration. The heat-responsive nature of IDBS also facilitates end-of-life disassembly, allowing for the recovery of valuable components before the substrate is remolded or broken down using ethanol.
This development of a self-repairing and recyclable substrate is significant for soft electronics, moving beyond passive support to an active component enhancing device longevity and sustainability. The strong, heat-assisted adhesion to conductors and facile disassembly offer a pathway to more robust and environmentally conscious wearable sensors, potentially reducing e-waste and enabling longer operational lifespans for critical health monitoring and interface technologies.
Edited by the news editor with AI from the original report — please refer to the original source.