A near infrared induced self-healable composite based on disulfide bonds for flexible electronics

Due to the damages caused during deformation of flexible electronic materials, the development of self-healing flexible electronic materials has received great attention. A self-healing flexible polyurethane nanocomposite obtained by the incorporation of carbon nanotubes (CNTs) is reported. The structure and self-healing properties of the nanocomposite were investigated by thermal analysis, tensile test and observation of surface morphology. After the introduction of CNTs, the tensile strength at break was improved from 1.45 MPa to 2.99 MPa as the loading content of CNTs was 5 wt%. The elongation at break decreased but still remained above 100%, indicating the composite was flexible enough for flexible and wearable electronics. Due to the photo-thermal effect of CNTs, the self-healing of the nanocomposite could be induced precisely, remotely and efficiently under irradiation of near infrared (NIR) laser without influencing the undamaged areas. The healing efficiency of the composite containing 3 wt% CNTs reached 90.1%. Besides, the nanocomposite could assist the recovery of the conductive layer coated on its surface under irradiation. Therefore, the polyurethane nanocomposite could be safely utilized as the flexible substrate for conductive layer of flexible electronics.