Intrinsic healable mechanochromic materials via incorporation of spiropyran mechanophore into polymer main chain

The development of multifunctional self-healing materials is highly demanding. Herein, an intrinsic healable mechanochromic (i-HMC) material was synthesized via the incorporation of spiropyran mechanophore into the polymer main chain. The as-synthesized i-HMC material exhibited mechanically induced color change as well as great self-healing performance. The mechanical properties of the damaged sample can be completely restored with a high healing efficiency of 98.3% and great toughness of 447 MJ/m3. The mobility behaviors of the polymer chain and hydrogen bonding interaction were analyzed through rheological measurements and in-situ FT-IR. The as-synthesized intrinsic materials are capable of dynamic, yet tough healable mechanochromic functions. In contrast to the composites, the intrinsic healable mechanochromic materials contain no foreign additives, which are highly potential for future applications in structural health detectors, load-bearing elements, and wearable devices.