Self-healing, stretchable and recyclable polyurethane-PEDOT:PSS conductive blends.

Future electronics call for materials with mechanical toughness, flexibility, and stretchability. Moreover, self-healing and recyclability are highly desirable to mitigate the escalating environmental threat of electronic waste (e-waste). Herein, we report a stretchable, self-healing, and recyclable material based on a mixture of the conductive polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) with a custom-designed polyurethane (PU) and polyethylene glycol (PEG). This material showed excellent elongation at brake (∼350%), high toughness (∼24.6 MJ m-3), moderate electrical conductivity (∼10 S cm-1), and outstanding mechanical and electrical healing efficiencies. In addition, it demonstrated exceptional recyclability with no significant loss in the mechanical and electrical properties after being recycled 20 times. Based on these properties, as a proof of principle for sustainable electronic devices, we demonstrated that electrocardiogram (ECG) electrodes and pressure sensors based on this material could be recycled without significant performance loss. The development of multifunctional electronic materials that are self-healing and fully recyclable is a promising step toward sustainable electronics, offering a potential solution to the e-waste challenge.

Recent Progress on Self-Healable Conducting Polymers.

Materials able to regenerate after damage have been the object of investigation since the ancient times. For instance, self-healing concretes, able to resist earthquakes, aging, weather, and seawater have been known since the times of ancient Rome and are still the object of research. During the last decade, there has been an increasing interest in self-healing electronic materials, for applications in electronic skin (E-skin) for health monitoring, wearable and stretchable sensors, actuators, transistors, energy harvesting, and storage devices. Self-healing materials based on conducting polymers are particularly attractive due to their tunable high conductivity, good stability, intrinsic flexibility, excellent processability and biocompatibility. Here recent developments are reviewed in the field of self-healing electronic materials based on conducting polymers, such as poly 3,4-ethylenedioxythiophene (PEDOT), polypyrrole (PPy), and polyaniline (PANI). The different types of healing, the strategies adopted to optimize electrical and mechanical properties, and the various possible healing mechanisms are introduced. Finally, the main challenges and perspectives in the field are discussed.