Stimuli-responsive polymer nanocomposites: Reversibility as a tool for advanced manufacturing of functional devices

Over the past decade, rapid developments and advancements in the electronic industry have led to a sharp increase in electronic waste (e-waste) disposed in landfills and not reusable. A wide and diversified range of advanced materials are present in e-waste. Among them, polymer nanocomposites represent a valuable example of high-added-value materials that can have however negative environmental consequences. Although thermoset polymer nanocomposites have demonstrated various beneficial properties such as high chemical resistance, and good mechanical strength, owing to their covalently crosslinked network, their potential damage could shorten the lifespan of electronic devices, increasing the amount of e-waste. To extend their service life, polymer matrices with self-healing abilities, and a good recovery of mechanical properties after healing have been developed. In this context, polymer matrices with dynamic covalent bonds activated by a thermal stimulus stand out as an attractive choice because they combine the re-processability of thermoplastics with the high mechanical performance of thermoset polymers. This chapter will discuss two emerging categories of polymer matrices with thermally reversible covalent bonds: Diels-Alder (DA)- and vitrimer-based systems. Within these two classes of dynamic polymer nanocomposites, the focus will be on the reaction mechanisms enabling self-healing, the types of nanofillers used, the recovery of mechanical and functional properties after damage, and the potential applications in devices and sensors. This work will therefore foster new studies and discussions in the field of repairable electronic and functional devices to prolong their lifetime and reduce their environmental impact.