Electroactive performance and cost evaluation of carbon nanotubes and carbon black as conductive fillers in self-healing shape memory polymers and other composites

Multiwalled carbon nanotubes (MWCNT) and carbon black (CB) have been widely used as conductive fillers in electroactive polymer composites. MWCNT-based composites generally have lower resistivity and percolation thresholds, while CB-based ones are considerably cheaper. To balance these pros and cons, ternary composites (TCs) (polymer-MWCNT-CB) can be formulated. Here, we prepared electroactive MWCNT-CB TCs capable of self-healing and with shape memory properties, based on polyketones reversibly-crosslinked via Diels-Alder chemistry. Unexpectedly, the cheaper CB-rich formulations had lower resistivities, thus better electroactive self-healing and shape memory responses. Nonetheless, not all electroactive MWCNT-CB TCs have this clear cost-effectiveness. We evaluated the cost-performance of multiple reported MWCNT-CB TCs systems and found different general trends (positive, negative, and synergistic cost-efficiency relationships). Thus, the cost-effectiveness of these fillers (and their combination) greatly depends on each composite system and what it is intended for. This work includes the first systematic report on cost-performance of MWCNT and CB as conductive fillers.