Macromolecularly Engineered Thermoreversible Heterogeneous Self‐Healable Networks Encapsulating Reactive Multidentate Block Copolymer‐Stabilized Carbon Nanotubes

Abstract

The development of heterogeneous covalent adaptable networks (CANs) embedded with carbon nanotubes (CNTs) that undergo reversible dissociation/recombination through thermoreversibility has been significantly explored. However, the carbon nanotube (CNT)‐incorporation methods based on physical mixing and chemical modification could result in either phase separation due to structural incompatibility or degrading conjugation due to a disruption of π‐network, thus lowering their intrinsic charge transport properties. To address this issue, the versatility of a macromolecular engineering approach through thermoreversibility by physical modification of CNT surfaces with reactive multidentate block copolymers (rMDBCs) is demonstrated. The formed CNTs stabilized with rMDBCs (termed rMDBC/CNT colloids) bearing reactive furfuryl groups is functioned as a multicrosslinker that reacts with a polymaleimide to fabricate robust heterogeneous polyurethane (PU) networks crosslinked through dynamic Diels‐Alder (DA)/retro‐DA chemistry. Promisingly, the fabricated PU network gels in which CNTs through rMDBC covalently embedded are flexible and robust to be bendable as well as exhibit self‐healing elasticity and enhanced conductivity.

Carbon Nanotube Composites with Bottlebrush Elastomers for Compliant Electrodes

“…Dynamic polyester–CNT composites of similar filler loading (0.25 wt % CNT) but prepared with a linear polymer reportedly have a shear modulus ∼70 MPa, nearly 3 orders of magnitude stiffer than the composites described here . Notably, a recent report achieved a dynamic composite with a similar modulus to our materials (0.5 wt % CNT, 64 kPa) but only after 70 wt % plasticizer was added . We caution that directly comparing the modulus of different composites can be problematic, as it is highly dependent on both the dispersion process and polymer matrix chemistry. , Nevertheless, our bottlebrush composites are significantly softer than others reported in the literature.…”

“… 42 Notably, a recent report achieved a dynamic composite with a similar modulus to our materials (0.5 wt % CNT, 64 kPa) but only after 70 wt % plasticizer was added. 43 We caution that directly comparing the modulus of different composites can be problematic, as it is highly dependent on both the dispersion process and polymer matrix chemistry. 14 , 39 Nevertheless, our bottlebrush composites are significantly softer than others reported in the literature.…”

Recent advances in self-healing polyurethane based on dynamic covalent bonds combined with other self-healing methods

“…Both have good dispersion and Young's modulus and strain at break of these materials are enhanced. 92–94…”

“…Both have good dispersion and Young's modulus and strain at break of these materials are enhanced. [92][93][94] Rong Sun et al synthesized a new self-healing composite composed of functionalized graphene nanosheets and PU. 95 They reduced water-amine-functionalized graphene oxide to obtain water-amine-functionalized graphene nanosheets, namely, hydroxylated graphene nanosheets (FGN).…”

Dynamic poly(hindered urea) hybrid network materials crosslinked with reactive methacrylate polymer

“…21,22 HUB undergoes dynamic exchange reaction at relatively low temperature, compared with Diels-Alder cycloadduct commonly implemented at >120 °C. 23,24 Furthermore, HUB is formed by the reaction of an isocyanate with a bulky amine (mostly secondary amine) and easily integrated in polyurethanes and polyureas, both of which are commercially important classes of polymeric materials. Since the first report, 22 several strategies have been explored to fabricate effective CANs based on HUBs bearing t-butylamino groups through step-growth polyaddition.…”