Thermally Switchable Electrically Conductive Thermoset rGO/PK Self-Healing Composites

Abstract

Among smart materials, self-healing is one of the most studied properties. A self-healing polymer can repair the cracks that occurred in the structure of the material. Polyketones, which are high-performance thermoplastic polymers, are a suitable material for a self-healing mechanism: a furanic pendant moiety can be introduced into the backbone and used as a diene for a temperature reversible Diels-Alder reaction with bismaleimide. The Diels-Alder adduct is formed at around 50 °C and broken at about 120 °C, giving an intrinsic, stimuli-responsive self-healing material triggered by temperature variations. Also, reduced graphene oxide (rGO) is added to the polymer matrix (1.6–7 wt%), giving a reversible OFF-ON electrically conductive polymer network. Remarkably, the electrical conductivity is activated when reaching temperatures higher than 100 °C, thus suggesting applications as electronic switches based on self-healing soft devices.

Rapid self-healing in IR-responsive plasmonic indium tin oxide/polyketone nanocomposites

“…The thermal properties of the nanocomposites were studied by means of differential Scanning Calorimetry (DSC, TA Instruments, New Castle, DE, USA) and thermogravimetric analysis (TA DSC250) under N 2 as described in previous studies. 34 UV-vis-NIR spectrophotometric measurements on the nanocomposite lms were performed by using a Cary 5000 UVvis-NIR spectrophotometer.…”

“…31,32 In this framework, we have efficiently prepared self-healing thermoreversible polymeric networks by modifying polyketones with furan groups that undergo thermally reversible Diels-Alder reaction with maleimide compounds. 28,33,34 According to the Wool and O'Connor model, 35 a self-healing process includes surface molecule arrangement, surface contact, chain inter-diffusion and randomization (entanglement), and chemical interaction. Moreover, local and temporary polymeric mobility should be accomplished to achieve an efficient self-healing performance without affecting the material's structure and functionality.…”

“…However, these materials are expensive, difficult to disperse in the polymer matrix, and negatively affect the optical transparency of polymer lms. 34,47 Among the mentioned materials, Au and Ag nanostructures are promising candidates, due to their ability to act as an efficient nano-source of heat when they are irradiated at their plasmonic resonance. [48][49][50] However, they are rather expensive and generally involve irradiation with visible or short wavelength NIR light (600-1000 nm), which can be signicantly absorbed or scattered by the polyketone matrix.…”

“…1). 34 Moreover, Sn-doped indium oxide (ITO) nanocrystals (NCs) were used as an infrared photothermal source owing to their outstanding plasmonic properties and visible transparency as determined by UV-vis-NIR spectroscopy. Their morphology was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD), whereas the Sn doping level was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).…”

NIR Light Stimulated Self‐Healing Reduced Tungsten Oxide/Polyurethane Nanocomposite Based on the Diels−Alder Reaction

“…They are now being introduced into materials with high T g , such as epoxy resins, polyamides, crosslinked polyesters, etc. [ 27–30 ] In these materials, the DA bond forms a crosslinked network that improves the mechanical properties. DA shows good self‐healing properties even for materials with T g greater than 100 °C because the reaction initiation temperature of retro DA is still higher than T g .…”