IR-Responsive Plasmonic Indium Tin Oxide/Polyketone Nanocomposites with Fast Self-Healing Features

Materials endowed with (very) fast self-healing are highly demanded to get rid of polymer pollution and enhance the materials service life. On this account, in this contribution, nanocomposites with rapid self-healing thermo-responsive characteristics were proposed and based on the homogeneously dispersed indium tin oxide (ITO) nanocrystals (NCs). ITO NCs were used as an infrared photothermal source due to to their remarkable near-infrared (NIR) plasmonic properties and visible transparency. A furan grafted polyketone (PKFU) was utilized as supporting polymer matrix and obtained by the Paal-knorr functionalization of PK and crosslinked via the Diels-Alder (DA) reaction of an aromatic bismaleimide. Nanocomposites containing the 0.4−1.5 wt% of ITO NCs showed strong NIR absorption and, once exposed to IR irradiation, displayed fast heating (30 seconds) up to temperatures higher than 160 °C and superior to 60 °C gathered by the bare PKFU. The addition of ITO NCs did not affect the thermal behaviour of the matrix with the retro-Diels-Alder onset at 95 °C and the softening point at 50 °C that triggered the healing process. It was worth noting that the nanocomposite containing the 0.9 wt% of ITO NCs displayed the fastest healing rate that occurred after 1 second of IR irradiation, i.e. significantly faster than 50 seconds required for the bare crosslinked PKFU.