A nano-engineered hierarchical composite with localized toughening and integrated damage sensing capabilities is described. Thermoplastic phenoxy interleaves which dissolve in epoxy resin upon heating and subsequently phase separate upon curing were employed as carrier films for localized deposition of carbon nanotubes in carbon fibre–reinforced plastics, avoiding filtration of carbon nanotubes during liquid resin infusion. Interlaminar fracture toughness was improved compared to reference epoxy-based laminates, while the introduced carbon nanotube network was utilized for in situ damage sensing purposes. Using this technology based on dissolvable thermoplastic carrier films, nanofillers can be easily introduced into fibre-reinforced composites at desired regions while simultaneously avoiding typical nanofiller drawbacks such as filtering or increased resin viscosity.
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