MXene‐Vitrimer Nanocomposites: Photo‐Thermal Repair, Reinforcement, and Conductivity at Low Volume Fractions Through a Percolative Voronoi‐Inspired Microstructure

Abstract An innovative process to multifunctional vitrimer nanocomposites with a percolative MXene minor phase is reported, marking a significant advancement in creating stimuli‐repairable, reinforced, sustainable, and conductive nanocomposites at diminished loadings. This achievement arises from a Voronoi‐inspired biphasic morphological design via a straight‐forward three‐step process involving ambient‐condition precipitation polymerization of micron‐sized prepolymer powders, aqueous powder‐coating with 2D MXene (Ti 3 C 2 T z ), and melt‐pressing of MXene‐coated powders into crosslinked films. Due to the formation of MXene‐rich boundaries between thiourethane vitrimer domains in a pervasive low‐volume fraction conductive network, a low percolation threshold (≈0.19 vol.%) and conductive polymeric nanocomposites (≈350 S m −1 ) are achieved. The embedded MXene skeleton mechanically bolsters the vitrimer at intermediate loadings, enhancing the modulus and toughness by 300% and 50%, respectively, without mechanical detriment compared to the neat vitrimer. The vitrimer's dynamic‐covalent bonds and MXene's photo‐thermal conversion properties enable repair in minutes through short‐term thermal treatments for full macroscopic mechanical restoration or in seconds under 785 nm light for rapid localized surface repair. This versatile fabrication method to nanocoated pre‐vitrimer powders and morphologically complex nanocomposites is compatible with classic composite manufacturing, and when coupled with the material's exceptional properties, holds immense potential for revolutionizing advanced composites and inspiring next‐generation smart materials.