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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 (Ti₃C₂T_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. 

Abstract When a few drops of acid (hydrochloric, acrylic, propionic, acetic, or formic) are added to a colloid comprised of 1D lepidocrocite titanate nanofilaments (1DLs)–2 × 2 TiO₆octahedra in cross‐section–a hydrogel forms, in many cases, within seconds. The 1DL synthesis process requires the reaction between titanium diboride with tetramethylammonium (TMA⁺), hydroxide. Using quantitative nuclear magnetic resonance (qNMR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), the mass percent of TMA⁺after synthesis is determined to be ≈ 13.1 ± 0.1%. The TMA⁺is completely removed from the gels after 2 water soak cycles, resulting in the first completely inorganic, TiO₂‐based hydrogels. Ion exchanging the TMA⁺with hydronium results in gels with relatively strong hydrogen bonds. The hydrogels' compression strengths increased linearly with 1DL colloid concentration. At a 1DL concentration of 45 g L⁻¹, the compressive strength, at 80% deformation when acrylic acid is used, is ≈325 kPa. The strengths are ≈ 50% greater after the TMA⁺is removed. The removal of all residual organic components in the hydrogels, including TMA⁺, is confirmed by qNMR, Fourier‐transformed infrared spectroscopy (FTIR), and TGA/DSC. The 1DL phase is retained after gelation, TMA⁺removal, and 80% compression.