Mechanical Robustness and Conductivity Retention in Ti ₃ C ₂ MXene-Enhanced Electrodes on Flexible Substrates

This study investigates Ti₃C₂T _x MXene thin film coatings that were made onto five flexible substrates, namely PET, PEN, ITO-PET, ITO-PEN, and PI, over thicknesses ranging from 5 to 100 nm. The coatings were evaluated in terms of sheet resistance before and after 500 bending cycles, optical transmittance in the UV-visible range, and the thermal and rheological properties of the MXene ink. The substrates were exposed to UV-Ozone to modify their surface wettability in order to control the nucleation of MXene film formation. The data show that MXene significantly enhances and stabilizes the conductivity of brittle ITO electrodes under bending by forming continuous pathways that bridge cracks in the fractured ITO layer, whereas uncoated ITO-PET suffers a severe loss of conductivity after deformation. Among the tested systems, a 100 nm MXene layer on ITO-PEN offers the lowest sheet resistance while maintaining useful transparency, making it a strong candidate for flexible electrodes. A 30 nm MXene coating on PET, however, exhibits the best mechanical reliability, with only a minor change in resistance after repeated bending, indicating a favorable balance between network percolation and strain tolerance. Results on PEN and PI emphasize how substrate chemistry and UV-ozone-induced hydrophilicity influence MXene nucleation, film continuity, and long-term electro-mechanical stability. The low-viscosity MXene ink and its moderate thermal conductivity further support its use in scalable slot-die processing and applications that benefit from localized Joule heating. The impact of substrate selection, surface preparation, and film thickness on the performance of MXene-based flexible conductors was studied thoroughly and provides valuable insights for designing robust, optically adjustable, and manufacturable devices.