High wear/ corrosion resistance of PI coating: Exploration via interfaces, bonding and structure

Abstract

This study discusses the enhancement mechanism of Ti₃C₂T_x MXene on the wear/ corrosion resistance of polyimide (PI) coatings from the perspectives of interface interaction, bonding and filler structure. Despite the excellent performance of Ti₃C₂T_x MXene, its challenges in forming strong interface and strong bonding in PI limit its protection efficiency. To address this, we innovatively prepared amino-functionalized Ti₃C₂T_x nanoflowers (Ti₃C₂T_x@PEI) and uniformly dispersed them in the PI matrix as an enhancer. The results show that Ti₃C₂T_x@PEI achieves optimal protection of PI (PMX-PI composite coating). Under high load, the wear rate of PMX-PI composite coating is only 6.23×10^-5 mm³ N^-1 m^-1. After 4-week immersion test, it keeps the highest |Z|_0.01Hz value of 3.73 × 10⁷ Ω·cm² about two orders of magnitude higher than that of PI. And the R_c is 1.81×10⁶ Ω·cm² about 2.2 times higher than that of PI (8.07×10⁵ Ω·cm²). Based on Materials Studio (MS) calculations, Ti₃C₂T_x@PEI exhibits the highest affinity with PI-Precursor (PAA), showing an interaction energy of -21.41 kcal/mol. Additionally, the -NH₂ groups in Ti₃C₂T_x@PEI are effectively utilized to form -CON- groups through dehydration condensation with -COOH groups in PAA at high temperature. These strong interactions and bonds promote uniform dispersion, filling PI’s structural defects.