Honeycomb-inspired polyimide coatings via KH-570 self-assembly toward high-performance corrosion & wear resistance

Hierarchical honeycomb-like polyimide (PI) composite coatings are engineered via humidity-regulated KH570 hydrolysis and high-temperature self-assembly. Controlled hydrolysis of KH570 generates uniform microspheres during thermal curing, while concurrent poly (amic acid) (PAA) imidization enables in situ microspheres encapsulation, yielding compact honeycomb-structured KH-PI composites. To mitigate the brittleness caused by the KH-PI matrix and microspheres phase separation without compromising structural integrity, Ti 3 C 2 T x MXene nanosheets are incorporated into the precursor system (forming KMX-PI). Hydrogen bonding and van der Waals interactions between Ti 3 C 2 T x MXene surface functional groups and PI chains mediate interfacial toughening, synergistically enhancing mechanical and environmental tolerance. Comprehensive characterization confirms that KMX-PI retains KH-PI's structural merits, while exhibiting superior hardness (258.0 MPa) and Young's modulus (293.47 GPa). After 4-week soaking, KMX-PI achieves an electrochemical impedance modulus (|Z| 0.01Hz ) of 1.17 × 10 9  Ω·cm 2 and reduced wear rates (1.56 × 10 −5  mm 3 ·N −1 ·m −1 ). Wear resistance arises from KH570 microspheres' rolling-sliding synergy effect and Ti 3 C 2 T x MXene's lubricating film. Corrosion resistance stems from: (i) curved pore walls delaying diffusion, (ii) microsphere barriers, and (iii) Ti 3 C 2 T x 's nanoscale labyrinth effect. This multiscale design integrates mechanical robustness and environmental resistance of polymer coatings for extreme conditions.