Synergy of hyperbranched polysiloxane and MoS₂/rGO heterostructured particles for enhancing polyimide bonded solid lubricating coatings

The weak adhesion and tribological properties of polyimide (PI) restrict its practical application as bonded solid lubricating coatings in high-tech fields. Herein, a novel PI bonded solid lubricating coating was prepared using hyperbranched polysiloxane containing Si-O-C chain segments (HBPSi) and MoS₂/reduced graphene oxide (rGO) heterostructured particles. Surprisingly, the adhesion, average coefficient of friction, wear life and load carrying capacity of the PI bonded solid lubricating coating can achieve level 1, 0.03, 550 s and 3400 N, respectively. In particular, the average coefficient of friction in the stabilization stage is reduced by 91.4 % compared to the pure PI coating, which is superior to that of most reported polyimide coatings. This is attributed to the synergistic enhancement effect of “soft-hard” particles between HBPSi and MoS₂/rGO heterostructured particles. Furthermore, this work provides an important direction for the design and preparation of high-performance bonded solid lubricating coatings.