Effect of Atomic Force Microscopy Sliding-Contact Load on Graphene–Perfluorophenyl Azide Nanosurface Wear for Friction Decay Measurements and Mechanochemical Reaction Kinetics Analysis

High Resolution Image Download MS PowerPoint Slide Understanding the atomic wear mechanisms governing nanoscopic solid–solid sliding contacts in functionalized graphene–polymer coating materials is essential for designing mechanically robust surfaces. Here, we investigate how AFM tip normal contact load, under a constant sliding velocity, regulates frictional decay and mechanochemical reaction kinetics on PFPA-functionalized single-layer graphene. Friction–time measurements show a load-dependent exponential decrease in relative friction, indicating that increased mechanical load input accelerates surface bonding dissociations. A reaction-rate analysis model reveals that higher contact stresses enhance the mechanochemical kinetics of C–N bond dissociation by lowering the activation barrier. A unified mechanism is proposed in which AFM-induced C–N bond cleavage enables subsequent azide (−N═N═N) substitution, progressively modifying interfacial chemistry and reducing friction. These results demonstrate that tribologically driven mechanochemical reactions dominate the atomic wear of graphene–PFPA surfaces, establishing normal load as a key regulator of reaction pathways and frictional behavior. The findings provide fundamental insight into mechanochemical wear processes and offer guidelines for engineering durable, load-responsive nanoscale interfaces.