Hydrogen-bond networks governing the mechanical stability and reconfigurability of NTO assemblies

Molecular-level understanding of the interfacial assembly and mechanical stability of energetic materials is crucial for the design of safe and robust functional coatings. Using low-temperature scanning tunneling microscopy (STM), we reveal that 3-nitro-1,2,4-triazol-5-one (NTO) molecules on Au(111) self-assemble into highly ordered one-dimensional double chains driven by cooperative O⋯H and N⋯H hydrogen bonds. Significantly, STM tip-manipulation experiments demonstrate the robust structural cohesion of these chains. They exhibit a characteristic “whip-like” elastic bending without fracture or molecular detachment, providing direct microscopic evidence for the stabilizing role of the hydrogen-bond network. Furthermore, we demonstrate a chemical modulation strategy by introducing 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) molecules. The co-assembly disrupts the continuous NTO chains, inducing a transition to localized tetrameric clusters via interfacial interactions. These findings offer atomistic insights into the robustness of NTO surface layers and provide a supramolecular strategy for tailoring the microstructure of energetic films.