Anisotropic initial reaction mechanism and sensitivity characterization of the host-guest structure CL-20/H2O2 under shock loading

Y Sha and XB Zhang, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 27, 5186-5197 (2025).

DOI: 10.1039/d4cp04681a

Molecular-level interaction control and host-guest strategies are widely employed to design safer, high-performance energetic materials. This paper explores the anisotropic physicochemical response of the CL-20/H2O2 host-guest structure under impact along the (1 0 0), (0 1 0), and (0 0 1) crystallographic directions using reactive molecular dynamics simulations combined with the multiscale shock technique. The embedding of H2O2 in the CL-20 crystal cavity introduces pronounced anisotropy, driven by molecular packing differences across orientations. Elastic property analysis indicates that CL-20/H2O2 is more deformable, with a higher Poisson's ratio compared to anhydrous alpha-CL-20, but retains a brittle nature. This brittleness, combined with localized strain under shock, contributes to shear band formation, energy concentration, and hotspot generation, increasing sensitivity risks. Mechanochemically, initial decomposition is driven by N-NO2 bond homolysis and C-N bond breakage, leading to cage structure collapse. The inclusion of H2O2 strengthens molecular interactions and enhances energy localization, amplifying anisotropic decomposition pathways. This study highlights the critical role of host-guest interactions in governing anisotropic decomposition and sensitivity in energetic materials, offering valuable insights for designing safer and more stable energetic materials with optimized performance.

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