Effects of Nanoscale Heterogeneities on the Reactivity of Shocked Erythritol Tetranitrate

The mechanochemical effects of 5 nm spherical heterogeneities on the reactivity of shocked crystalline erythritol tetranitrate (ETN), an emerging improvised explosive, are revealed for the first time. Reactive molecular dynamics simulations in conjunction with the symmetric plate-impact technique, are employed to characterize different stages of the process, including shock–void interaction, void collapse, enhanced reactivity, and subsequent molecular decomposition. The formation of supersonic nanojets from the proximal void surface is observed to greatly enhance local heating following impact of the nanojets on the distant void surface. It is demonstrated that the nanovoid collapse closely matches a Rayleigh-type hydrodynamic bubble collapse, including a spherical-to-crescent shape transformation. The chemical decomposition mechanism of condensed phase ETN is analyzed and is shown to follow a unimolecular path. The molecular decomposition of a defect containing crystal occurs with significantly higher rates compared to the perfect crystal.