The effect of temperature on the mechanical properties of metal organic framework HKUST-1

This study employs molecular dynamics simulations to reveal that temperature influences the mechanical properties of HKUST – 1. • Identified three-stage stretching behavior of HKUST-1 under thermal response. • All mechanical parameters of HKUST-1 decrease with rising temperature. • High-stress atoms concentrated around Cu-centered H3BTC linkers. • Young’s modulus maximum along < 111>, minimum in < 001 > direction. • Shear modulus shows broader maximum distribution range than Young’s modulus. Elucidating the mechanical behavior of HKUST-1 under thermal response is essential for its practical applications, yet remains incompletely explored. This study employed molecular dynamics simulations to investigate the mechanical properties of HKUST-1 in response to temperature changes. The tensile process of HKUST-1 involves three distinct stages: elastic deformation, plastic deformation dominated by pore collapse and bond rupture, and fracture. While HKUST-1 exhibits flexibility, its wear and scratch resistance is weak. Elevated temperatures consistently reduce all mechanical properties of HKUST-1, including ultimate tensile strength. Under thermal stress, the HKUST-1 framework undergoes progressive degradation, where higher temperatures intensify interatomic stresses, ultimately collapsing its porous architecture. Besides, the atoms experiencing high stress are primarily located around the H 3 BTC organic linker centered on Cu. The maximum Young’s modulus of HKUST-1 is observed along the < 111 > crystallographic direction, whereas the minimum occurs along the < 001 > orientation. The shear modulus exhibits its maximum value between the < 001 > and < 011 > directions, displaying a broader distribution range of maximum compared with the Young’s modulus. This study provides insights into the mechanical mechanisms of HKUST-1 under thermal stress by analyzing parameter evolution and microscale stress distributions. The obtained results provide numerical predictions for its engineering applications in different temperatures.