Research Update: Mechanical properties of metal-organic frameworks – Influence of structure and chemical bonding

Li, Wei; Henke, Sebastian; Cheetham, Anthony K.

doi:10.1063/1.4904966

Cited by 73 publications

(69 citation statements)

References 71 publications

(43 reference statements)

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“…Whilst the chemical affinity and structural versatility of MOFs have been systematically studied and extensively characterised, 2 hitherto considerably little attention has been paid to its physical properties that are centrally important to many real-world applications. 5 Foregoing notwithstanding, it is comforting to see that there has been an increasing range of research activities evolving in the past five years devoted to the emerging area which we termed "MOF mechanics", encompassing both theoretical and experimental studies as exemplified below: not deforming excessively or collapsing under load), certain elementary data about its mechanical behaviour will be required (e.g.…”

Section: Introductionmentioning

confidence: 99%

Explaining the mechanical mechanisms of zeolitic metal–organic frameworks: revealing auxeticity and anomalous elasticity

Ryder

Tan

2016

Dalton Trans.

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The comprehensive elastic properties of Zeolitic Imidazolate Frameworks (ZIF-1 to ZIF-4) have been computed using density functional theory (DFT). We employed the periodic CRYSTAL14 code to calculate the single-crystal elastic coefficients (Cij) at the B3LYP level of theory. While the chemical compositions of ZIFs-1 to -4 are the same, each structure features a distinct network topology, crystal symmetry and porosity configuration, which translate into differential structure-function mechanical correlations. We elucidate the anisotropic mechanical response with respect to the directionally dependent Young's and shear moduli properties. Our theoretical results suggest that ZIF-3 adopting a dft topology has an extremely low shear resistance (Gmin = 0.1 GPa), which is also underpinning the flexible mechanism responsible for its negative Poisson's ratio (auxetic νmin = -0.43). Interestingly, we identified that ZIF-1, ZIF-2, and ZIF-4 could exhibit a nearly zero Poisson's ratio for certain crystal orientations, which is reminescent of a rare "cork-like" phenomenon where there is practically no lateral deformation corresponding to an applied axial strain. Furthermore, we determined the bulk moduli and linear compressibilities, alongside the averaged elastic properties of the ZIF polycrystals.

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Section: Introductionmentioning

confidence: 99%

Explaining the mechanical mechanisms of zeolitic metal–organic frameworks: revealing auxeticity and anomalous elasticity

Ryder

Tan

2016

Dalton Trans.

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“…The crystalline order between metals and ligands combined with cooperative structural transformability, forming flexible and responsive MOFs, namely soft porous frameworks. These materials can respond to mechanical stimuli in a tunable and precise fashion by molecular design, which does not exist for other known solid-state materials 25 26 . The elastic behaviour of soft porous crystals is usually complex, such as anisotropic flexibility, negative Poisson’s ration and high NLC 25 26 27 .…”

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confidence: 99%

H3O+ tetrahedron induction in large negative linear compressibility

Wang

Feng

2016

Sci Rep

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Despite the rarity, large negative linear compressibility (NLC) was observed in metal-organic framework material Zn(HO3PC4H8PO3H)∙2H2O (ZAG-4) in experiment. We find a unique NLC mechanism in ZAG-4 based on first-principle calculations. The key component to realize its large NLC is the deformation of H3O+ tetrahedron. With pressure increase, the oxygen apex approaches and then is inserted into the tetrahedron base (hydrogen triangle). The tetrahedron base subsequently expands, which results in the b axis expansion. After that, the oxygen apex penetrates the tetrahedron base and the b axis contracts. The negative and positive linear compressibility is well reproduced by the hexagonal model and ZAG-4 is the first MOFs evolving from non re-entrant to re-entrant hexagon framework with pressure increase. This gives a new approach to explore and design NLC materials.

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“…22 MOF is a class of hybrid crystalline compounds built from organic-inorganic moieties, with a vast chemical and physical tunability to suit a wide range of applications. [23][24][25] significant scientific attention due to its unique combination of properties: highly ordered intrinsic porosity and well-defined architecture, exceptionally large surface area, rich structural diversity, and facile synthesis methods. [26][27][28] The filler phase used in this study is termed ZIF-90: belonging to a subclass of MOFs known as Zeolitic Imidazole Frameworks (ZIFs), it has a sodalite network topology and a high surface area (1270 m 2 g 1 ), 29 akin to the prototypical ZIF-8 sodalite structure.…”

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confidence: 99%

Thermo-mechanical properties of mixed-matrix membranes encompassing zeolitic imidazolate framework-90 and polyvinylidine difluoride: ZIF-90/PVDF nanocomposites

et al. 2017

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Mixed-matrix membranes are contemporary nanocomposite materials with many potential applications, from liquid and gas separations to chemical sensors and biomedicine. We report fabrication of a metal-organic framework (MOF)-based nanocomposite, combining polyvinylidene difluoride (PVDF) polymer as the matrix and ZIF-90 nanocrystals of up to 30 wt. % filler content. The focus is to establish the processing—microstructure—mechanical property relationships. We reveal the importance for quantifying salient effects of the filler contents: (i) tensile strength degrades beyond 10 wt. % and (ii) mechanical toughness declines due to membrane embrittlement. These are vital mechanical aspects but widely overlooked in the emergent field of MOF membranes and composites.

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Research Update: Mechanical properties of metal-organic frameworks – Influence of structure and chemical bonding

Abstract: Thermal and mechanical stability of zeolitic imidazolate frameworks polymorphs APL Materials 2, 124110 (2014); 10.1063/1.4904818First-principles study of elastic mechanical responses to applied deformation of metal-organic frameworks

Cited by 73 publications

References 71 publications

Explaining the mechanical mechanisms of zeolitic metal–organic frameworks: revealing auxeticity and anomalous elasticity

Explaining the mechanical mechanisms of zeolitic metal–organic frameworks: revealing auxeticity and anomalous elasticity

H3O+ tetrahedron induction in large negative linear compressibility

Thermo-mechanical properties of mixed-matrix membranes encompassing zeolitic imidazolate framework-90 and polyvinylidine difluoride: ZIF-90/PVDF nanocomposites

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