Mechanical properties of metal-organic frameworks.

Louis R Redfern,Omar K Farha

doi:10.1039/c9sc04249k

Abstract

As the field of metal-organic frameworks (MOFs) continues to grow, the physical stability and mechanical properties of these porous materials has become a topic of great interest. While strategies for synthesizing MOFs with desirable chemical functionalities or pore sizes have been established over the past twenty years, design principles to modulate the response of MOFs to mechanical stress are still underdeveloped. The inherent porosity of these frameworks results in many interesting and sometimes unexpected phenomena upon exposure to elevated pressures and other physical stimuli. Beyond its fundamental importance, an understanding of mechanical properties (e.g. bulk modulus, shear modulus, Young's modulus, linear compressibility, and Poisson's ratio) plays an essential role in the post-synthetic processing of MOFs, which has implications in the successful transition of these materials from academic interest to industrial relevance. This perspective provides a concise overview of the efforts to understand the mechanical properties of MOFs through experimental and computational methods. Additionally, current limitations and possible future directions for the field are also discussed briefly.

Highlights

Metal–organic frameworks (MOFs) are a class of porous, crystalline materials comprised of inorganic nodes joined by organic linkers
Over the past twenty years, these highly functional materials have garnered much attention, with tremendous efforts put into the synthesis, characterization, and post-synthetic modi cation of these scaffolds; the study of the mechanical properties of metal–organic frameworks (MOFs) (e.g. Young's modulus, shear modulus, bulk modulus, Poisson's ratio, and linear compressibility) is comparatively in its nascency
This study indicates that Zeolitic imidazolate frameworks (ZIFs)-4 displays similar shear-mode so ening, suggesting that this mechanism of amorphization may be generalizable to other ZIFs and MOFs

Summary

Introduction

Metal–organic frameworks (MOFs) are a class of porous, crystalline materials comprised of inorganic nodes joined by organic linkers. These components assemble into two- and three-dimensional networks with promising applications in International Institute of Nanotechnology, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA. E-mail: o-farha@ northwestern.edu a wide range of areas, including gas storage,[1] catalysis,[2] chemical separations,[3] and drug delivery.[4] Over the past twenty years, these highly functional materials have garnered much attention, with tremendous efforts put into the synthesis, characterization, and post-synthetic modi cation of these scaffolds; the study of the mechanical properties of MOFs (e.g. Young's modulus, shear modulus, bulk modulus, Poisson's ratio, and linear compressibility) is comparatively in its nascency.

Objectives

Methods

Findings

Conclusion