Recently, a facile and general coating technology to enhance moisture/water stability of metal-organic frameworks has been successfully developed by the collaboration of Prof. YU Shuhong and Prof. JIANG Hailong’s research groups at University of Science and Technology of China (USTC) of Chinese Academy of Sciences.

Metal-organic frameworks (MOFs), as a relatively new class of porous materials, have attracted great interest for intriguing structural topologies and potential applications as functional materials. Given that the metal-ligand coordination bonds are more or less vulnerable to water molecules, most of reported MOFs are water or even moisture sensitive.

MOFs have shown potential applications in diverse fields, but stability has being recognized as a major barrier to limit their practical applications. It is unavoidable to contact air (including moisture) during the sample handling process for almost all applications and that possibly causes the structural deterioration of MOFs.

To address this issue, researchers discovered a general and effective approach by using a facile polydimethysiloxane (PDMS)-coating treatment to form a protective hydrophobic thin layer on the surface of MOFs. The PDMS-coated MOFs exhibit highly hydrophobic behavior and excellent moisture/water tolerance as well as retained inherent porosity.  

Researchers employed three representative MOFs to investigate their water stability before and after PDMS coating to demonstrate the universality of this PDMS-coating approach. All PDMS-modified MOFs exhibited enhanced stability of the framework against degradation toward moisture/water. The PDMS-coated MOF have well retained porosity and surface area, as well as the active sites that remain accessible to substrates after water treatment. Such a facile and general strategy would open a new avenue to moisture/water-stable MOFs or MOF composites for practical applications. 

The work has been published in the Journal of the American Chemical Society (J. Am. Chem. Soc. 2014, 136, 16978-16981; DOI: 10.1021/ja509960n). Mr. ZHANG Wang and Mr. HU Yingli are co-first authors.

Paper Link: http://pubs.acs.org/doi/abs/10.1021/ja509960n 

The research project is sponsored by the National Basic Research Program of China, the National Natural Science Foundation of China, the Recruitment Program of Global Youth Experts and the Chinese Academy of Sciences. 

Figure: PDMS coating can improve the Moisture/Water Stability of MOFs. (Image by YU and ZHANG 's group)