A facile and general coating approach to moisture/water-resistant metal-organic frameworks with intact porosity

The moisture sensitivity of many metal-organic frameworks (MOFs) poses a critical issue for their large-scale real application. One of the most effective methods to solve this problem is to convert the surface of MOFs from hydrophilic to hydrophobic. Herein, we develop a general strategy to modify hydrophobic polydimethysiloxane (PDMS) on the surface of MOF materials to significantly enhance their moisture or water resistance by a facile vapor deposition technique. MOF-5, HKUST-1, and ZnBT as representative vulnerable MOFs were successfully coated by PDMS, and these coated samples well inherited their original crystalline nature and pore characteristics. Strikingly, the surface areas of these MOFs were nearly 100% retained upon PDMS-coating. Such a coating process might render MOFs applicable in the presence of water or humidity in extended fields such as gas sorption and catalysis.