Metal-organic frameworks (MOFs) are a class of porous materials constructed from metal nodes and organic linkers. Unfortunately, many MOFs are moisture-sensitive and unstable in aqueous solution, which limits their practical application. Most methods for improving water stability, however, are time-consuming and complicated.

Hsi-Ya Huang and colleagues, Chung Yuan Christian University, Taiwan, have developed an approach for enhancing the water stability of MOFs by incorporating them into polymer monoliths through microwave-assisted polymerization. The team encapsulated the water-sensitive MOFs DUT-4, DUT-5, CYCU-3, and HKUST-1 in poly(BMA-EDMA) (BMA = butyl methacrylate, EDMA = ethylene dimethacrylate). The method is effective in retaining the intrinsic performance of the MOF.

The presence of a hydrophobic polymer skeleton significantly enhances the water stability of the MOF. The crystalline structure of the MOF could be retained by choosing narrow polymer columns for embedding. The team demonstrated the applicability of MOF-polymer monoliths as an absorbent for the solid-phase microextraction of nine different non-steroidal anti-inflammatory drugs. The composite could be reused for extraction over 30 times.

• A Simple Approach to Enhance the Water Stability of a Metal-Organic Framework,
  Yung-Han Shih, Yu-Ching Kuo, Stephen Lirio, Kun-Yun Wang, Chia-Her Lin, Hsi-Ya Huang,
  Chem. Eur. J. 2016.
  DOI: 10.1002/chem.201603647