A research team at Northwestern University in the US has developed a method of coating textiles with zirconium-based metal-organic frameworks (MOFs) that are able to capture and neutralise potentially harmful chemical agents faster than existing technologies. The composite material has therefore been tipped for a host of applications, namely for integration within the PPE donned by military professionals.
MOFs are periodic nanoporous crystalline frameworks made from metal ions or clusters coordinated to organic ligands. The porosity of these structures enables a high degree of absorption and adsorption, making them idyllic for this concept of capturing chemical agents. Research, led by Omar Farha, has established that the MOFs are able to continuously degrade chemicals when absorbed through the catalysis reaction.
Although the chemical degradation reaction requires water, the researchers say the nanopores in the MOFs can supply the needed water by absorbing it from ambient humidity. This makes it easier to deploy filters and other anti-nerve agent equipment based on this material, the researcher explains.
During testing it was a chemical formula based on zirconium (Zr) that proved to show the greatest efficacy. The team, after first applying the textile coating and allowing it to dry overnight, exposed the material to the nerve agent DMNP to assess how it reacted. Results are said to have shown that the composite material is effective in degrading the potency of the chemical, in turn reducing the potential threat it would pose to human health.
The coating’s durability is also said to have stood up during testing. It’s reported that the coating securely adheres to the cotton even when immersed in water and agitated. The composite’s catalytic activity also remains high after being exposed to ambient air for 100 days. In a final series of tests, the team found the material retains its catalytic activity when exposed to atmospheric carbon dioxide and sweat – lending itself to apparel applications.