Smart Coating Provides Protective Function in Fabrics

Smart Coating Transforms Fabric into Protective Equipment Smart Coating Converts Fabric into Protective Gear According to recent research, a durable copper-based coating developed by Dartmouth College researchers can be fully integrated into fabric to create reusable and stimulus-responsive materials such as protective equipment, environmental sensors and smart filters. As noted by the research team in the Journal of the American Chemical Society (JACS), the coating responds to the presence of toxic gases in the air by converting them into less toxic substances trapped within the fabric. The findings are based on conductive metal-organic framework technology developed in the laboratory of Katherine Mirica, responsible author and chemistry professor at Dartmouth. The technique, first reported in JACS in 2017, was a simple coating that could be layered onto cotton and polyester to create smart fabrics that the researchers named SOFT—Self-Organized Framework on Textiles. Work conducted demonstrated that SOFT smart fabrics could detect and capture toxic substances in the environment. For the new study, researchers found that by using a copper precursor—rather than the simple coating reported in 2017—they could fully embed the framework into fabrics, allowing them to design specific patterns and more effectively fill gaps between fibers and threads. Researchers found that the framework technology effectively converted the toxin nitric oxide into nitrite and nitrate, and transformed the toxic, flammable gas hydrogen sulfide into copper sulfide, while noting that the technology withstands standard washing as well as tearing and abrasion. Mirica said the versatility and durability provided by the new method would enable the framework to be applied for specific uses such as a sensor on protective clothing or as a filter in a particular environment. "This new deposition method means that electronic textiles could potentially interface with a much broader range of systems because they are very robust. This technological advance opens the way for applying the framework's combined filtering and sensing capabilities that could be valuable in biomedical environments and environmental remediation." Mirica said the technique developed could be a low-cost alternative to technologies that require an energy source or—like catalytic converters in automobiles—rely on rare metals, making them costly and difficult to apply. "Here, we rely on a material that is abundant in the world to detoxify poisonous chemicals and we do it without any external energy input, so we don't need high temperatures or electrical current to perform this function," Mirica said. Mirica noted that Michael Ko, first and co-author of the paper, earned his doctoral degree in chemistry from Dartmouth in 2020 and first observed the new process in 2018 when trying to deposit the metal-organic framework onto thin film copper-based electrodes. However, later the framework would replace the copper electrodes. "Michael wanted the metal-organic framework to be on top of the electrodes, not to replace them. It took us four years to understand what was happening and why it was beneficial. It is a very simple process, but the chemistry behind it is not. It took us some time to understand it and required additional involvement from students and researchers." Mirica said the team discovered that the metal-organic framework "grew" on copper and that instead they had placed a material with the ability to filter and convert toxic gases. Ko and co-author Lukasz Mendecki, as postdoctoral researchers in the Mirica Group during 2017-18, investigated methods for applying the framework material to fabric in specific designs and patterns. Aileen Eagleton, first and co-author of the paper and a master's student in the Mirica Group, completed the work by optimizing the process of printing the metal-organic framework onto fabric as well as determining how the structure and properties of the technique were affected by chemical exposure and reaction conditions. Mirica noted that future work would focus on developing new multifunctional framework materials and scaling up the process of embedding metal-organic coatings into fabric. Aileen M. Eagleton, Michael Ko, Robert M. Stolz, Nataliia Vereshchuk, Zheng Meng, Lukasz Mendecki, Adelaide M. Levenson, Connie Huang, Katherine C. MacVeagh, Akbar Mahdavi-Shakib, John J. Mahle, Gregory W. Peterson, Brian G. Frederick, Katherine A. Mirica. Fabrication of Multifunctional Electronic Textiles Using Oxidative Restructuring of Copper into a Cu-Based Metal–Organic Framework. Journal of the American Chemical Society, 2022; 144 (51): 23297 DOI: 10.1021/jacs.2c05510 Source