Liquid gallium has been used to produce an antiviral and antimicrobial coating by an international research team. The coating has been tested on a variety of fabrics, such as face masks.
The coating binds more strongly to tissue than some traditional metal coatings and kills 99% of various common pathogens within 5 minutes.
Germs can survive for a long time on fabrics that hospitals use for bedding, clothing, and face masks. Metal surface coatings such as copper or silver are an effective way to eradicate these pathogens, but many metal particle coating technologies have issues such as non-uniformity, processing complexity, or poor grip.
Michael Dickey, co-corresponding author of the study and Professor of Chemical and Biomolecular Engineering Camille & Henry Dreyfus, North Carolina State University
Dickey and the team at NC State, Sungkyunkwan University (SKKU) in Korea, and RMIT University in Australia set out to create a simple and cost-effective method of depositing metallic coatings on fabrics.
Initially, researchers added liquid gallium (Ga) to an ethanol solution and used sound waves to create Ga nanoparticles. This process is called sonication. The solution of nanoparticles was then applied by spraying on the fabric and Ga bound to the fibers during the evaporation of the ethanol.
The researchers then immersed the Ga-coated tissue in a solution of copper sulfate, which led to the immediate galvanic replacement reaction. The reaction tends to deposit copper on the fabric, producing a coating of nanoparticles of copper alloy and liquid metal.
The researchers verified the antimicrobial characteristics of the coated fabrics by exposing the fabric to three common microbes, namely, Staphylococcus aureus, Escherichia coli and Candida albicans.
Germs tend to grow heavily on uncoated fabrics. Eventually 99% of the pathogens were killed within 5 minutes by the copper alloy coated fabric. This was remarkably more efficient compared to control samples with copper only.
The researchers teamed up with Elisa Crisci, assistant professor of virology at NC State, and Frank Scholle, associate professor of biological sciences at NC State, to demonstrate that the coatings also repel viruses. The coating has also been tested against human influenza (H1N1) and coronavirus (HCoV 229E), which belong to the same family as SARS-CoV-2. These viruses were killed 5 minutes after the coating was applied.
Our tests indicate that these liquid metal and copper coated fabrics exhibit superior antimicrobial performance compared to other copper coated surfaces and two commercial antimicrobial masks which rely on copper and silver respectively..
Vi Khanh Truong, Vice-Chancellor’s Postdoctoral Fellow, RMIT University
Vi Khanh Truong is also a Fulbright Visiting Fellow at RMIT University and co-author of the study. According to Yoon Kwon, postdoctoral associate at SKKU and the study’s first author, “This is a better method for generating metallic coatings of fabrics, especially for antimicrobial applications, both in terms of adhesion and antimicrobial performance.. “
It could also work with metals other than copper, like silver. It is also a simple method, which should be relatively easy to scale for mass production..
Tae-il Kim, Study Co-Correspondent Author and Professor, Sungkyunkwan University
Kwon, Kentucky, et al. (2021) A liquid metal mediated metallic coating for antimicrobial and antiviral fabrics. Advanced materials. doi.org/10.1002/adma.202104298.