Researchers used liquid gallium to create an antiviral and antimicrobial coating and tested it on a range of fabrics including facemasks. The coating adhered more strongly to fabric than some conventional metal coatings and eradicated 99 percent of several common pathogens within five minutes. Metallic surface coatings, such as copper or silver, are an effective way to eradicate pathogens but many metal particle coating technologies have issues such as non-uniformity, processing complexity, or poor adhesion.
The team developed a simple, cost-effective way to deposit metal coatings on fabric. First, they placed liquid gallium (Ga) into an ethanol solution and used sound waves — a process known as sonication — to create Ga nanoparticles. The nanoparticle solution was then spray-coated onto the fabric and the Ga adhered to the fibers as the ethanol evaporated. The researchers dipped the Ga-coated fabric into a copper sulfate solution, creating a spontaneous galvanic replacement reaction. The reaction deposits copper onto the fabric, creating a coating of liquid metal copper alloy nanoparticles.
To test the coated fabric’s antimicrobial properties, the team exposed the fabric to three common microbes: Staphylococcus aureus, Escherichia coli, and Candida albicans — all of which grow aggressively on noncoated fabrics. The copper alloy-coated fabric eradicated over 99 percent of the pathogens within five minutes, which was significantly more effective than control samples coated with only copper.
Further tests indicate that the liquid metal copper-coated fabrics demonstrate superior antimicrobial performance compared to other copper-coated surfaces and two commercial antimicrobial facemasks that rely on copper and silver, respectively.
The method could also work with metals other than copper, such as silver. It is also a simple method, which should be relatively straightforward to scale up for mass production.