[Image above] Researchers at Lawrence Livermore National Laboratory are developing a material for protective military uniforms that is highly breathable yet protects from biological and chemical threats. Credit: LLNL; YouTube
Anyone who deals with the potential hazards of biological or chemical exposure while on the job relies on the right protective clothing to effectively shield them from the harmful elements. This is especially true for soldiers out in unfamiliar territory.
Materials used to create such protective uniforms need to withstand significant wear-and-tear and provide lasting comfort and breathability.
So advances in durable, next-generation textiles continue to make news. Earlier this year, researchers from RMIT University in Melbourne, Australia, developed nano-enhanced textiles that clean themselves with light.
Last year, Japanese company Spiber partnered with high-performance sportswear outfitter North Face to create a parka made from genetically engineered spider silk fiber—a material known for its superior strength, flexibility, and toughness, but one that has been historically challenging to scale for commercial viability.
Most recently, a team of scientists at Lawrence Livermore National Laboratory in Livermore, Calif., is developing a material for protective military uniforms that is highly breathable yet protects from biological and chemical threats.
“This material is the first key component of futuristic smart uniforms that also will respond to and protect from environmental chemical hazards,” according to an LLNL press release.
The lightweight/breathability factor for these types of uniforms is especially important to help prevent overheating and exhaustion for military personnel while working in contaminated environments. So the LLNL team fabricated “flexible polymeric membranes with aligned carbon nanotube channels as moisture conductive pores,” the release explains. “The size of these pores (less than 5 nm) is 5,000 times smaller than the width of a human hair.”
The material’s high breathability is thanks to the unique transport properties of carbon nanotube pores.
“By quantifying the membrane permeability to water vapor, the team found for the first time that, when a concentration gradient is used as a driving force, carbon nanotube nanochannels can sustain gas-transport rates exceeding that of a well-known diffusion theory by more than one order of magnitude,” according to the release.
And the extremely small pore size—less than 5 nm wide—provides protection from biological agents that are typically much larger. “Biological threats like bacteria or viruses are much larger and typically more than 10 nm in size,” the release explains. When the team put the material through filtration tests, they found that the carbon nanotube membranes effectively repelled Dengue virus.
But chemical agents are much smaller in size than biological ones. To address this issue, the team encoded the membrane pores to be able to block chemical threats, too.
“The material will be like a smart second skin that responds to the environment,” Kuang Jen Wu, leader of LLNL’s Biosecurity and Biosciences Group, says in the release. “In this way, the fabric will be able to block chemical agents such as sulfur mustard (blister agent), GD and VX nerve agents, toxins such as staphylococcal enterotoxin and biological spores such as anthrax.”
Check out this LLNL video that provides a glimpse into the material’s development.
Credit: Lawrence Livermore National Laboratory; YouTube
The research, published in Advanced Materials, is “Carbon nanotubes: Ultrabreathable and protective membranes with sub-5 nm carbon nanotube pores” (DOI: 10.1002/adma.201670197).