Second Skin for a Lighter Warfighter
Academic, research and industry teams join forces to improve uniform materials.
New fabrics now under development will one day relieve troops from the burden of wearing additional garments to protect from chemical and biological attack. The effort, dubbed Second Skin, is being led by the Defense Threat Reduction Agency’s Chemical and Biological Technologies Department. The goal is to weave a new generation of multifunctional materials that can be manufactured into everyday military uniforms but use molecular-level technologies to protect against such attacks as soon as the wearer enters a contaminated area. The program is budgeted for $30 million over the next five years.
Hooded, heavy and cumbersome suits in hot desert climates worn in anticipation of possible chemical attacks and the accompanying discomfort would become a thing of the past if the Second Skin program is successful, according to Tracee Harris, science and technology manager for Novel Materials, Chemical and Biological (CB) Technologies Department, at the Defense Threat Reduction Agency. “The vision of dynamic multifunctional materials for Second Skin technology is to enable the manufacture of autonomous protective garments—in other words, garments that can respond to a CB threat by optimizing the balance between the CB protection that the garment can offer and thermal comfort for the wearer,” she explains.
Harris cites studies performed by the U.S. Army Research Institute for Environmental Medicine that show a physiological effect that current suits have on soldiers’ abilities to perform their mission. “They’re performing moderate work, marching under those conditions, under high relative humidity, and high temperatures,” she says, adding that in normal use, soldiers usually must rest after wearing the suit for one hour. Generally, suits are issued to troops for use only in situations where they may be marching into a known threat.
The goal of the Second Skin program is to develop a fabric for a uniform that is comfortable one minute, and highly protective the next, without the wearer taking any action. “Is there a way to autonomously switch the suit from a benign, highly breathable state to a protective state ‘on demand’?” she asks.
A fabric that meets what she describes as multifunctional performance objectives is the answer. “In this case, this material is going to be able to do two things: It’s going to be able to react with the chemical agent to decontaminate it, and at the same time, it’s going to be able to close its pores and block the transport of that agent through the material,” Harris explains. Because troops normally operate in environments where they do not know what kind of chemical threat they face until they face it, Harris says Second Skin is being developed to protect against a whole range of different chemical agents. “Certain contaminants are going to be percutaneous hazards. Those are the ones where, if they get on your skin and through your skin, they will cause deleterious effects. We want to be able to protect against a broad range of such hazards,” she explains. As part of the research, the suit material is being developed with this specific capability in mind.
The Second Skin program seeks to tie together numerous lines of research that have already been done into making fabrics resistant to and protective against chemicals and biological agents. Chemical and biological hazards each pose their own unique challenges that the scientific teams hope to overcome in the course of the next five years.
Harris emphasizes that in the chemical area, the primary challenge is keeping a chemical from reaching the skin, as well as decontaminating the chemical from the uniform once it comes into contact with the fabric. Current chemical protection suits that employ the Joint Service Lightweight Integrated Suit Technology often contain a top layer that sheds the liquid chemical agent, she explains. Inner layers of fabric capture or absorb any chemical that penetrates the top layer. In addition, metal salts are usually added to the inner absorptive layers, providing further active decontamination of chemicals.
Current chemical protection suits also provide biological attack protection because they act as a filter to keep out organic materials and ensure that they do not reach the wearer’s body. Harris uses the example of an anthrax spore to explain the challenges biological hazards pose. “Most of the biological agents are inhalation hazards,” she explains, adding that most do their initial damage when they are inhaled through the nose or mouth and into the lungs. “If they are sitting on your suit, the stuff will go flying.” The Second Skin program seeks to create a fabric that can minimize the effect of biological agents that land on the fabric and deactivate threats such as anthrax spores as they lie on the surface.
Another goal of the Second Skin program is to take research into the rapid detection of a chemical or biological threat and integrate that capability into the fabric. “We’re building logic into the material,” she explains, adding, “It’s kind of passive in a way. You’re putting the material that is going to react with the chemical into the fabric.” One of the organizations participating in the Second Skin program, Lawrence Livermore National Laboratory, is developing polymer brush layers composed of carbon nanotubes and embedded with reactive nanoparticles. “When that chemical comes in, it reacts with that nanoparticle, and the byproduct is an acid that is going to cause that polymer brush to detach itself from the layer of fabric that has been built upon with the chemical,” she explains. The brush effectively removes most of the chemical, and then forces any remaining residue to drop off the fabric.
The Second Skin program is slated to run for five years, with teams of research labs, academic researchers and companies involved in the work. The three teams are led by Lawrence Livermore National Lab, the U.S. Army Natick Soldier Center and FLIR Systems Incorporated. During the first 15 months of the program, participating organizations will focus their research on understanding how to develop the mechanism for detecting and protecting against a chemical or biological attack on the wearer. The focus of the second 15 months of the program is on understanding how to drive the amplitude of the response so that it functions the way that they envision the material working, Harris says.
Development of Second Skin will benefit all of the military services, but military organizations with specific expertise in the use of chemical and biological attack suits also are working with and providing guidance for the project. Even though it is leading one of the research teams, the Army Natick Soldier Center also is sharing expertise with the other teams in one area. “[Natick] is where the test and evaluation of the garments occur. They understand all the different fabric technologies that we are currently using, and so each of the teams is working with Natick,” explains Harris.
“Each of the teams has a test-and-evaluation component to it and also has an industry partner that understands garment materials and how this technology can be integrated into that material,” she adds. The project also is looking into the practicality of including other desired capabilities in a fabric that can protect against chemical/biological attack, such as fire resistance and field durability. The teams are also exploring ways to reactivate the protective functions of the fabric if needed once it is laundered.
Harris says that five years from now, at the end of the program, they will have swatches of fabric that will be expected to sense a chemical or biological threat and provide a response to the attack. It is expected that a follow-on program will focus on techniques leading to the manufacture of the military uniforms.