While warfare has changed dramatically over the centuries and more specifically over just the past half century or so, the uniforms supplied to those involved in the fighting have changed perhaps even more dramatically. At the U.S. Army Natick Soldier Research, Development and Engineering Center (NSRDEC), all of the services’ uniform design efforts are researched and developed for the Army, Navy, Marine Corps and Coast Guard. The Air Force is shifting its operation there shortly as well.
NSRDEC has some very specialized and unique facilities to test evaluate textiles using the very latest science and technology including a thermal test facility, a climatic chamber, shade evaluation and also a footwear performance lab. It even has a Design, Pattern and Prototype Team. Some of the team started out at Natick designing while others have experience in the clothing industry itself, working in everything from fashion design, children’s clothing and dressmaking to active wear and footwear.
Heide Schreuder-Gibson, Ph.D., is on the Materials Research Team at NSRDEC where she focuses on new materials to place on fabrics. Although she is not a textile scientist, she conceives ways to work new chemical treatments into fibers, develops fabric possibilities to pursue and works with the prototype team on garment design.
“Here at Natick, it’s really nice to have all those teams interacting because sometimes the fabrics I want to use might require a different kind of design than we used in the past,” explains Schreuder-Gibson. “One feature we’re trying to improve upon is the liquid repellency of the fabrics so that toxic chemicals, water, oils and fuels could just roll right off the uniform without soaking in. We do have liquid repellents now; we’re just trying to make them more powerful so we get really true, good roll-off of all kinds of liquids.”
Another thing that they’re working on is responsive materials that would include pores that can close and open on command. It would provide comfort and breathability in an unthreatened state but would offer protection in a defensive state.
If Schreuder-Gibson’s team develops a super shedding fabric using a chemical treatment, they would want to work with their fashion and garment designers to try to exploit that super shedding feature by tweaking the design of the garment, according to Schreuder-Gibson. The current uniforms have flaps, pockets, reinforcing seams and features that might hold up a drop and keep it from shedding well.
“I could talk to the designers about new concepts, hiding pockets underneath flaps that are designed to let the drops just roll right off. Collars, cuffs and all the normal things you wouldn’t think twice about, well if I came up with a super shedding fabric, I might think twice about some of those features and work with them to exploit that feature of the fabric,” says Schreuder-Gibson. “This is big, growing area and a lot of universities and companies are getting more and more involved in this whole idea of specialized fabrics to protect the wearer. If I come up with a really cool textile, I don’t want it to be defeated by using old-fashioned garment design. Maybe we can exploit our features by working closely with the garment design. We are now facing the prospect of being able to scale up and manufacture using what’s been developed in the lab.”
Less than a decade ago, Schreuder-Gibson reports it was still very much industry basics being considered, and the Natick teams were just demonstrating the possibilities in the chem lab. But now they are at the place where they’ve selected the innovations that are most promising and are starting to consider how they will scale up to full production as well as how garment design can further increase performance. While one team is considering the concerns of scaling, another teams can already be mocking up prototypes and testing performance.
Schreuder-Gibson works closely with her husband, Phil Gibson, at Natick. Gibson is an engineer, and Schreuder-Gibson is a chemist. She works on the physical fabric treatments, and he tests, among other things, the “transport measurement,” or breathability and wicking qualities of the fabrics.
“Much of my work is involved with protecting the soldier and providing as much comfort as possible with those fabrics; that’s a balancing act,” says Schreuder-Gibson. “I’m able to – because of his research – make very small amounts of materials, films or fabrics that I would like to put in the clothing system and rapidly test them to see if they are going to have good comfort measures. Phil invented a miniaturized way of doing that testing.”
What she is most excited about is some work she did with her husband a few years ago on electro spinning, making nano-fibers with a very specialized process. For many years it was just an academic pursuit. The couple was aware of its use by some companies to make high-performance filters. But the question was whether that would ever be practical for garments or clothing.
“We’re excited about the fact that, just in the past year, this new material has made its way into manufacturing and sports textiles. This is really the first introduction of new nano-fibers or ultrafine microfibers into protective clothing systems. We’ll be able to spin these fibers and make them stretchy, which Polartec NeoShell has actually done and they are selling this fabric for the sports market. They are durable and the stretchiness gives us more design choices than we used to have,” she says.
Schreuder-Gibson continues, “Such new fabrics give us more surface area, better filtration capabilities and more clothing design options so that we can start looking at conformal clothing, stretch clothing that still offers a high degree of protection. This is the tip of the iceberg in producing new nano-fiber fabrics that are going give us some new capability. Up until now it was a niche area with the greatest application in filtration and biomedical high-end kind of materials. But it’s starting to look like it will be practical in the future to think about making garments and clothing out of material like this.”
Annette LaFleur, team leader for the NSRDEC Design, Pattern and Prototype Team, works on what she calls the design details, most importantly designing clothing with features that enhance the user’s ability to perform his mission, maintain a good quality of life and still be provided with protection as well as survivability.
“One of the challenges is to keep costs low when designing to requirements provided from the field, keeping in mind every bell and whistle adds cost to an item,” explains LaFleur. “The fewer cut parts [pattern pieces] and fewer complex design features that add only the ‘cool’ factor and not add to the practicality, the better. It is very true that designing an aesthetic protective garment or item is key, but it’s challenging with cost factors. What good is an item that a soldier doesn’t want to wear?”
LaFleur admits it is also challenging to design highly protective items, such as armor, while considering weight and bulk factors, especially if there are material limitations. With that said, her team’s focus is on the fit and ease of use to make the best item possible. Technology advances in pattern software, materials and manufacturing methods make room for better designs overall.
“But requirements for highly protective gear and clothing provide military clothing designers the challenge of not overburdening the soldier by carrying or wearing too much to hinder their performance,” LaFleur says. “Over recent years, the operating environments and threats dictate the need for ballistic and flame protection as well.”
Interestingly during wartimes, civilian fashion designers take features from military items and implement them into their lines. This is akin to increases in Humvee sales during the Iraq war. Fashion sales tend to mimic the environment of the world.
“In past war times, we saw military trends on the runway – combat boots, trench coats, epaulets, broaches, colonial-like jackets, belted blouses, etc.,” says LaFleur. “I see it like people are thinking of our soldiers as role models and want to dress like those who are brave and stand for our country’s freedoms. It is neat that our soldiers influence fashion, if you think about it. It is rewarding to design clothing for the ‘ultimate athlete’ every day. Our soldiers deserve all the credit in the world. If we can somehow design items to make their jobs a little bit easier or so that wearing protection is less noticeable, then at the end of the day it is all worth it.”
Cornell University Research
Some of what the NSRDEC is trying to accomplish relates to the work of Dr. Kay Obendorf at Cornell University. Research is ongoing in the effort to develop fabric surfaces that repel both water and oil, according to Obendorf. “They’re using new chemical treatments on the surfaces or manufactured roughness on the surface to get both super hydrophilic and super oliophilic surfaces. That is going to repel the liquid chemical toxins and also liquid-borne biological toxins. The concept of developing such fabric was more of an idea than an accomplishment.”
Obendorf continues, saying, “They’re looking at these metal organic frameworks, or ‘MOFs,’ in which you can design a cavity. This has been done for fuel cells so that it will have this cavity that’s designed to absorb the chemical toxin. We’d also like it to be self-decontaminating so that anything that gets through or is a threat is changed to something less toxic.”
Work continues in the search for materials that will bring down the chemical toxin levels. Researchers are also looking at materials that will kill or inhibit biological toxins as well as for self-decontaminating materials using a whole array of anti-microbial and anti-fungal materials.
But in the area of chemical detoxification, metal oxides or polyoxamethylates may be used. These will actually break down the chemical toxin into less toxic materials. Some of these metal oxides are also antimicrobial, so the wearer gets some self-decontamination of both.
“My own research is about the self-decontaminating because one of the things I find intriguing is that we can use these things in other than military purposes. For example it is now possible to make self-cleaning textiles. These finishes can be put on regular textiles which will deal with volatile organics and clean your air as you are using them for normal textiles,” she says.
Obendorf likes the potential for some non-military applications. She’s also interested in all kinds of environmentally-responsible material.
One of her graduate students is developing a micro-porous structure where the pore size is responsive to moisture. Others at Cornell are also working on chemical and biological sensors; they want to create materials that can sense the threat and give a signal that the soldier is under duress. Sensors are a big area of research, according to Obendorf.
“It is exciting to molecularly engineer these MOFs to meet various end-use purposes – whether fuel cells, filtration or protective clothing for military or occupational purposes. Metal organic frameworks are metal atoms with organic linkers which make a cage that will absorb other compounds,” Obendorf explains.
From 2006 to 2012, some of these concepts have gone from being in the research stages to being used in various filtration and other situations including fuel cells. “There is often an easy crossover of the application of these materials in regular textiles for filtration,” adds Obendorf. “These can be described as passive materials with an active function. The fabric on your chair or the carpet is doing something beyond just being the chair covering and floor covering. It is actually being used to improve air quality; they can eliminate microorganisms, kill bedbugs or whatever it is you want to do. The reactive textiles that are going into the military have these other domestic uses which can be beneficial and give us better public health.”
Oklahoma State University Research
Huantian Cao’s research, when he collaborated with researchers at Oklahoma State University, centered mainly on the comfort issues related to all sorts of protective clothing. “There is always a need to find a great balance between sufficient protection and appropriate comfort. Military uniforms, especially the body armors, are quite heavy and cause a lot of the issues with comfort. Our work on a liquid cooling vest in Oklahoma was involved with firefighters and the hazmat workers. The needs are similar, but the technology we developed was not directly able to be used by the military.”
One issue is that the firefighters often carry heavy things like air bottles and equipment, and their time is quite restricted. Typically a firefighter must leave a building after 40 minutes – much shorter than the time the typical military soldier is engaged in battle. But the needs of military personnel are very much the same; they must carry heavy equipment in addition to the body armor which is already very heavy and hot. Increasing the comfort and providing better cooling are top priorities for the military personnel as well as for those individuals in such activities as firefighting. The difference is military personnel are often in their uniforms for eight hours a day, so it might not be reasonable to have the same uniforms.
“It is important to have the body perspiration easily evaporate so the person doesn’t feel they are in an unbearable type of heat; that’s one thing we were working on,” explains Cao. “The group led by Dr. Donna Branson at Oklahoma State University also worked on the QuadGard armor, a patented body armor system. The U.S. Navy and Army provided the funding directly for the uniform. The goal was to provide limb, arm and leg protection for the soldiers in Iraq and Afghanistan. The protection provided by traditional body armor – a bulletproof vest and helmet – significantly reduced the death rate of the soldiers; however, the arms, legs and limbs were not protected by the vest worn.”
Roadside bombs and IEDs cause suffering for lots of soldiers. Branson and her team developed something lightweight but still able to provide protection from roadside bomb threats.
UC Davis Research
Professor Gang Y. Sun of the University of California-Davis had been working with nano-fibers and nano-fiber members, which are extremely light and thin. They also have ultra-porous structures as well as chemical and biological function additives. These are made into liners for uniforms, designed to replace the current heavier materials of the uniforms. The main purpose is to provide function and to be much lighter in weight.
The charcoal or carbon particles coat the surface of the fibers and absorb any chemical agent that is present. It’s heavier in a chemical-biological uniform, according to Sun. “If we can make the nano-fibers lighter and thinner, it will be a big improvement. This is the research we have been doing the past several years; we’ve derived a system of membranes. Our work has shown it is possible not only to improve the functionality and practicality of fabrics, but we’ve developed several processes that can mass produce nano-fibers as well as the membranes. The processes can be very easily industrialized in large-scale production.”
Many challenges come with this work. Sun describes the goal of creating the ideal material with the ideal function; there is always room for improvement. With that comes the work to create the best comfort, absorption of moisture vapor and mobility possible. “Perfection of the fabric is always a challenge,” adds Sun. “In addition to developing new technology and having a new patent, we are also working to have more environmentally-friendly anti-microbial techniques including having UV light as an activating source.”
Sun’s research dovetails with the needs of clothing for workers in the agricultural industry. In California there have been a number of deaths each year as farm workers cope with temperatures that can soar to as high as 114 degrees in the summer. Recently the worst year in California history occurred when six workers died as a result of the heat stroke.
A survey was done of the materials used. Due to the application of pesticides, workers are required to wear long-sleeve shirts. The UC Davis team developed a lighter material to reduce the heat threat, and they are trying to find one more air-friendly so that wind can go through the fabric and reduce the heat.
“Though there is some crossover with research and applications with clothing for farm workers and those in the military, we have to face the fact that farm workers cannot afford nano-fibers,” Sun says. “We worked with denim fabrics to make ones with higher air permeability through thinner fabric and by changing the design with holes punctured in different areas of the cloth so that air can pass through the fabric and onto your skin more easily. It’s quite exhausting wearing long-sleeved shirts, thick pants and large boots out in the 100-plus degree conditions. The challenge comes in both protecting the workers from all the hazards by keeping the body fully covered at the same time you are keeping them as cool as possible.”
Research is done with a human mannequin to measure increased heat loads to reduce the heat threat. “Holes punctured on the clothing in areas where the workers don’t have direct contact with pesticides, such as the legs or the back, can help to allow more air flow at the same time keeping workers protected where they need to be protected,” says Sun. “The chemical and biologically protective clothing and its antimicrobial functions are the things we work hardest on at UC Davis. In addition to those things, we’re working hard to keep comfort in the forefront to make life easier and possibly save lives. We’re hopeful we can at least reduce heat stress for both farm workers and those in stressful areas serving in the military.”
