Water not required: self-cleaning clothing
Jessica Green
Senior Research Scientist
Advanced Materials Group
Ever wish your laundry would magically clean itself? That dream might become a reality sooner than you think. At Luna we have been developing a self-cleaning technology for textiles over the past several years. Our work began by trying to solve a problem posed by the Army to make a self-cleaning uniform for soldiers. We approached the problem by realizing if a fabric never got dirty then it would not need to be cleaned or laundered. Therefore we developed a coating that resists soiling by water and oil based fluids through the use of low surface energy materials and nanostructured particles resulting in a superhydrophobic and oleophobic fabric. One of the best examples of superhydrophobicity can be found in nature, the lotus leaf, which inspired our technology.
Images from: http://begoniasscarlet.deviantart.com/art/Lotus-Flower-307031271 and http://www.sunipix.com/plants/plants05.htm
The combination of lowering the surface energy, or surface tension, of the fabric while imparting micro- and nano-scale roughness reduces the adhesion forces that can occur between the fabric and a liquid on its surface. Many researchers in both industry and academia have achieved these results through various methods but not all of the methods are feasible on a large scale (e.g. plasma treatment, chemical vapor deposition). The ability to transfer our technology from the lab to not only our soldiers but also the general population was always an important goal.
We displayed our technology in the Air Force Research Laboratory Technology Warrior Demonstration at Ft. Drum, NY in 2011 (TW11). We outfitted 20 soldiers with Army Combat Uniforms (ACU) coated with Luna’s oil and water repellent technology. The soldiers wore these uniforms during a two week long training while performing activities such as gun cleaning, navigating through the woods, hand to hand combat, camping and eating.
At the conclusion of the training the soldiers were asked to fill out surveys about their thoughts on the Luna treated ACUs. We received a lot of valuable information and positive feedback. In particular, 76% of the soldiers said the Luna treated uniform made it easier to perform their mission. Some of the reasons listed were because they didn’t have to wear extra layers (i.e. rain jacket) and they could wear the same uniform for multiple days because it didn’t get dirty. In addition we also received the Outstanding Warfighting Transition Award at TW11. This is the only staff award given and represents technical contributions of the uniform and our ability to organize and execute a sophisticated and successful demonstration.
If you want to see our fabric in action check out the YouTube video below or read more about our technology in the recent article posted on the Army’s website:
http://www.youtube.com/watch?v=oqgVl-w4HNA
http://www.army.mil/article/95276/Self_cleaning_clothing__wear_without_wear/
Luna’s most recent advances provide high performance repellency in the most environmentally responsible way possible. Most current water and oil repellent finishes use C8-based fluorochemicals which are chemical compounds that have 8 carbon atoms and 17 fluorine atoms. C8 chemistries have received a lot of attention recently due to concerns stated by the US Environmental Protection Agency (EPA) on the toxicity of perfluorooctanoic acid (PFOA), a biproduct of C8 production. We have chosen to use an alternative chemistry that is more environmentally acceptable as well as water soluble therefore eliminating the need of organic solvents which also pollute the environment.
We will be presenting our technology at TechConnect World Summit & Innovation Showcase in Washington, DC on May 14th.
http://www.techconnectworld.com/World2013/
Though we have made great progress with our technology, we don’t want to rest on our laurels. Using the feedback from the demonstration we have continued our work and are making our coating multifunctional in order to provide greater protection for the end user. We plan to have another field demonstration in the Fall of 2013, so stay tuned!
