A Study of the Effect of Perspiration, Laundering, and Abrasion on Polyester Performance Fabric
By Tony Kedzierski
The purpose of this project was to determine if abrasion, perspiration, and laundering had an effect on the wicking ability of performance fabric. Wicking is the ability of fabric to move sweat away from the skin. It keeps athletes cool and dry during competition, helping them regulate their body temperature. Wicking depends on a fabric’s capillary action. Capillary tubes are areas found within the weave of material. Larger tubes will wick faster; narrow tubes will wick slowly. Longer tubes will wick farther; shorter tubes will wick a shorter distance.
A Vertical Wicking Apparatus was used to test these variables. The distance distilled water traveled up each sample was measured. Averages were compared to results of testing on untreated control samples. All three variables wicked farther than control samples. Viewed under a microscope, abraded fabric showed capillary tubes had gotten wider and narrower. Fibers had been broken, blocking tubes and making flow uneven or impossible. Dried perspiration left mineral build-up that slowed capillary flow. Surfactants in the laundry detergent reduced surface tension of the water, allowing it to spread further. Perhaps a finish had been applied to control samples, causing them to wick less than treated samples.
Knowing what variables affect the wicking ability of athletic wear can help athletes better prepare for competition. Abrasion will cause performance fabric to behave differently each time it is worn as weave and capillary tubes change. Proper washing to remove sweat is equally important. Understanding wicking properties of performance fabric gives athletes an edge.
The original hypothesis stated that, over time, exposure to abrasion would negatively affect polyester performance fabric’s ability to wick. The hypothesis was based on the understanding and importance of capillary flow in a fabric’s ability to move liquid along its surface. Because capillary flow must happen in capillary tubes that provide a continuous and uninterrupted flow of liquid, any break in the flow, such as those caused by abrasion of the fabric, might slow or halt the flow. It was also assumed that as the fabric was abraded, the weave of the fabric would stretch and loosen, creating larger capillary tubes that would wick moisture quickly but at a shorter distance. The data collected, however, did not support the hypothesis. In fact, the opposite occurred.
After 30 minutes, the control samples wicked the water an average of 8.1 centimeters. The abraded samples wicked an average of 10.2 centimeters after 30 minutes. This is a difference of 2.1 centimeters. While polyester is made to be highly resistant to abrasion, it is not completely resistant to wear that might come from normal use, such as laundering and wearing while playing sports. There was visible evidence of wear on the abraded fabric strips. The edges were frayed and the fabric no longer felt smooth like the other samples tested. Despite the noticeable wear on the tested fabric, wicking was not impacted. In fact, abrasion resulted in a 26% increase in the wicking ability of the samples tested. Because wicking continued to occur between the 10 and 30 minute intervals, perhaps 30 minutes was not a long enough testing time for the fabric to wick to its peak distance and maximize its capillary effect.
Like abrasion, perspiration had a positive effect on the performance fabric’s ability to wick when compared to the control samples. After 30 minutes, the control samples averaged 8.1 centimeters of wicking distance. The perspiration samples wicked, on average, 10.3 centimeters of wicking distance. This is a difference of 2.2 centimeters, or an increase of 27% wicking capability. As the perspiration dried on the fabric strips, the water portion of the perspiration evaporated leaving the mineral solids on the fabric. There was even visible evidence of the build-up of solids on the fabric because there was a dark line at the top of the fabric’s wicking peak. The mineral left on the fabric might have affected the wicking capability by clogging or narrowing the capillary tubes in the fabric.
Like abrasion and perspiration, laundering improved the polyester ‘s ability to wick. The control samples averaged a wicking distance of 8.1 centimeters. The laundering samples averaged a wicking distance of 18.8 centimeters after 30 minutes. This is an improvement of 10.7 centimeters, or 132% increase of wicking capability. Perhaps, surfactants, surface active agents, in the detergent caused the wicking ability to improve. Surfactants reduce surface tension of water and allow it to spread further across material during laundering. These surfactants might have helped the distilled water move further along the surface of the fabric during testing.
After the 15th trial, treated fabric samples were examined under a 130X microscope camera. The pictures of the abraded fabric showed that some of the capillary tubes became narrow while others were larger. This variation in the weave creates inconsistency in the wicking rate across the fabric. In addition, abrasion creates differences in wicking performance each time the fabric is worn, as rubbing will occur with regular wear and laundering. The pictures also showed fraying and breaking of fibers in the abraded fabric. This would also contribute to uneven wicking. The pictures of the samples soaked in perspiration showed a build-up of minerals on the fabric that could clog the capillary tubes, giving the appearance of a dull white crust on the material. The pictures of the laundered samples showed little difference when compared to the control sample.
It is unclear why the untreated control samples wicked less than the samples treated with perspiration, abrasion, and laundering. One possible explanation is that there was a finish applied to the performance fabric before it was shipped out to stores. A finish is something that can be applied to fabric during or after manufacture to enhance the way it feels, looks, or performs. These finishes can create a fabric that more easily releases soil, is waterproof, fire retardant, odor-resistant, and even softer. Because there was no labeling of the test fabric indicating that it was any more than a wicking fabric, was the finish one that was applied so it had a better appearance in retail stores? Did the abrasion rub a finish off that was applied after manufacture? Did the perspiration dilute the finish? Did the laundering wash it off? Finally, had more time been added to the wicking trials in this study, would the results have been different? Would extra time have allowed the untreated control, perspiration, laundering, and abrasion samples to maximize their capillary effect and reach an equal wicking distance?
The above experiment design, text and photos were copied (with permission) verbatim from a report received from Tony. We were so excited that Tony won so many awards with his project, that we just had to share with our readers. Pickering Laboratories supplied only the Aritificial Persipration; Tony is not related to Pickering in any way. In April, 2013, Tony sent us the following letter:
Dear Ms. George,
My name is Tony Kedzierski. Several months ago you very generously sent me two bottles of your artificial perspiration for use in my science fair project, WICKING: Don’t Sweat It: A Study of the Effect of Perspiration, Laundering, and Abrasion on Polyester Performance Fabric. I have completed my project and have attached my results and conclusions for you to look at. Through this project I learned a lot about the effects of everyday wear and use on performance fabric, as well as the importance of capillarity on this fabric’s ability to wick and keep an athlete dry and comfortable.
In our school district’s science fair (Sci://Tech Exposition), I placed 2nd in the 7th grade
chemistry division. At the regional science fair (Science and Engineering Fair of Houston) I placed first in the junior division for 7th and 8th graders. In addition, I received the Naval
Science Award from the Office of Naval Research, the Most Outstanding Exhibit in Materials Science Award from The ASM Materials Education Foundation, and the Award of Excellence from The Krishen Foundation for Arts and Sciences. Last week, I went to San Antonio, Texas for the Exxon Mobil Texas Science and Engineering Fair. There I placed first in the chemistry division and was nominated to participate in the Broadcom MASTERS national science, technology, engineering, and math competition for 6th, 7th, and 8th graders.
While International Science and Engineering Fair rules did not permit me to acknowledge
Pickering Laboratories on my science fair display board, I was able to mention Pickering
Laboratories Artificial Eccrine Sweat in my materials list/research plan and in the protocol
papers submitted prior to each science fair. Without your generous contribution I do not think my project would have been possible, so I thank you so much for supporting me.
We’re so glad we could help! Congratulations, Tony! And Best of Luck for the future!