Textile scientists offer new insights into why some clothes smell better

Have you ever noticed that a polyester t-shirt smells worse than a cotton one after you work out? New research from the University of Alberta now shows why.

Analysis of various fibers soaked in a simulated sweat solution showed that cotton and viscose, which are cellulosic or plant-derived fibers, absorb – and therefore release – smaller amounts of odor-causing compounds than polyester, nylon and wool.

The main finding from the study, published in Journal of Textile Researchexplains why some worn fibers tend to smell better than others when people sweat, says Rachel McQueen, a clothing and textile scientist in the Faculty of Agricultural, Life and Environmental Sciences, who conducted the study with colleagues at the University of Otago in New Zealand. New.

“Although we know that polyester is smellier when worn near sweaty armpits compared to cotton T-shirts, we haven’t really known why. We now have a better understanding of how odorants are selectively transferred and absorbed by different types fibers in sweat.”

The study’s method of using simulated liquid sweat also provides an important new approach to exploring the issue, she notes.

“Body odors are typically transferred to clothing through liquid sweat, but the investigation of odor retention in textiles often neglects this route of exposure in testing procedures,” says McQueen, noting that standard scientific methods include examining only how the wind passes through the air into the textiles. . “If you had a sweaty armpit that never touched the shirt you’re wearing, then the fabric wouldn’t smell too bad.

“By studying the transfer of odors to fabrics using a liquid solution of sweat, we were able to provide a more realistic picture of how these odorous compounds enter our clothes.”

In the study, the researchers soaked the fibers in the sweat solution for various periods of time, then examined the release of various odor-causing compounds from those fibers using analytical equipment that can detect odorants in the air in real time—more like a human. the nose does.

Overall, the study showed that cellulosic fibers took up lower amounts of the compounds when transferred through the sweat solution than textiles made from wool, nylon and polyester fibers, which, conversely, initially released higher amounts of odorous compounds. .

Sweat, which is mostly water, also has oily compounds that bacteria transform to form odors, McQueen explains. “These oily and aromatic compounds in water-diluted sweat can interact differently with textiles, depending on the chemical composition of the fibers.

“While water-loving cellulosic fibers like cotton and silk absorb more water from sweat than polyester, polyester doesn’t want to absorb water,” notes McQueen. “It’s more oil-loving and absorbs more flavorings, which don’t dissolve in water, and more of the oily ingredients, which can also later break down and smell.”

The results of the study help explain why clothing made from cellulose fibers tends to smell less than synthetic clothing after wear.

The research also showed that although nylon and wool initially picked up a lot of odorants from sweat, they dissipated them faster than polyester. After 24 hours, wool and nylon had much lower odor intensity and were more similar to cellulosic fibers.

“This tells us that while polyester still needs to be washed, for nylon and wool clothes, people may be able to refresh them simply by airing them instead of washing them every time.”

Knowing more about why sweat makes certain fibers smellier could help consumers make more informed choices when buying their clothing, she says.

“This is important not only for workout clothes, but also for our everyday wear,” she adds, noting that most of them are fast fashion that contains polyester.

“Basically, if you’re worried about smelly clothes, then stay away from polyester. Even with some of the anti-odor claims on some clothing labels, you might want to be careful. If the anti-odor property is due to an antimicrobial , may not be as effective as you think because there is another mechanism at play, which has to do with fiber chemistry and the interaction with flavorings.”

The study’s findings could potentially also be useful to scientists and textile manufacturers, perhaps in developing polyester to be more water-loving and less attracted to oily compounds, she adds.