Textile scientists offer fresh insights into why some clothes smell

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

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

Key findings from a study published in Textile Research Journalexplains why some commonly worn fibers are smellier than others when people sweat, says Rachel McQueen, a clothing and textiles scientist in the Faculty of Agriculture, Environment and the Environment, who conducted the research with colleagues at the University of Otago in New Zealand .

“Although we know polyester is smellier when worn next to sweaty armpits compared to cotton T-shirts, we didn’t really know why. We now have a better understanding of how odors are transmitted and selectively absorbed by different fiber types in sweat.” .”

The study’s method, which uses simulated liquid sweat, also offers an important new approach to investigating the problem, he notes.

“Body odors are commonly transferred to clothing through liquid sweat, but research on odor retention in textiles often neglects this route of exposure in testing procedures,” McQueen says, noting that standard scientific methods only involve examining how odor travels through the air into the textile. . “If you had sweaty armpits that never actually touched the shirt you’re wearing, then the fabric wouldn’t smell much.

“By studying the transfer of odorants to fabrics using a liquid sweat solution, we were able to provide a more realistic view of how these smelly compounds actually get into our clothes.”

In the study, the researchers soaked the fibers in a sweat solution for different periods of time and then examined the release of various odor-causing compounds from the fibers using an analytical device that can detect odors in the air in real time – similar to humans. nose yes

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

Sweat, which is mostly made up of water, also has oily compounds that bacteria transform to create odor, McQueen explains. “These oil compounds and fragrances in watery sweat can interact with textiles differently, depending on the fiber chemistry.

“While water-loving cellulosic fibers like cotton and viscose absorb more water from sweat than polyester, polyester doesn’t want to absorb water,” notes McQueen. “It’s more oil-loving and absorbs more fragrances that don’t dissolve in water and more oily compounds that could also break down and smell later.”

The results of the study help explain why clothes made from cellulose fibers tend to be less smelly after being worn than synthetic clothes.

The research also showed that although nylon and wool initially absorbed many odors from sweat, they dissipated them more quickly than polyester. After 24 hours, wool and nylon had much lower odor intensity and were more similar to cellulose fibers.

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

Knowing more about why sweat makes certain fibers smelly can help consumers make more informed decisions when buying clothes, he says.

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

“Basically, if you’re worried about smelly clothes, stay away from polyester. Even with some anti-odor claims on some clothing labels, you should be careful. If the anti-odor property is due to an antimicrobial, it may not be as effective as you think. because there’s another mechanism at play that’s all about fiber chemistry and interaction with odorants.”

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