Understanding Why Your Cotton Fabric Shirt Shrinks Can Help You Avoid Ruining a New Shirt.
“Accidents” have happened to many people who toss a new cotton shirt into the dryer without a second thought, only to find it has shrunk to fit a three-year-old.
Cotton fabric is very prone to shrinking; the reason lies in the fibers that make up the fabric of that shirt.
The reason your favorite shirt is damaged may be more complex than you think. (Photo: susandaniels/Getty Images).
Jillian Goldfarb, an associate professor of chemical engineering and molecular biology at Cornell University in the United States, explains that cotton fabric is made from fibers derived from the cotton plant. These fibers are primarily composed of cellulose, a type of natural biopolymer. Cotton fibers are prone to shrinking due to their characteristic of swelling when wet and contracting when dry.
If you’ve ever sweated while wearing different types of fabrics, you may notice a difference. Cotton fabric absorbs moisture very well, whereas synthetic fabrics like polyester, nylon, and spandex absorb less sweat and swell less because their tightly woven fibers do not expand when wet.
Chemically, cotton fibers are twisted together to create fabric, generating tension in the fibers and forming a network of hydrogen bonds. When variables such as temperature and water come into play, this hydrogen bond network can change, causing the fabric to stretch or shrink. This is also why wrinkles form on clothing.
Even though they are all made from cotton fibers, differing weaving methods result in some cotton fabrics being more prone to shrinking than others. For instance, woven fabrics will shrink but less than knit fabrics. When the fibers swell due to moisture, they push the horizontal threads closer together and shrink in one direction. When the moisture evaporates, the fibers contract. This means that the shrinking of the clothing actually begins before they are placed in the dryer.
The inability of clothing to fit as it initially did is a dual consequence of the fibers holding moisture and then drying, combined with the high temperatures in the dryer.
The extent of shrinkage depends on several factors, such as whether you wash them in cold water or add detergent, as detergents can further break down the hydrogen bonds, and how you dry the clothes—whether at high temperatures or air-drying. When air-drying, the temperature is much lower, thus the evaporation process is much slower, and the fibers do not experience “stress” from heat during the shrinking process.
How to Prevent Your Clothes from Shrinking?
First, you should choose clothing made from fabrics that are less prone to shrinking, meaning cotton fabric blended with synthetic fibers or cotton fabric that has been treated to be shrink-resistant.
If your clothing does shrink during use, depending on the quality and weave of the fabric, you can wet the clothing again and stretch them while air-drying to bring them closer to their original size.
Another remedy is to use a steam iron. When ironing, the moisture is reabsorbed into the clothing, which stretches the fibers while applying mechanical force to pull them back. However, you should be careful to apply this method slowly, as overheating can have the opposite effect.
