A good sweater’s coziness can be attributed to the friction between adjacent loops of fiber in knit fabrics, allowing them to take on various shapes and conform to body contours.
Fiber Friction: The Key to Cozy Knits
A good sweater is like a cozy hug made out of yarn. For that, you can thank friction.
Friction between the adjacent loops of fiber in knit fabrics gives them the ability to take on various shapes and conform to the contours of a head or body. This phenomenon is known as “metastable states,” where a fabric can form multiple possible shapes depending on how it’s stretched and released.
The Science Behind Cozy Knits
When a knit fabric is stretched and released, it springs back. However, unlike a rubber band that always returns to its original shape, a knit fabric can take on many different forms due to the friction between its loops of fiber. This property helps explain why knitters often go through a process called “blocking,” which involves wetting the fabric, shaping it, and laying it out to dry. Blocking locks the fabric into just the right configuration to provide warmth.
The Role of Friction
Researchers at the University of Rennes in France conducted experiments on knit fabrics created with a basic stitch known as stockinette. They stretched a square of fabric on a rectangular frame, released the force, and measured the ratio of the fabric’s length to its width. The results showed that the ratio varied depending on how much the fabric was stretched and in which direction, indicating that it could take on various metastable states.
Computer simulations also demonstrated this effect, showing that when friction between the loops of fiber is decreased or removed, the multitude of metastable states disappears. Without friction, the fabric would always spring back to its original shape.
The Importance of Friction
Friction plays a crucial role in giving knit fabrics their versatility and ability to conform to different shapes. This phenomenon not only helps explain why blocking is an essential step in knitting but also highlights the importance of understanding the properties of materials at the molecular level. By studying the behavior of fibers and their interactions, researchers can develop new materials with unique properties that can be applied in various fields, from textiles to engineering.
- sciencenews.org | Fiber friction is the key to cozy knits
