Chemical Binding
Chemical binding processes between water molecules and protein structures define the moisture-handling properties of sheep fiber. Wool keratin sorption describes the way water vapor is attracted to the polar groups in the amino acid chains of the keratin protein. These water molecules form strong hydrogen bonds with the fiber at the molecular level, causing the structure to hold more moisture than most other natural materials.
Structural Swelling
Absorption of water into the fiber causes the diameter of the wool to increase as the keratin chains push apart to accommodate the moisture. This physical change is a direct result of wool keratin sorption and accounts for the high flexibility of the fiber when wet. The swelling process is reversible, and the fiber returns to its original dimensions when the water is removed through drying.
Comfort Performance
Heat is released when water molecules bond to the keratin, a phenomenon known as the heat of wetting. This energy release makes wool feel warm to the wearer even when the fabric becomes damp. Wool keratin sorption allows the material to act as a buffer against sudden changes in environmental humidity, protecting the skin from feeling clammy or cold.
Saturation Point
Limits of moisture uptake are reached when all the available binding sites on the protein chains are occupied. At this stage, any additional water exists as liquid on the surface or within the large pores of the fabric. The saturation point for wool keratin sorption is much higher than for synthetic polymers, making wool an ideal choice for high performance outdoor apparel.
