In addition to its chemical complexity, wool also has a complex physical structure. The surface is made up of overlapping cuticles. Place it under a microscope and you see a scaly surface, which is very different from the smooth surface of synthetic fibres. These scales protect from dirt and are what enable felting to occur.
Lanolin is the waxy coat produced by glands surrounding the cuticle. It protects sheep from the elements and repels water while allowing water vapour absorption. When wool is processed, lanolin is removed. It’s then sold as a wool by-product.
Wool’s interior is intricate being made up of membrane, cortex, cortical cell, microfibril, matrix, microfibril, and the twisted molecular chain and helical coil.