Why Silk Feels And Performs The Way It Does

Low Friction Against Skin

Silk is made of protein fibres with good biocompatibility with the human body. Combined with a smooth surface, its friction stimulation coefficient against skin is the lowest of all the common fibres, at 7.4 per cent. That number is the reason silk is chosen for pillowcases, bonnets and scrunchies.

Moisture Behaviour

Silk protein fibre is rich in hydrophilic groups such as amine and amino groups, and the fibre is porous, so water molecules diffuse easily. Silk absorbs moisture from the air and releases it again, which helps skin retain moisture at normal temperatures and lets body heat and sweat escape quickly in summer.

Warmth From A Hollow Structure

Silk both dissipates and preserves heat. Each fibre is built from progressively smaller fibres, so apparently solid silk is more than 38 per cent hollow. The air trapped in those spaces slows heat loss, which is what gives silk its warmth for its weight.

Ultraviolet Absorption

The tryptophan and tyrosine in silk protein absorb ultraviolet light, so silk has a natural anti-ultraviolet function. The trade-off is that absorbing ultraviolet changes the protein chemically, which is why silk left in sunlight yellows over time.