Silk: the original liquid crystalline polymer 

The word 'silk' brings to the mind a kaleidoscope of images: silkworm culture in the villages of China, camel trains on the ancient silk road of Asia, the finery of the mediaeval courts, the workshops of Huguenot refugees in Spitalfields and Macclesfield, Victorian velvet and chiffon mills, the parachutes of Spitfire pilots (and the linings of their battledress), QCs' robes, regimental ties, lingerie and expensive cosmetics, crosswires on gunsights, arrestor ropes on aircraft carrier flight decks, GM research labs. Silk, the most ancient textile fibre is paradoxically, the focus of much current research. The production of a substitute for silk has always been one of the goals driving the synthetic polymer industry. In spite of competition from rayon, nylon and teryiene, silk has retained its role as the luxury fabric. Its fibres are strong yet soft; it dyes easily; it does not sag or stretch. It is widely used for sewing and embroidery threads, woven and knotted into fabrics such as satin, chiffon and velvet. The combination of strength, lightness and fineness leads to specialist uses such as parachutes. In the Second World War, RAF Bomber crews had nylon parachutes but spitfire pilots had silk as they could be folded into a more compact bundle to fit into their confined cockpits. Although by far the major use of silk is for textiles, there are one or two other applications. The soft lustre of some expensive cosmetics is due to finely chopped silk and the biocompatibility of silk makes it suitable for sutures and wound dressings [7]. Because of its extreme fineness and strength, spider silk is the traditional material used for cross-wires on optical instruments and there are even a few black-widow spiders kept on the US army payroll to provide cross-wires for gunsights.