Materials through the ages: Material for swimwear

Materials World magazine
,
5 Jun 2012
man in modern swimming costume

From ultrasonically welded swimsuits to UV-protected spray-on bikinis that help the wearer give up smoking – swimwear design has come a long way since its humble 17th Century beginnings. Maria Felice takes a look at how materials science is making swimmers superhuman.

Only a select few of us will be swimming for gold this summer, but plenty of us will be enjoying a dip in an ocean near or far, or indeed continuing regular indoor swimming. The materials used for swimwear have evolved tremendously over the years, together with the function of swimwear – initially one of modesty and now one of comfort and speed.

Classical times to today

All classical pictures of swimming show nude swimmers. Slightly later than this people wore underwear garments, such as the Japanese fundoshi.

In the UK in the 18th Century it became illegal to swim in baths in the nude, and in the 19th Century this was extended to swimming in the nude even in the countryside. Men reluctantly began swimming dressed in drawers and waistcoats, although women had been wearing swimsuits from as early as the 1670s. Those who could afford it wore an oversized garment made of yellow canvas (yellow to conceal the yellowing effect of the bath water), although the material was better suited to making tents and sails because of its heavy-duty nature. The gap between the garment and the woman’s body filled with water so that it remained away from her body and concealed her shape. Poorer women wore more comfortable linen garments but these clung to their bodies and were, therefore, less modest.

Flannel is a soft fabric made of woven wool or yarn and has been around from as early as the 16th Century. It was used in the 19th Century to keep people warm while sea bathing, which was being strongly promoted for its health benefits. In the early 20th Century swimsuits were typically made of knitted wool, which became very heavy when wet. Silk, which did not have this disadvantage, was an option for those who could afford it and for participants in the 1924 Paris Olympics. Rayon is artificial silk made of regenerated cellulose fibre and, therefore, considered semi-synthetic. It was developed in the 1930s and became an affordable option for swimmers.

To this day it is synthetic materials that are used in swimwear, as they are typically light, comfortable and cheap to produce. In the 1980s, Speedo made its first nylon and elastane swimsuit. Nylon was first produced in 1935 and is a thermoplastic, silky polymer less absorbent than wool or cotton. Nylon fibres are so durable that they are used in critical applications such as seatbelts. Elastane is known for its exceptional elasticity, or what most people would call ‘stretchiness’. Indeed, it is also referred to as spandex – an anagram of ‘expands’ – although in the UK it is commonly referred to by the brand name Lycra. Developed in 1959, it revolutionised many areas of the clothing industry.

A disadvantage of nylon-elastane swimsuits is that they can lose their shape. Polyester swimsuits are a popular choice with those who swim regularly, because they last a very long time. However, they do not dry so quickly and are less flexible, with a more ‘clothes-like’ feel, so are not popular for race swimming. Silver nanoparticles are used nowadays to make swimwear fabrics antibacterial. Bacteria metabolise oxygen using enzymes, and silver kills bacteria by disabling these enzymes. Silver also destroys viruses and fungi in a similar way. Nanoparticles are particularly effective because, due to their tiny size, they have a large surface-area to volume ratio, meaning a small amount of silver can do the job.

Competitive swimwear

‘Was it over the line…?’ Cameras are still not used to aid football officials in making decisions on whether or not a goal was scored – some people like the natural, human way of doing sport. This is not the case in professional swimming, with swimwear developers carrying out intensive research to identify useful technology and apply it to swimwear. For example, teams from Speedo learnt about shark skin from the Natural History Museum and about drag reduction from NASA.

High-technology swimwear differs from conventional swimwear in two main ways – it does not absorb water and it reduces drag through water. The materials used sometimes mimic the skin of marine animals and are therefore examples of biomimicry. High-tech swimwear fabric is often a composite material consisting of nylon and elastane. Panels of polyurethane, which combines the best properties of rubber and plastic, are sometimes included in swimsuits in areas where drag is greatest. It holds in the muscle or fat in this area, making swimmers more streamlined, as well as trapping air and increasing buoyancy.

The controversial Speedo LZR Racer (pronounced ‘laser’) used during the 2008 Beijing Olympics was made of woven elastane-nylon and polyurethane. High-tech manufacturing techniques were used as well as advanced materials. For example, the seams of the suit were ultrasonically welded to reduce drag. All this was not in vain – 94% of all swimming races in Beijing were won in the suit. However, some people claimed that this was an example of ‘technical doping’. As of January 2010, two FINA (International Swimming Federation) regulations took effect. First, the fabric used for swimwear must be a textile or woven material. Second, swimsuits of both genders must not go further than the knee and not cover the arms. Swimsuits covering large areas of the body had become popular because the advanced materials produce less drag than human skin.

The Speedo Fastskin3, which will be used during this year’s Olympics in London, consists of a knee-length suit, a cap and goggles. Let’s see what this racing system will do...

Fashion and technical swimwear

High-tech materials have not only captured the imaginations of racing swimwear designers, but also of fashion designers working on innovative fashion-meetstechnology creations.

Spanish designer Manel Torres, together with scientists from Imperial College, London, developed spray-on fabric consisting of wool, linen or acrylic fibres suspended in a solvent and stored in a high-pressure can. It dries instantly on touching the skin and, unlike body paint, can be washed and worn again. The spray-on bikini was designed in 2007 as an instant bikini-top – perhaps suitable for unusually sunny days when you fancy a dip but do not have your swimsuit in the car. As well as fibres, the suspension also includes UV-protection particles and nicotine, helping the wearer give up smoking while sunbathing safely. A simpler bikini, the ‘malignant mole bikini’ was designed by Fiona Carswell. The bikini appears normal, but when exposed to direct sunlight dark moles appear on it, reminding the wearer of the harms of sunbathing.

The PhotoPhore swimsuit lights up when in contact with water and is designed by CuteCircuit, the team behind the award-winning Hug Shirt. Their swimsuit is inspired by the photophore, a light-emitting organ that appears as luminous spots on various marine organisms. It seems that when material science meets swimwear design, there really are no limits.