Breathability/Moisture Management

A highly efficient breathable fabric material enables the user to control body temperature and experience physical comfort by controlling heat loss from the system while at the same time removing excessive sweat. The overall effect is to create a more comfortable condition on the skins surface.

One of the first types of fabrics marketed to confer improved insulation was the range of breathable Gore-Tex fabrics. These fabrics are constructed by lamination of a waterproof bi-component membrane to a range of substrates, such as expanded poly-tetrafluoroethylene impregnated with an oleo phobic polymer. The membrane is highly porous, and the width of the pores, around 100 nm, is critical to the effectiveness of the fabric: the fabric can allow perspiration to escape but still confer protection from rain.

Another range of materials providing enhanced insulation includes the Stomatex fabrics. In these fabrics an elevated temperature is maintained to prevent condensation of perspiration. Vapor trapped beneath the fabric is removed by the action of tiny pumps present in the material. Each pump consists essentially of a deformable chamber and an exit pore. During the use of the material, vapor is released from each chamber by virtue of the flexing of the fabric. With higher levels of physical activity on the part of the wearer, the pumping action is correspondingly increased. The performance of the material is thus controlled to match the rate at which the wearer is perspiring.

Micro Thermal Systems of England developed its award-winning technology over five years and in 1999 it received a Department of Trade and Industry Smart prize for the successful commercialization of its innovative technology. Neoprene is an oil/heat-resistant synthetic rubber. Current specifications of Stomatex described as breathable neoprene are made from closed-cell foam neoprene. These fabrics can be applied as laminates or loose linings according to users requirements. The thickness (thermal insulation) of the insulating component varies from two millimeters (mm) to six mm, with the most frequently used being between two and five mm.

In dry condition, the thousands of tiny chambers and pores formed in the body of the Stomatex garment efficiently evacuate sweat as it evaporates from the skins surface. Used in wet conditions in thermal vests, shorts, under dry suits and wet suits, Stomatex traps air in the chambers, which, acting as an excellent insulator, makes the garment warmer than a similar garment made from ordinary neoprene, which does not allow sweat to evaporate. Because Stomatex material has the ability to remove excess heat and sweat, the suit does not allow the inside temperature to rise in or out of the water. The cast of 'Harry Potter and the Philosopher's Stone' was grateful for the warmth provided on the set by tailor-made Stomatex thermal undergarments. Stomatex is on permanent exhibition at the British Science Museum as an example of an advanced biomimetic material.