Ecological Fabrics
How to power protective clothing in the battlefield has long been an issue. Relying upon a battery pack poses difficulties, especially when the soldiers are sent away from their bases on long missions. According to an assessment made by DARPA ( the United States Defense Advanced Research Projects Agency ) in 2000, a soldier carrying a four-day power supply would have to leave behind 400 rounds of ammunitions and either four days’food rations or a protective mask and first aid kit. In the same year, the US military sponsored scientists at the Army Natick Soldier Center to develop advanced photovoltaic technology (solar cells are used to convert energy from the sun into electricity) for soldiers. Within month they had come up with a new way of making photovoltaic cells (PVCs) from nanoscale particles of titanium dioxide. Whereas existing silicon photovoltaics could only be applied to fragile materials such as glass, Konarka’s photoreactive materials could be printed onto a range of flexible materials ranging from plastics to threads using ink-jet printing techniques developed for newspaper printing. At the moment photovoltaic cloth can only gather 4 percent of the solar energy it receives from the sun, compared to silicon solar cells that can gather 18 percent, however, it can harvest energy effectively from low-light frequencies; the manufacturing process is cheap and opens up the possibility.