A TRANSISTOR made only of fibre is opening the way to intelligent fabrics 鈥� to make clothes that could monitor the vital signs of athletes or rescue workers, for example, or simply be a fashion statement.
Existing electronic clothing usually consists of switches or lights woven into fabric and controlled by plug-in silicon circuits. Now Olle Ingan盲s and colleagues at Link枚ping University in Sweden have produced fabric in which the fibres themselves act as the components of a transistor.
To make it, Ingan盲s coated fibres in the conductive polymer PEDOT, or poly(3,4-ethylenedioxythiophene). He then took two of the resulting conducting fibres and stuck them together with an electrolyte. Applying a voltage to one fibre causes the electrolyte to react with the polymer coating the second fibre, switching it from a high to a low-conductivity state 鈥� making the fibres and electrolyte act as a simple transistor (Nature Materials, DOI: 10.1038/nmat1884). Using conducting and insulating adhesives, these transistors can be connected to form a variety of circuits.
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The transistor operates on a relatively low voltage of 1.5 volts. Previous efforts to build organic electronics have been modelled on field effect transistors and so require much higher operating voltages. 鈥淚 wouldn鈥檛 like to have 1 kilovolt wired into my clothing,鈥� Ingan盲s says.
In terms of performance, the electronic fibres are not too impressive. In fact, Ingan盲s admits, 鈥渢hey are tremendously slow鈥�. One advantage of using organic materials is that they could be made very cheaply using ink-jet printing.
