Quantum-tunnelling composite (QTC) is a flexible polymer which contains tiny metal particles. It is normally an insulator but if it is squeezed it becomes a conductor.

‘Quantum tunnelling composites (or QTCs) are composite materials of metals and non-conducting materials, used to produce pressure sensors’

QTC can be used to make membrane switches like those used on mobile phones, pressure sensors and speed controllers.

What is QTC?

1. QTC material is a pressure/force sensing material.
2. Transforms from Insulator to Conductor with Pressure.
3. Can be formed or moulded into virtually any size, thickness or shape.
4. Durable - it has no moving parts to wear out.
5. Mechanically strong.
6. Can be made to withstand extreme temperatures limits.
7. Versatile, both electrically and physically e.g. Its range and sensitivity can be altered
8. Intrinsically safe - the material is a contactless switch, ideal for spark free operation.
9. Can be directly interfaced to standard electronic and electrical devices
10. This flexible polymer exhibits extraordinary electrical resistance change when deformed by squeezing, pulling or twisting.

They utilise quantum tunnelling: without pressure, the conductive elements are too far apart to conduct electricity; when pressure is applied, they move closer and electrons can tunnel through the insulator.

In its normal state it is a perfect insulator, but when compressed it becomes a more or less perfect conductor and able to pass very high currents.