Quantum Tunnelling Composite Pad

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Quantum Tunnelling Composite Pad
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This small thin, rectangular rubber pad is designed to switch from an electrical insulator to a conductor when compressed. In other words, it’s a pressure sensor. 

The composite is made from a rubbery matrix which contains small particles of metal, usually nickel. The rubber matrix is an electrical insulator and in the inactive state, the conductive metal particles are too far apart for the composite to conduct electricity. When it is activated by being compressed, the metal particles are moved closer together, and electrons “tunnel” through the insulator such that the overall material becomes electrically conductive. 

A material is said to conduct electricity if charge-carrying particles like electrons can flow through it. In quantum mechanics, the location of an electron is described in terms of the probability of it being in a particular place, rather than its exact coordinates. When an electron in a metal particle in the composite approaches the barrier of the insulator, there is a very tiny but not completely zero probability that instead of being stopped in its tracks, it will get through to the other side. Quantum mechanics says that with a large enough number of electrons trying to pass through and a non-zero probability of them doing so, some will get lucky and end up on the other side. The result? The material conducts electricity when compressed. Upon release, the metal particles become too far apart for the electrons to tunnel through.

Quantum tunnelling composites like this have already been used by NASA robots to sense how tightly they are gripping an object, and could also see use as novel touch screens and feeling prosthetic limbs for amputees.

Sample ID: 249

Particularities

State
Solid
Compound
Maker
SEP

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