General silica gel is a good electrical insulator, the conductive mechanism of composite conductive silica gel has two theories, namely, chain conductive path and tunnel effect.

Chain type conductive path:

The mechanism of the chain conductive pathway is that the packed particles must be close to each other within a few tenths of a nanometer, so that the pressure difference can be generated, and the π electrons of the packed particles can move by the chain transfer to achieve the current passing through. The dispersal state of filler particles in rubber to form a chain lock must have a certain amount of filler, in order to appear a strong electrical conductivity phenomenon, so the most important factor governing the electrical conductivity of rubber is the amount of filler, which is the most classical explanation.

Tunnel effect:

The chain type conductive path is established on the premise that the filler must form a chain lock. However, when rubber is stretched under an electron microscope, there is no carbon black chain, but it still conducts electricity, which is the tunneling effect. When conductive particles do not contact each other, there is a polymer isolation layer between the particles, which hinders the directional movement of free electrons in conductive particles. This barrier can be regarded as a barrier with a certain potential energy. For a microscopic particle, if its energy is less than the energy of the barrier, it has the possibility of being bounced off, and it has the possibility of going through the barrier. The phenomenon of microscopic particles passing through the barrier is called penetration effect, also known as tunnel effect.