The formation of conductive silicone internal conductive pathways is the result of the synergistic effect of conductive fillers and silicone matrix. As an insulating elastic carrier, the silicone matrix provides space for the conductive fillers to be evenly dispersed, while the conductive fillers (such as carbon particles, metal powders, etc.) assume the core function of current transmission. When the fillers are dispersed in silicone, they are initially isolated and have large distances between each other, and cannot form an effective current path; as the amount of fillers added gradually increases, the distance between particles continues to shrink. When a certain critical value is reached, some particles begin to contact each other, forming conductive nodes in the physical sense, while the other part of the particles that are very close to each other, although not in direct contact, can achieve charge transfer through the electron tunneling effect - these two methods together constitute a conductive network throughout the material, making the originally insulating silicone conductive.
The formation of this path is not static, but depends on the distribution state of the conductive fillers in the silicone matrix. When the fillers are evenly dispersed, the particles form an interconnected mesh structure in three-dimensional space, each conductive node is connected to multiple adjacent particles, and the current can be transmitted through multiple parallel paths. This multi-path characteristic gives the conductive path a natural "fault tolerance": even if a few local particles are out of contact due to external force or aging, other paths can still maintain current conduction and avoid drastic fluctuations in overall conductive performance. Evenly distributed fillers can also make the current density more balanced inside the material, reducing the energy loss caused by local current concentration, which is an important guarantee for the stability of the path.
If the conductive filler is unevenly distributed and local aggregation occurs, it will have a significant negative impact on the stability of the path. Aggregated fillers will form dense conductive agglomerates. The current inside these agglomerates is highly concentrated, which is easy to cause local temperature rise due to Joule heat accumulation, accelerate the aging of the silicone matrix, and even reduce the bonding force between the surrounding fillers and the matrix, causing the agglomerates to loosen. In the blank areas between the aggregation areas, due to the scarcity of fillers and sparse conductive nodes, the current needs to cross a longer distance to conduct, which not only increases the overall resistance, but also may cause local conduction interruption due to the breakage of a key path. This contradiction of "overheating in dense areas + high resistance in blank areas" will cause irregular fluctuations in conductive performance over time, and even completely lose the ability to conduct in severe cases.
The directional arrangement of conductive fillers will give the path special stability characteristics. Under the action of specific processes (such as magnetic field induction, mechanical stretching), the filler particles will be arranged in an orderly manner along a certain direction to form a directional path similar to a "wire bundle". This structure significantly improves the conductivity efficiency along the arrangement direction, because the current can be transmitted through a smoother linear path, reducing the contact resistance between particles; in the vertical direction, due to fewer particle connections, the conductivity is weaker. Directed distribution paths are more stable in scenarios where unidirectional conductivity is required. For example, in the bending part of flexible electronic devices, fillers arranged along the force direction can better resist the displacement caused by deformation and maintain conductive continuity.
The flexibility of the silicone matrix is also crucial to maintaining the stability of the path. Silicone itself has good elasticity and resilience. When conductive silicone is subjected to external forces such as extrusion and bending, the deformation of the matrix will drive the internal filler particles to move slightly, but will not easily destroy the contact or close distance between particles. This "flexible buffering" effect allows the conductive path to adjust adaptively as the material morphology changes, avoiding rigid fractures. Compared with the conductive path in the rigid matrix, the path in the silicone matrix can still maintain structural integrity after repeated deformation. This is also the key reason why conductive silicone is more stable than other conductive materials in dynamic working conditions.
In long-term use, the distribution state of the conductive filler will also affect the anti-aging ability of the path. Evenly distributed fillers can make the aging process more uniform: aging factors such as oxidation and wear have similar effects on each conductive node, and there will be no local rapid failure; while the aggregated filler clumps are more likely to have particles fall off or poor contact during the aging process due to local stress concentration, causing the path to gradually disintegrate. Therefore, maintaining long-term uniform distribution of fillers is the core prerequisite for extending the service life of conductive silicone and maintaining the stability of the path.
The formation of conductive silicone's conductive pathway is the result of the combined effect of filler concentration and dispersion state, while the filler's distribution uniformity, arrangement and the flexibility of the matrix determine the stability of the pathway from different dimensions - uniform distribution ensures multi-path fault tolerance, directional arrangement enhances stability in a specific direction, and the flexible matrix buffers external forces. These factors together give conductive silicone reliable conductive properties under complex working conditions.
