percolation threshold

in a composite material
https://doi.org/10.1351/goldbook.08848
Minimal volume fraction of functionally active small particles evenly dispersed in a non-active matrix, at which the long-range (infinite) functional connectivity in the system is achieved.
Notes:
  1. A desired transport through the composite material is not possible below the percolation threshold. Percolation threshold is about \(\pu{0.3}\) to \(\pu{0.35}\) (by volume) for composites with nearly spherical disperse particles while it can be even below \(\pu{0.10}\) for composites with short fibers, depending on the fibers’ aspect ratio (the length to diameter ratio).
  2. Electrically conducting polymer composites composed of carbon black microparticles dispersed in a rubbery matrix are transposed in the electrically conducting state above percolation threshold.
Source:
PAC, 2022, 94, 15. (Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)) on page 40 [Terms] [Paper]