Is percolation or percolation threshold phenomenon applicable only in conducting filler-nonconducting polymer matrix system (e.g CNT-Polycabonate) ? or it can also be applicable for conducting filler-conducting polymer matrix (e.g CNT-polyaniline)? Please open the discussion.
Dear Anil, the precolation model has been originally developed for dams and the question was how much cylindrical holes can be drilled into the dam at random directions before it loses its water-tightness. Therefore the problem is quite general: how many elements of definite shape can be placed into a continuum before the maximum length in the forming network becomes infinite (or at least comparable with the sample size). Experimentally this transition can be observed if the properties of the two components (usually the filler in a continuous matrix composite) are orders of magnitude different. This property can be electrical conductivity, heat conductivity, magnetic permeability, diffusion/gas permeation or even mechanical modulus. Experimentally it can be observed easily if the inclusion phase exhibits "higher" property of the listed kind and the matrix lower. If I remember well, it was also used for composites with metal matrix and superconducting dispersed phase.
Exactly, Dr. Banhegyi.connections of fillers with matrix materials is main
Thank you
Anil.
Anil, Gyorgy and all - percolation ptheory for threshold phenomena can only be applied for systems, where the dispersed / distributed phase (particles, holes or else) are statistically randomly distributed (as Gyorgy mentioned about the holes in dams).
As soon as the dispersed phase (particles, holes, droplets) size is less than 1 micrometer in diameter, interfacial interactions are playing the dominant role and it is impossible to statistically randomly distribute the particles - instead, they are forming "dissipative structures" which have very fine complex forms and deliver the connectivity which end up in a threshold, see review or my original publications here:
https://www.researchgate.net/publication/255785634_Metallic_Properties_of_Conductive_Polymers_due_to_Dispersion?ev=prf_high
Chapter Metallic Properties of Conductive Polymers due to Dispersion
All, please also have a look at this Q&A thread:
https://www.researchgate.net/post/Percolation_or_phase_transition_in_conductor_insulator_composites?view=5a152af593553b85e23d06c5
Dear Kumar,
I can give you a simple explanation.
To talk about the percolation threshold, The composite must be contain at less two constituants phases, the electrical properties of these phases must be differents. So in this case, the mesured parameters (conductivity, residtivety, permittivité, ...) of composite versus concentration of one of this constituants should show a sharp changes in behavior at specific concentration. To get this phenomena. The composite must be a mixture of conducting fillers (carbone black, nanotubes, graphite, graphene, ... , also the ionic particules) and insulating matrix ( in general the polymeric material).
Regards
M. El Hasnaoui
Mohamed, it seems you have not read my previous answers. Your "simple" answer is simply wrong, as percolation theory can not be applied for conductive fillers with a particle size of below 1 µm - for the question "why not?" see above and in even more detail my answers to this question:
https://www.researchgate.net/post/Percolation_or_phase_transition_in_conductor_insulator_composites?view=5a152af593553b85e23d06c5
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