In insulating polymers with low or high degree of crystallinity, if a conductive nanoparticle is added,will the electrical conductivity of the composite depend on the degree of crystallinity of the polymer?
Will a high degree of crytallinity lead to a high electrical conductivity?and how?
It is correct that crystallinity affects conductivity. Increased crystallinity will enhance conductivity due to higher order. Conducting nanoparticles are expected to sit in between the crystalline zones and there will be better regularity in conduction mechanism.
Thank you dr Samui.
Yes,exactly! In most cases the (ionic) conductivity of the amorphous phase is higher than that of the crystalline phase. Therefore more crystalline polymers exhibit usually lower conductivity. The addition of conductive nanoparticles (e.g carbon nanotubes) increases the conductivity but only above the percolation threshold where the nanoparticles contact each other and form a conducting network. The nanoparticles tend to concentrate in the amorphous (inter.crystalline) phase, so it may happen that the percolation occurs at lower concentration if the matrix polymer exhibits higher crystallinity.
The beauty this electrical conductivity is the crystalline phase have better conductivity than amorphous in conjugated polymers. If you added any electrical conductivity additive. The additive will go and set in the amorphous phase.
Hello, I have been mixing PLLA with carbon nanotube several years ago followed annealing at various temperature. The enhancement of the conductivity was not so clear and it seemed to depend on crystallinity content and crystallites shapes. Usually, conductiviy increased with the crystallinity extent due to an enrichment of the amorphous phase in CNT. However, for specific conditions, percolation threshold increased and electrical conductivity no longer appears. I did not make more expriments but i think that the morphology of amorphous phase play a key role ...
I had some experiments about crystallinity effect on dielectric properties. Crystallinity changes the morphology, structure, thermal properties, and dielectric properties etc. You can find some of them in my profile. I haven’t published all of them.
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