I m working on polymer composites and enhancing their conductivity by using fillers and comparing their conductivity and dielectric constant values.
if you want to correlate conductivity to dielectric constant, you need to know the loss factor of your material as well.
σ = ω εo ε' tan δ
where ω is the angular frequency and εo = 8.85 x 10-12 F m-1, tan δ = ε''/ε'.
If you provide more details/information about your project, it may exists different approach to follow.
Hope this helps.
Juliano
In principle, they are independent (i.e. ohmic conductivity and permittivity) but in practice, due to disperisve transport and electrode plarization they are frequently iner-related, especially in composites where you also have interfacial polarization at the filler/matrix inerface.
The expression is already given above in another response. It will give you frequency dependent conductivity. You can fit it by Jonscher's power law (See appropriate literature for the same). The conduction will lead to dielectric losses which will influence the dielectric permittivity of your sample.
Dear Farrukh
Frequency dependent conductivity can be observed when polarisation does not follow a.c. field. This is the situation where dielectric loss occurs.There may be a situation where dielectric loss is negligible at frequencies much lower or much higher than relaxation frequency but dielectric constant will be significant due to electric polarisation. Hence, in principle, a.c conductivity and dielectric constant both are independent of each other. D. C. conductivity has also no direct relation on dielectric constant.
A.Kumar
In general, you do not have enough information to do this. A material's permittivity and its conductivity are fundamentally different quantities, and cannot generally be calculated from one another, particularly if all you have are static measurements.
Khalid Mujasam Batoo Thanks for sharing this kind of research paper.
Dear Farrukh Bashir ,
Because the importance of this question as it concerns the basic properties of the materials, it motivates me to answer it.
If you speak about materials at low frequencies such that no polarization losses occur, then what you measure here is the real part of the dielectric consatnt and also you measure the conductivity of the material due to movement of the free charge carriers in the material.
By changing the composition of the material both the conductivity sigma and the real dielectric constant both cab be changed or one of them. In organic materials it is very probable that both change but if the added material is a doping material its very probable that the conductivity changes more than the epsilon by doping.
The conductivity changes because of bonding pattern change leading to creation of free holes or electrons. While the change in epsilon is because the added molecules has different polarization than the host molecules.
Best wishes
Hi Farrukh Bashir, thank you for asking this technical question. AC conductivity is determined by dielectric loss factor. To enhance AC conductivity of the material, you should raise its dielectric loss factor as well. AC conductivity is frequency dependence. May I know you wish to enhance the conductivity at which frequency?
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