I have measured electrical conductivity of my PMMA-based polymeric nanocomposites, and it doesn't fit the trend that with increasing concentrations electrical conductivity is increasing as well. I am saying doesn't fit the trend because here are used 2 fillers, 1D in combination with 2D, and when I have them in composites separately there is this trend. I received 24. 3 S/cm (2 wt.% of fillers), 23.7 S/cm (3.5 wt.% of fillers) and 20.7 S/cm (4 wt.% of fillers).
I know that for 4-point probe method the error can be up to 10%. So what is this number for BDS and what are the possible reasons of values decreasing?
Dear friend Anastasiia Stepura
The measurement error of BDS method can vary depending on the instrument and the specific experimental conditions. However, in general, the error is considered to be relatively low for most BDS measurements, on the order of 1-5%.
As for the possible reasons for the observed trend in your PMMA-based polymeric nanocomposites, there are several factors that could be contributing to the decrease in electrical conductivity with increasing filler concentration. These include:
1. Agglomeration of the fillers, which can create areas of low conductivity within the material.
2. Reduced mobility of the polymer chains due to interactions with the filler particles, which can hinder charge transport.
3. Formation of an insulating layer around the filler particles due to surface reactions or interactions with the surrounding polymer matrix.
To further investigate these factors, you may want to consider additional characterization techniques such as TEM, SEM, or XRD to examine the morphology and distribution of the filler particles within the polymer matrix, or impedance spectroscopy to probe the electrical properties of the material at different frequencies.
Here are some references that may be helpful for further reading on BDS and electrical conductivity measurements in polymers:
1. Jonsmann, J. (2018). Broadband Dielectric Spectroscopy. Springer International Publishing.
2. Kremer, F., & Schönhals, A. (Eds.). (2003). Broadband Dielectric Spectroscopy. Springer Berlin Heidelberg.
3. Rwei, S. P., Tsai, Y. C., & Tseng, T. T. (2010). Conductivity measurement of thin polymer films using the transmission-line method. Journal of Applied Polymer Science, 116(1), 340-346.
4. Kim, J. H., Lee, J. Y., Park, S. M., & Kim, S. S. (2016). Electrical conductivity of polymer composites filled with carbon black and multi-walled carbon nanotubes. Materials Letters, 164, 80-83.