Effect of graphitic filler size and shape on the microstructure, electrical percolation behavior and thermal properties of nanostructured multilayered carbon films deposited onto paper substrates

Abstract

Dispersions containing 1 mg/mL of several carbon nanomaterials were used to deposit films containing 1 to 20 layers. The electrical properties of the composite films were characterized via impedance spectroscopy along two directions: in-plane on the film topmost surface and also through the thickness. It was found that carbon black nanoparticles never achieved full in-plane interconnection while the multiwalled carbon nanotube (MWNT) and single-walled carbon nanotube were already percolated at one layer. Graphite flakes showed a complete percolation curve that allowed its resistance to change by 6-7 orders of magnitude. The differences in the microstructure, electrical response, and thermal decomposition behavior of these carbon nanomaterial-paper substrate films were explained by detailed equivalent circuit analysis of the impedance spectra. Interpretation was supplemented by scanning electron microscopy images and thermal analysis via Differential Scanning Calorimetry/Thermogravimetric Analysis (DSC/TGA). Thru-plane electrical properties were for the most part similar, although only films with short MWNT showed a clearly infiltrated network structure.

Mechanical and electrical properties of low SWNT content 3YTZP composites

“…5(a)) similar to the described one by previous authors, 37,41 consisting of a R-C element connected in series with a R-CPE (constant phase element). The CPE is generally used to represent a distribution of relaxation times.…”

Microstructure and impedance spectroscopy of 3YTZP/SWNT ceramic nanocomposites

“…In this context, when modelling the impedance properties of a ceramic composite with a SWNT percolated network, an equivalent circuit model consisting of two R-C elements in series describes suitably the conduction through SWNT junctions and bundles. 17,25,26 It has been established by different authors that the resistance across junctions is higher than the resistance through the carbon nanotube bundles themselves. [27][28][29] Thus, the lower resistance element will be assigned to the SWNT bundles and the higher resistance one will be assigned to the junctions between bundles.…”

Percolation in Borosilicate Glass Matrix Composites Containing Antimony‐Doped Tin Oxide Segregated Networks. Part II: Examination of Electrical Behavior Using Impedance Spectroscopy

“…Although contact resistance could be contributing to this inductance, this typically occurs in highly conductive samples and at lower frequencies than what was observed here so it is more likely this is being caused by the ATO network . The detection of such a response is indicative of a network that is fully developed in three dimensions in the composite . In addition, if this inductive response was to be caused by a contact resistance then it would appear on all the samples and not just the high concentration ones.…”