Microstructural Modeling and Simulation of a Carbon Black-Based Conductive Polymer─A Template for the Virtual Design of a Composite Material

Abstract

Carbon black is the most frequently applied conductive additive in rubber and polymer composites. In this work, we show how a carbon black microstructure in a polymer matrix can be conclusively modeled based on carbon black aggregation as well as an agglomeration mechanism using a state-of-the-art mathematical model. This novel and flexible microstructural modeling method enables us to virtually investigate the morphology of conductive additives within a polymer matrix and can be adapted to many conductive polymer combinations used for different applications. Furthermore, we calculate the electrical conductivity of the composite using a finite volume-based as well as a discrete element-based simulation technique and validate the results with experimental data. Utilizing a novel discrete element method (DEM) modeling technique, we were able to improve calculation times by a factor of 12.2 compared to finite volume method (FVM) simulations while maintaining high accuracy. Using this approach, we are able to predict the required carbon black content and minimize the amount of additive to create a polymer composite with a designated target conductivity.

Novel olive stone biochar particle network for piezoresistive strain sensing in natural fiber‐reinforced composites

“…The carbon particles used for unstable CB dispersion have a smaller particle size than the CB species in the stable dispersion as can be seen in Figure 7. This should work in favor of the smaller particle size 61–65 . The opposite trend is found.…”

“…They observed that smaller particles ( D = 40 nm vs. D = 250 nm) lead to better electrical conductivity at a similar volume fraction. For different aggregation sizes (19–90 nm particles) they did not find a trend due to positive and negative effects canceling each other out 65 . Intuitively one might think that a better distribution of particles should generally lead to a better electrical conductivity.…”

“…This should work in favor of the smaller particle size. [61][62][63][64][65] The opposite trend is found. This may be partly due to the different intrinsic conductivities of the particles.…”

“…For different aggregation sizes (19-90 nm particles) they did not find a trend due to positive and negative effects canceling each other out. 65 Intuitively one might think that a better distribution of particles should generally lead to a better electrical conductivity. The argument would be that aggregation and agglomeration cause isolated conductive islands with too large distances from each other to enable tunneling.…”

Polydopamine/Carbon Black/Carbon Nanofiber/Thermoplastic Polyurethane Composite Nanofiber Strain Sensor with Ultrahigh Loading Rate for Human Activity Monitoring

“…Figure g demonstrates the CNF/TPU obtained after anchoring the carbon nanofibers, that a large number of chopped CNFs are vertically anchored to the surface of the substrate fibers along the direction of solvent-induced force, and a stable high-density nanobrush structure is constructed based on the compatibility dispersion force between the two weakly polar materials, the mechanically interlocking structure generated by the swelling of the surface of the substrate fibers and combined with the directional repulsive effect of the strongly polar solvent environment, while a small number of CNFs are spanned across several fibers to form a sliding connecting bridge. Continued loading of CB in the form of grape cluster-like agglomerates tightly layered to fill the voids in the network structure of CNF to form a three-dimensional nanobrush-bridging structure, which drastically increases the density of conductive paths (Figure h) . The large loading of carbon nanomaterials resulted in more than 2-fold increase in the diameter of the composite fibers, demonstrating the effectiveness of the polarity-induced effect and the feasibility of employing mixed carbon fillers to construct an active functional layer.…”