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Modeling of Polymer/Ceramic Composites Properties
Published in Noureddine Ramdani, Polymer and Ceramic Composite Materials, 2019
The value of n parameter is related to both the polymer and the ceramic filler, thus decreasing the feasibility of the Lichtnecker equation for numerous materials [66]. In the EMT model, the dielectric property of the polymer/ceramic composite is taken as an effective medium whose relative permittivity is given by averaging the permittivity values of the composite components. This model is a self-consistent model that considers a random unit cell consisting of each filler particle covered by a concentric matrix layer.
Modeling nanomaterial physical properties: theory and simulation
Published in International Journal of Smart and Nano Materials, 2019
Tanujjal Bora, Adrien Dousse, Kunal Sharma, Kaushik Sarma, Alexander Baev, G. Louis Hornyak, Guatam Dasgupta
Effective medium approximations or theories (EMT) are capable of describing macroscopic properties of composite materials based on proportional blending of optical or electronic properties of components [20]. They are considered to be self-consistent, phenomenologically based continuum averaging techniques. Therefore, EMTs provide approximations of composite material behavior that are based on the relative volume fractions of its components [21]. EMT’s are rooted within classical physics, in particular, classical electromagnetic theories. In the middle of the 19th century, Ottavio-Fabrizio Mossotti (1850) developed the first form of the expression later to be modified by Rudolf Clausius (1879, the explicit form) to yield the well-known Clausius-Mossotti relationship – later to be embellished further by Ludvig Lorenz and Hendrik Lorentz (polarization leading to local field correction). The host medium was assumed to be vacuum or air in those expressions and mainly applicable for spherical particles or cavities. Today, numerical techniques based on discrete dipole approximations evolved from the Clausius-Mossotti relationship. These EMT homogenization techniques were based on classical and macroscopic constitutive relations derived from Maxwell’s equations [22]. Modern theories of polarization address computations of induced microscopic currents in condensed media by application of density functional theory [22,23].