Microstructure-based numerical modeling method for effective permittivity of ceramic/polymer composites

Jylhä, Liisi; Honkamo, Johanna; Jantunen, Heli; Sihvola, Ari

doi:10.1063/1.1897071

Cited by 39 publications

(23 citation statements)

References 18 publications

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“…Barium titanate's great significance is expressed in its applications, which include ceramic capacitors, PTCR thermistors (positive temperature coefficient resistors/thermistors or posistors), piezoelectric sensors, optoelectronic devices, transducers, actuators etc. [4][5][6][7][8][9][10]. Furthermore, it is being applied as a capacitive material in dynamic random access memories (DRAM) in integrated circuits.…”

mentioning

confidence: 99%

Barium titanate/polyester resin nanocomposites: Development, structure-properties relationship and energy storage capability

Asimakopoulos¹,

Psarras²,

Zoumpoulakis³

2014

Express Polym. Lett.

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Abstract. Nanocomposite materials based on two different types of polyester matrix (a commercial type and a laboratory produced one) with embedded barium titanate nano-particles were developed and characterized. Structural and morphological characteristics of the produced composite specimens were studied via X-ray diffraction, Fourier transformation infra red spectroscopy, and scanning electron microscopy. Thermal, mechanical and electrical performance was examined via differential scanning calorimetry, bending and shear strength tests, and broadband dielectric spectroscopy, respectively. Mechanical strength appears to reduce with the increase of filler content. Commercial polyester's composites exhibit brittle behaviour, while laboratory polyester's composites exhibit an elastomeric performance. Dielectric data reveal the presence of four relaxation processes, which are attributed to motion of small parts of the polymer chain (!-mode), re-arrangement of polar side groups ("-mode), glass to rubber transition of the polymer matrix (#-mode) and Interfacial Polarization between the systems' constituents. Finally, the energy storing efficiency of the systems was examined by calculating the density of energy. Vol.8, No.9 (2014) 692-707 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2014.72 * Corresponding author, e-mail: G.C.Psarras@upatras.gr © BME-PT An outstanding position in the group of electroceramics is given to composite materials based on barium titanate. Barium titanate is a wide band gap semiconductive ferroelectric material with perovskite structure which has been of practical importance for over 60 years due to its specific electrical properties. Barium titanate's great significance is expressed in its applications, which include ceramic capacitors, PTCR thermistors (positive temperature coefficient resistors/thermistors or posistors), piezoelectric sensors, optoelectronic devices, transducers, actuators etc. [4][5][6][7][8][9][10]. Furthermore, it is being applied as a capacitive material in dynamic random access memories (DRAM) in integrated circuits. DRAM applications require both high dielectric constant and good insulating properties [10]. Semiconductor memories such as dynamic random access memories (DRAM's) and static random access memories (SRAM's) currently dominate the market. However, the disadvantage of these memories is that they are volatile, i.e. the stored information is lost when the power fails. The non-volatile memories available at this time include complementary metal oxide semiconductors (CMOS) with battery backup and electrically erasable read only memories (EEPROM's). These non-volatile memories are very expensive. The main advantages offered by ferroelectric random access memories (FRAM's) include non-volatility and radiation hardened compatibility with CMOS and GaAs circuitry, high speed (30ns cycle time for read/erase/rewrite) and high density (4 (µm) 2 /cell size) [11]. Up to now, the most important utility of BaTiO 3 / polymer composites is ...

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confidence: 99%

Barium titanate/polyester resin nanocomposites: Development, structure-properties relationship and energy storage capability

Asimakopoulos¹,

Psarras²,

Zoumpoulakis³

2014

Express Polym. Lett.

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“…Epoxy resin was employed as the polymer matrix, due to its stable thermomechanical properties, resistance to corrosive environments, ease of processing and attractive adhesive nature that allows the hosting of various fillers [18][19][20]. Furthermore, titanium dioxide (TiO 2 ) particles were chosen as the ceramic filler, mainly due to the fact that TiO 2 -based composites have been proven excellent candidates for use in a wide range of applications, including integrated decoupling capacitors, angular acceleration accelerometers, acoustic emission sensors, and electronic packaging [21][22][23][24]. To the best of our knowledge,only one previous study exists on the dielectric properties of polymer-TiO 2 composites [23].…”

Section: Introductionmentioning

confidence: 99%

Electrical characterization of polymer matrix — TiO2 filler composites through isothermal polarization / depolarization currents and I–V tests

2014

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Abstract:Specimens of polymer matrix -ceramic TiO 2 filler composites were prepared. The contribution of the filler content on the electrical conductivity and energy storage properties of the samples was examined. I-V and Isothermal Polarization/Depolarization Current (IPC/IDC) measurements were conducted. Dc conductivity values directly calculated from the I-V curves exhibited excellent agreement with corresponding values derived from the IPC/IDC recordings. Standard models were employed for fitting the IPC/IDC data. In specific, the short and the very long depolarization times were fitted by use of power laws of different slopes, while the intermediate depolarization times were fitted as a sum of three exponential decays. The present study reveals a strong dependence of the depolarization and polarization processes, as well as of the dc conductivity, on the filler concentration.

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“…Such composites include particle-, fiber-, and whisker-reinforced polymers and ceramics; photonic crystals; metamaterials; piezoelectric polymer foams and polymerceramic composites; multifunctional materials combining structural, sensing, actuating, and selfrepair capabilities; and nanoscale electronic materials such as magnetoelectric nanocomposites, carbon nanotube composites, and spintronic materials. [14][15][16] Having accurate models for the effective permittivity of random media is also critical for the nondestructive evaluation or process monitoring of composites and mixtures using capacitance measurements, impedance spectroscopy, and microwave methods. 17,18 In biological media, dielectric spectroscopy has been used to measure the effective permittivity of cell suspensions and tissues to characterize properties such as yeast cell morphology and cell division.…”

Section: Introductionmentioning

confidence: 99%

“…Several FE models have calculated the permittivity of composites and mixtures by applying periodic boundary conditions to a square or cubic unit cell containing a small number (1-134) of circular, [31][32][33][34][35] spherical, 31 or prismatic inclusions. 16 FE calculations have also been combined with the method of boundaryintegral equations (BIE) to simulate single inclusions of various shapes, including ellipsoids and cylinders, in 2D and 3D unit cells. 14 Similarly, the FDTD method has been used to model 2D mixtures containing up to 265 inclusions (1.0 inclusion volume fraction), 36,37 and to model the EM properties of biological tissues using periodic stacks of 30-100 spherical cells; 21 Other 6 approaches used to model the permittivity of random media include the transmission line matrix (TLM) method, which was applied to 2D simulations of 64-127 inclusions in a square periodic unit cell (0.5-1.0 inclusion volume fraction), 38 and the lattice Boltzmann method, which used 2D simulations to model fluid aggregation (wetting) in multiphase microporous materials.…”

Section: Introductionmentioning

confidence: 99%

Effects of aggregation on the permittivity of random media containing monodisperse spheres

Doyle

Tew

Jain

et al. 2009

Journal of Applied Physics

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The NERC and CEH trade marks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. AbstractNumerical simulations were used to calculate the effective permittivities of three-dimensional random particle suspensions containing up to 2440 particles and exhibiting two types of particle aggregation. The particles were modeled as 200-µm spheres that were aggregated into either large spherical clusters or into foam-type microstructures with large spherical voids. Multiple scattering of 0.01-10.0 GHz electromagnetic fields was simulated using a first-principles iterative multipole approach with matrix and particle permittivities of 1.0 and 8.5, respectively.The computational results showed both significant and highly significant trends. Aggregation 2 into spherical clusters decreased the effective permittivity by up to 3.2 ± 0.2%, whereas aggregation into foam-type microstructures increased the effective permittivity by up to 3.0 ± 1.6%. The effective permittivity trends exhibited little change with frequency. These results were compared to effective medium approximations that predicted higher permittivities than those from the simulations and showed opposite trends for cluster aggregation. Three theories are proposed to explain the simulation results. The first theory invokes a waveguide-like mechanism. The simulations indicate that the wave fields propagate more through the continuous paths of greater or lesser particle density created by aggregation, rather than through the isolated particle clusters or large voids. This quasi-continuous phase, or quasi-matrix, therefore behaves like a random waveguide structure in the material. A second theory is proposed where the quasicontinuous phase governs the behavior of the system by a percolation-like process. In this theory, the multipole interactions are modeled as the percolation of virtual charges tunneling from one particle to another. A third mechanism for the permittivity changes is also proposed involving collective polarization effects associated with the particle clusters or large voids. The simulation results challenge the general applicability of the quasistatic limit for heterogeneous media by showing how microstructural changes much smaller than the electromagnetic wavelength can alter the effective permittivity by a statistically significant degree. The results also provide a quantitative indication of the effects of aggregation and hierarchical microstructures on the electromagnetic properties of random media, and have application to the remote and in situ sensing of soils, the rational design and nondestructive evaluation of composites, and the study of biological tissues and other random materials.3

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Microstructure-based numerical modeling method for effective permittivity of ceramic/polymer composites

Abstract: Finite-element modeling method for the prediction of the complex effective permittivity of two-phase random statistically isotropic heterostructures

Cited by 39 publications

References 18 publications

Barium titanate/polyester resin nanocomposites: Development, structure-properties relationship and energy storage capability

Barium titanate/polyester resin nanocomposites: Development, structure-properties relationship and energy storage capability

Electrical characterization of polymer matrix — TiO2 filler composites through isothermal polarization / depolarization currents and I–V tests

Effects of aggregation on the permittivity of random media containing monodisperse spheres

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