A precise numerical prediction of effective dielectric constant for polymer-ceramic composite based on effective-medium theory

Rao, Yang; Qu, Jianmin; Marinis, Thomas F.; Wong, Ching‐Ping

doi:10.1109/6144.888853

Cited by 242 publications

(23 citation statements)

References 6 publications

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“…can be explained considering smaller size of their BT used. As shown elsewhere, based on the results of a composite of polystyrene filled with BT nanoparticles and by using the effective medium theory, a slight enhancement of the dielectric constant is expected in the composite with larger interphase region or smaller the particles size . Besides, the Maxwell–Garnett approximation predicts an increase in the dielectric constant of the polymer of about 69% for a composition of 18.9% by volume of particles, which is very close to that experimentally obtained in this work.…”

Section: Resultssupporting

confidence: 90%

PVDF/BaTiO₃/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

González‐Benito

Olmos

Martínez-Tarifa

et al. 2019

J of Applied Polymer Sci

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Nanocomposites based on poly(vinylidene fluoride) (PVDF) filled with barium titanate, BaTiO 3 , (BT) particles, and multiwalled carbon nanotubes (MWCNTs) were prepared by high-energy ball milling (HEBM) and subsequent hot pressing. This method of materials preparation allowed obtaining uniform dispersions of the nanofillers. The influence of the particles on the polymer structure and morphology was studied. To understand the origin of changes in the PVDF properties, thermal and electrical behaviors of the PVDF/BT/MWCNT nanocomposites were studied as a function of composition. The addition of BT, MWCNT, or its mixture had not any influence on the PVDF polymorphism. However, calorimetric results pointed out that the presence of the nanofillers exerted nucleation mainly ascribed to the surface to volume ratio of the nanoparticles. The capacitance of the composites increased as the nanofiller content increased, being the effect mainly dependent on the surface to volume ratio of the nanoparticles. The dielectric behavior of the materials as a function of frequency was modeled by a Debye equivalent circuit only below the percolation threshold respect to the amount of MWCNT. The piezoelectric behavior of the ternary nanocomposites was highly affected by the incorporation of the nanofillers only when high dielectric losses occurred above the percolation threshold.

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Section: Resultssupporting

confidence: 90%

PVDF/BaTiO₃/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

González‐Benito

Olmos

Martínez-Tarifa

et al. 2019

J of Applied Polymer Sci

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“…In recent studies, the theoretical ε r of polymer‐based composites have been predicted by a lot of mathematic models, such as Jayasundere–Smith equation, Lichtenecker equation, Maxwell–Wagner equation, and Effective Medium Theory . The most famous and commonly used model is Lichtenecker logarithmic law of mixing.…”

Section: Resultsmentioning

confidence: 99%

Medium dielectric constant and low‐loss PTFE composites filled with MgO‐LiF co‐doped Li₂TiO₃ particles

Wang

Tong³

et al. 2019

J of Applied Polymer Sci

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In this work, we presented a simple strategy to fabricate medium dielectric constant and low-loss composites for microwave substrate applications. MgO-LiF co-doped Li 2 TiO 3 (LT) powders were fabricated by the solid-state reaction route and modified by perfluorooctyltriethoxysilane (F8261). The LT/polytetrafluoroethylene (PTFE) composites were fabricated by cold pressing and hot treatment. The XPS and contact angle analysis indicated that the fluorinated group was introduced to LT particle successfully. The effects of modified LT powders content on the dielectric, thermal, and mechanical properties of composites were investigated. As the modified LT content increases, the dielectric constant, dielectric loss, and temperature coefficient of dielectric constant (τ ε ) increase while the bending strength and coefficient of thermal expansion (CTE) decrease, which is attributed to the higher dielectric constant of LT ceramic, more pores, stable τ ε of LT ceramic, interface defects and low CTE of LT ceramic, respectively. The composites with 60 wt % LT exhibit the best microwave dielectric properties: ε r = 6.8, tanδ = 0.001, τ ε = −29.6 ppm C −1 at 8 GHz and acceptable coefficient of thermal expansion (28.3 ppm C −1 ). Therefore, modified LT powders filled PTFE composites are potential materials for high-frequency microwave substrate applications.

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“…2 The photonic band gap map as a function of the dielectric constant of embedding material. TE and TM band maps are the same in this case to be 0.13 according to Yang's experiment (Yang et al 2000). The effective dielectric constant of the mixture of barium titanate powder and epoxy varies with the volume fraction, m 2 .…”

Section: Design and Analysismentioning

confidence: 98%

“…Epoxy (ARALDITE LY564, from Ciba-Geigy) will be used to bind the barium titanate particles in the mixture material. The tetragonality, density, and particle size of barium titanate powder may affect its dielectric constant (Wada et al 2003;Zhe et al 2004;Xie et al 2005;Tsurumi et al 2006;Yang et al 2000). The dielectric constant of barium titanate powder (from Alfa Aesar) with particle size 50-70 nm is estimated to be 1,100.…”

Section: Design and Analysismentioning

confidence: 99%

Fabrication of the plastic component for photonic crystal using micro injection molding

Chang

Young

2010

Microsyst Technol

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In this decade, many techniques have been introduced to fabricate photonic crystal in optical applications. Most of the processes used to fabricate the photonic crystal are time consuming and not cost effective. This study demonstrates an efficient method to fabricate photonic crystals. A polymer-based photonic crystal slab has been developed by embedding mixture with a high dielectric constant. Photonic crystals have patterned structures in which periodicity of dielectric properties can manipulate electromagnetic waves. The operation wavelength is about half of the characteristic dimension. Technique of injection molding is applied to make polymer parts with the photonic crystal pattern. Then mixture of barium titanate powder and epoxy is embedded on the patterned structure of the polymer part. The contrast of dielectric coefficients between mixture and polymer can constitute a structure with some photonic band gap. By means of polymer processing, mass production of photonic crystal devices like optical switch, optical waveguide, optical filter and so forth can be realized in a cost effective way.

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A precise numerical prediction of effective dielectric constant for polymer-ceramic composite based on effective-medium theory

Cited by 242 publications

References 6 publications

PVDF/BaTiO₃/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

PVDF/BaTiO₃/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

Medium dielectric constant and low‐loss PTFE composites filled with MgO‐LiF co‐doped Li₂TiO₃ particles

Fabrication of the plastic component for photonic crystal using micro injection molding

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A precise numerical prediction of effective dielectric constant for polymer-ceramic composite based on effective-medium theory

Cited by 242 publications

References 6 publications

PVDF/BaTiO3/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

PVDF/BaTiO3/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

Medium dielectric constant and low‐loss PTFE composites filled with MgO‐LiF co‐doped Li2TiO3 particles

Fabrication of the plastic component for photonic crystal using micro injection molding

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Product

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PVDF/BaTiO₃/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

PVDF/BaTiO₃/carbon nanotubes ternary nanocomposites prepared by ball milling: Piezo and dielectric responses

Medium dielectric constant and low‐loss PTFE composites filled with MgO‐LiF co‐doped Li₂TiO₃ particles