skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Exact polarization energy for clusters of contacting dielectrics
The induced surface charges appear to diverge when dielectric particles form close contacts. Resolving this singularity numerically is prohibitively expensive because high spatial resolution is needed. We show that the strength of this singularity is logarithmic in both inter-particle separation and dielectric permittivity. A regularization scheme is proposed to isolate this singularity, and to calculate the exact cohesive energy for clusters of contacting dielectric particles. The results indicate that polarization energy stabilizes clusters of open configurations when permittivity is high, in agreement with the behavior of conducting particles, but stabilizes the compact configurations when permittivity is low.  more » « less
Award ID(s):
1846547
PAR ID:
10358274
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Soft Matter
Volume:
18
Issue:
34
ISSN:
1744-683X
Page Range / eLocation ID:
6411 to 6418
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; (, Polymers)
    null (Ed.)
    High permittivity polymer-ceramic nanocomposite dielectric films take advantage of the ease of flexibility in processing of polymers and the functionality of electroactive ceramic fillers. Hence, films like these may be applied to embedded energy storage devices for printed circuit electrical boards. However, the incompatibility of the hydrophilic ceramic filler and hydrophobic epoxy limit the filler concentration and therefore, dielectric permittivity of these materials. Traditionally, surfactants and core-shell processing of ceramic fillers are used to achieve electrostatic and steric stabilization for adequate ceramic particle distribution but, questions regarding these processes still remain. The purpose of this work is to understand the role of surfactant concentration ceramic particle surface morphology, and composite dielectric permittivity and conductivity. A comprehensive study of barium titanate-based epoxy nanocomposites was performed. Ethanol and 3-glycidyloxypropyltrimethoxysilan surface treatments were performed, where the best reduction in particle agglomeration, highest value of permittivity and the lowest value of loss were observed. The results demonstrate that optimization of coupling agent may lead to superior permittivity values and diminished losses that are ~2–3 times that of composites with non-optimized and traditional surfactant treatments. 
    more » « less
  2. ; ; ; ; ; (, Materials Today Physics)
    We developed ultra-high energy storage density capacitors using a new class of lead-free bismuth pyrochlorebased dielectric film material systems with high breakdown strength and reliability. The 2 μm-thick pyrochlore ceramic film capacitors have demonstrated ultra-high energy densities around 90 J/cm3 with very low energy loss below 3%, which is achieved by the combination of high permittivity, pseudo-linear dielectric characteristics, and high breakdown electric field over 4.5 MV/cm. Particularly, these pyrochlore ceramic films can endure voltage strength up to ~900 V. These noteworthy pyrochlore ceramic films are fabricated by the lowcost chemical solution deposition process which allows dielectric films to be processed on standard platinized silicon wafers. This new class of capacitors can satisfy the emergent needs for significant reduction in size and weight of capacitors with high energy storage capability in power electronics, electric vehicles, and energy storage in sustainable energy systems. Our research provides a unique and economical platform for the processing of this useful pyrochlore material in large volume for eco-friendly energy applications. 
    more » « less
  3. ; ; (, The Applied Computational Electromagnetics Society Journal (ACES))
    This paper presents a simulation-based study on the relative permittivity of 3D printed dielectric slabs printed with varying infill densities. In this study, a percentage volumetric model has been employed to model the infill density in a 3D printed dielectric slab. The relative permittivity of the filament material used to design the slab is assumed to be 2.45. The modeled slab is fitted into various rectangular waveguides with varying dimensions corresponding to different frequency ranges. As the infill density decreases, the relative permittivity of the dielectric slabs decreases. This lower value of relative permittivity is referred to as effective relative permittivity (εr.eff) throughout the paper. The study concludes that the effective relative permittivity of the slab decreases linearly as the infill density is decreased for the model. This study offers valuable insights into the effective relative permittivity of dielectric slabs under varying infill densities, providing implications for applications in areas such as antenna design. 
    more » « less
  4. ; ; (, SPIE 10968, Behavior and Mechanics of Multifunctional Materials XIII)
    Polymer nanocomposites exhibit unique effective properties that do not follow conventional effective media approaches. The nanoparticle-polymer interphase has been shown to strongly influence the nanocomposites behavior due o its significant volume when the particles are nano-sized, affording an opportunity to tune the dielectric response of the resulting nanocomposite. In this study, we investigate the effects of TiO2 nanoparticles on the electrical properties and the charges distribution and transport in polydimethylsiloxane (PDMS) nanocomposites. Impedance spectroscopy shows suppression of interfacial Maxwell-Wagner-Sillars (MWS) polarization accompanied by a reduction in the low frequency dielectric permittivity and loss at high temperatures in the presence of the TiO2 nanoparticles. Thermally stimulated discharge current measurements confirm that the suppression of the interfacial polarization relaxations happens by redistributing or depleting the charges through the composite and hindering their mobility, potentially resulting in lower electrical conduction and higher breakdown strength. Although the model materials investigated here are TiO2 nanoparticles and Sylgard 184 PDMS, our findings can be extended to other nanoparticulate-filled elastomer composites to design lightweight dielectrics, actuators and sensors with improved capabilities. 
    more » « less
  5. ; ; ; ; ; ; (, Applied Physics Letters)
    We report on temperature-dependent dielectric behavior of disordered ternary A6B2O17 (A = Zr, Hf; B = Nb, Ta)-form oxides in the GHz frequency range. The microwave dielectric properties including relative permittivity, dielectric loss, and temperature-dependent relative permittivity were characterized using cylindrical dielectric resonators using a resonant post measurement technique. Dielectric measurements through the resonant post method approach generally agree with dielectric measurements of A6B2O17 bulk ceramics measured through standard resonant post techniques. Coefficients describing the temperature-dependent relative permittivity for ternary A6B2O17 phases are strongly positive, suggesting contributions to polarizability arising from long-range mechanisms potentially associated with structural disorder. These observations support the working hypothesis that material functionality can be engineered by the chemical diversity and structural disorder possible in high configurational entropy A6B2O17 phases. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email