Dielectric behavior of polyelectrolyte solutions: the role of proton fluctuation

1991 ◽  
Vol 95 (12) ◽  
pp. 4883-4889 ◽  
Author(s):  
F. Bordi ◽  
C. Cametti ◽  
G. Paradossi
Keyword(s):  
Dielectric Behavior ◽  
Polyelectrolyte Solutions

Grain Boundary Segregation in Titanium Dioxide: Evaluation of Relative Driving Forces for Segregation

2002 ◽  
Vol 751 ◽  
Author(s):  
Qinglei Wang ◽  
Guoda D. Lian ◽  
Elizabeth C. Dickey
Keyword(s):  
Titanium Dioxide ◽  
Driving Forces ◽  
Boundary Segregation ◽  
Solute Segregation ◽  
Dielectric Behavior ◽  
Relative Role ◽  
Transmission Electron ◽  
Fundamental Phenomenon ◽  
Versus Strain

ABSTRACTSolute segregation to grain boundaries is a fundamental phenomenon in polycrystalline metal-oxide electroceramics that has enormous implications for the macroscopic dielectric behavior of the materials. This paper presents a systematic study of solute segregation in a model dielectric, titanium dioxide. We investigate the relative role of the electrostatic versus strain energy driving forces for segregation by studying yttrium-doped specimens. Through analytical transmission electron microscopy studies, we quantitatively determine the segregation behavior of the material. The measured Gibbsian interfacial excesses are compared to thermodynamic predictions.

Transport Properties of Polyelectrolyte Solutions. Effect of Confinement in Thin Liquid Films

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Jérôme Delacotte ◽  
Dominique Langevin
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Conductivity Measurements ◽  
Polyelectrolyte Solutions

AbstractThe role of condensed counterions in transport properties, such as electrical conductivity and viscosity, has been investigated with solutions of a flexible polyelectrolyte. Comparisons with existing theories are proposed. Viscosity is strongly affected by confinement in thin films, depending whether polyelectrolyte chains are adsorbed or not at the film surfaces. The role of counterion mobility is however difficult to assess because the measurements are not accurate enough. It is proposed that this role could be tested by electrical conductivity measurements.

Role of grain boundaries in the dielectric behavior of graphite

Carbon ◽  
2021 ◽  
Vol 173 ◽  
pp. 1003-1019 ◽  
Author(s):  
Xiang Xi ◽  
D.D.L. Chung
Keyword(s):  
Grain Boundaries ◽  
Dielectric Behavior

scholarly journals Dependence of Lattice Distortion and Dielectric Response of Zinc Aluminate on Milling Frequency

2018 ◽  
Vol 778 ◽  
pp. 217-224
Author(s):  
Hadia Noor ◽  
Saira Riaz ◽  
Malik Maryyam Iram ◽  
Amna Siddiqi ◽  
Shahzad Naseem
Keyword(s):  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Dielectric Behavior ◽  
Zinc Aluminate ◽  
Leading Role ◽  
Potential Applications ◽  
Nyquist Plots ◽  
Scherrer Formula ◽  
Grain Bulk

Zinc aluminate (ZnAl2O4) samples were prepared using nanomilling based solid state reaction method for several potential applications. Effect of milling frequency on structural and dielectric behavior of ZnAl2O4 has been explored systemically. Investigation of crystal structure reveals that change in lattice parameter by milling does not alter the cubic lattice of ZnAl2O4. This milling frequency at the nanosize resulted in a gradual decrease in the particle size, which can be attributed to the inhomogeneous defects. Grain size in nanometers has been calculated by XRD using Debye-Scherrer formula. Dielectric measurements performed in the range of 20Hz-20MHz confirms the Maxwell –Wagner two layer model which is consistent with the Koop’s theory. High value of ac conductivity indicates that milling blocked the ionic transport. As a result of Nyquist plots, a single semicircle was obtained which indicated the leading role of grain (bulk). The variation in the semicircle radii for different samples is due to the influence of milling frequency.

scholarly journals Electroactive γ-Phase, Enhanced Thermal and Mechanical Properties and High Ionic Conductivity Response of Poly (Vinylidene Fluoride)/Cellulose Nanocrystal Hybrid Nanocomposites

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 743
Author(s):  
Erlantz Lizundia ◽  
Ander Reizabal ◽  
Carlos M. Costa ◽  
Alberto Maceiras ◽  
Senentxu Lanceros-Méndez
Keyword(s):  
Ionic Conductivity ◽  
Vinylidene Fluoride ◽  
Mechanical Performance ◽  
Dielectric Behavior ◽  
Hybrid Nanocomposites ◽  
Thermal And Mechanical Properties ◽  
Oh Groups ◽  
Poly Vinylidene Fluoride ◽  
Relevant Role

Cellulose nanocrystals (CNCs) were incorporated into poly (vinylidene fluoride) (PVDF) to tailor the mechanical and dielectric properties of this electroactive polymer. PVDF/CNC nanocomposites with concentrations up to 15 wt.% were prepared by solvent-casting followed by quick vacuum drying in order to ensure the formation of the electroactive γ-phase. The changes induced by the presence of CNCs on the morphology of PVDF and its crystalline structure, thermal properties, mechanical performance and dielectric behavior are explored. The results suggest a relevant role of the CNC surface −OH groups, which interact with PVDF fluorine atoms. The real dielectric constant ε’ of nanocomposites at 200 Hz was found to increase by 3.6 times up to 47 for the 15 wt.% CNC nanocomposite due to an enhanced ionic conductivity provided by CNCs. The approach reported here in order to boost the formation of the γ-phase of PVDF upon the incorporation of CNCs serves to further develop cellulose-based multifunctional materials.

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