Broadband dielectric spectroscopy studies of glassy-state relaxations in annealed poly(2,5-benzimidazole)

2011 ◽  
Vol 61 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Amol Nalawade ◽  
Mohammad K. Hassan ◽  
William A. Jarrett ◽  
Kenneth A. Mauritz ◽  
Morton H. Litt
Keyword(s):  
Dielectric Spectroscopy ◽  
Glassy State ◽  
Broadband Dielectric Spectroscopy ◽  
Spectroscopy Studies

Broadband Dielectric Spectroscopy Studies of Hyperbranched Polyglycerols

2006 ◽  
Vol 207 (11) ◽  
pp. 970-977 ◽  
Author(s):  
Abel Garcia-Bernabé ◽  
Ricardo Díaz-Calleja ◽  
Rainer Haag
Keyword(s):  
Dielectric Spectroscopy ◽  
Broadband Dielectric Spectroscopy ◽  
Spectroscopy Studies

scholarly journals Kinetics of Non-Isothermal and Isothermal Crystallization in a Liquid Crystal with Highly Ordered Smectic Phase as Reflected by Differential Scanning Calorimetry, Polarized Optical Microscopy and Broadband Dielectric Spectroscopy

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 205 ◽  
Author(s):  
Małgorzata Jasiurkowska-Delaporte ◽  
Tomasz Rozwadowski ◽  
Ewa Juszyńska-Gałązka
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Microscopy ◽  
Dielectric Spectroscopy ◽  
Isothermal Crystallization ◽  
Glassy State ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Broadband Dielectric Spectroscopy ◽  
Kinetics Of

The kinetics of the non-isothermal and isothermal crystallization of the crystalline smectic B phase (soft crystal B, SmBcr) in 4-n-butyloxybenzylidene-4′-n′-octylaniline (BBOA) was studied by a combination of differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and polarized optical microscopy (POM). On cooling, part of the SmBcr phase undergoes conversion to a crystalline phase and the remainder forms a glassy state; after the glass softens, crystallization is completed during subsequent heating. By analyzing the area of the crystal growing in the texture of SmBcr as a function of time, the evolution of degree of crystallinity, D(t), was estimated. It was demonstrated that upon heating, D(t) follows the same Avrami curve as the crystallization during cooling. Non-isothermal crystallization observed during slow cooling rates (3K/min ≤ ϕ ≤ 5K/min) is a thermodynamically-controlled process with the energy barrier Ea ≈ 175 kJ/mol; however, the crystallization occurring during fast cooling (5 K/min > ϕ ≥ 30K/min) is driven by a diffusion mechanism, and is characterized by Ea ≈ 305 kJ/mol. The isothermal crystallization taking place in the temperature range 274 K and 281 K is determined by nucleus formation.

scholarly journals TSC and Broadband Dielectric Spectroscopy Studies of the α Relaxation in Phosphorus-Containing Dendrimers

2004 ◽  
Vol 37 (8) ◽  
pp. 2812-2816 ◽  
Author(s):  
E. Dantras ◽  
J. Dandurand ◽  
C. Lacabanne ◽  
A. M. Caminade ◽  
J. P. Majoral
Keyword(s):  
Dielectric Spectroscopy ◽  
Broadband Dielectric Spectroscopy ◽  
Phosphorus Containing ◽  
Spectroscopy Studies

scholarly journals Broadband dielectric spectroscopy for monitoring temperature-dependent chloride ion motion in BiOCl plates

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adrian Radoń ◽  
Dariusz Łukowiec ◽  
Patryk Włodarczyk
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Spectroscopy ◽  
Low Frequency ◽  
Chloride Ion ◽  
Ion Source ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Broadband Dielectric Spectroscopy ◽  
Free Chloride ◽  
Structure Rebuilding

AbstractThe dielectric properties and electrical conduction mechanism of bismuth oxychloride (BiOCl) plates synthesized using chloramine-T as the chloride ion source were investigated. Thermally-activated structure rebuilding was monitored using broadband dielectric spectroscopy, which showed that the onset temperature of this process was 283 K. This rebuilding was related to the introduction of free chloride ions into [Bi2O2]2+ layers and their growth, which increased the intensity of the (101) diffraction peak. The electrical conductivity and dielectric permittivity were related to the movement of chloride ions between plates (in the low-frequency region), the interplanar motion of Cl− ions at higher frequencies, vibrations of these ions, and charge carrier hopping at frequencies above 10 kHz. The influence of the free chloride ion concentration on the electrical conductivity was also described. Structure rebuilding was associated with a lower concentration of free chloride ions, which significantly decreased the conductivity. According to the analysis, the BiOCl plate conductivity was related to the movement of Cl− ions, not electrons.

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