scholarly journals Relaxation modes of metaphosphate glasses with entropic shrinkage

AIP Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 095222
Author(s):  
Takatoshi Yaoita ◽  
Seiji Inaba
Keyword(s):  
Relaxation Modes

scholarly journals On the Mutual Relationships between Molecular Probe Mobility and Free Volume and Polymer Dynamics in Organic Glass Formers: cis-1,4-poly(isoprene)

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 294
Author(s):  
Helena Švajdlenková ◽  
Ondrej Šauša ◽  
Sergey V. Adichtchev ◽  
Nikolay V. Surovtsev ◽  
Vladimir N. Novikov ◽  
...  
Keyword(s):  
Free Volume ◽  
Spin Probe ◽  
Hyperfine Coupling Constant ◽  
Organic Glass ◽  
Molecular Probe ◽  
Positron Annihilation Lifetime ◽  
Broadband Dielectric Spectroscopy ◽  
Relaxation Modes ◽  
Reorientation Dynamics ◽  
In Cis

We report on the reorientation dynamics of small spin probe 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) in cis-1,4-poly(isoprene) (cis-1,4-PIP10k) from electron spin resonance (ESR) and the free volume of cis-1,4-PIP10k from positron annihilation lifetime spectroscopy (PALS) in relation to the high-frequency relaxations of cis-1,4-PIP10k using light scattering (LS) as well as to the slow and fast processes from broadband dielectric spectroscopy (BDS) and neutron scattering (NS). The hyperfine coupling constant, 2Azz′(T), and the correlation times, τc(T), of cis-1,4-PIP10k/TEMPO system as a function of temperature exhibit several regions of the distinct spin probe TEMPO dynamics over a wide temperature range from 100 K up to 350 K. The characteristic ESR temperatures of changes in the spin probe dynamics in cis-1,4-PIP10k/TEMPO system are closely related to the characteristic PALS ones reflecting changes in the free volume expansion from PALS measurement. Finally, the time scales of the slow and fast dynamics of TEMPO in cis-1,4-PIP10k are compared with all of the six known slow and fast relaxation modes from BDS, LS and NS techniques with the aim to discuss the controlling factors of the spin probe reorientation mobility in polymer, oligomer and small molecular organic glass-formers.

scholarly journals Effect of a Dc Oblique Magnetic Field on the Magnetic Susceptibility of the Super-Paramagnetics Nanoparticles in Very Low Damping

2020 ◽  
pp. 1-3
Author(s):  
Malika MADANI ◽  
◽  
Bachir OUARI ◽  
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Transverse Relaxation ◽  
Damping Parameter ◽  
Complex Susceptibility ◽  
Relaxation Modes ◽  
Oblique Field ◽  
Arbitrary Amplitude ◽  
Matrix Continued Fraction ◽  
Oblique Magnetic Field

The Magnetic Susceptibility of an individual Super-Paramagnetic nanoparticle in a presence of DC Oblique magnetic fields of arbitrary amplitude is investigated using Brown’s continuous diffusion model. The susceptibility is calculated and compared when for extensive ranges of the anisotropy, the dc magnetic fields in the very low damping with Matrix continued Fraction. It is shown that the shape of the Spectrum of Super-Paramagnetic nanoparticles is substantially altered by applying a dc oblique field. There is also an inherent geometric dependence of the complex susceptibility on the damping parameter arising from coupling of longitudinal and transverse relaxation modes

Effect of dye dispersion on the relaxation modes of smectic C* phase

2013 ◽  
Vol 40 (11) ◽  
pp. 1503-1511 ◽  
Author(s):  
Satya Prakash Yadav ◽  
Mukti Pande ◽  
Rajiv Manohar ◽  
Shri Singh
Keyword(s):  
Smectic C ◽  
Relaxation Modes

Crossover from local to collective magnetic relaxation modes in Co/Ni multilayers

2002 ◽  
Vol 242-245 ◽  
pp. 518-520
Author(s):  
J.M. González ◽  
A. Salcedo ◽  
F.J. Palomares ◽  
F. Cebollada ◽  
C. Prados ◽  
...  
Keyword(s):  
Magnetic Relaxation ◽  
Relaxation Modes

scholarly journals Complex Temperature and Concentration Dependent Self-Assembly of Poly(2-oxazoline) Block Copolymers

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1495 ◽  
Author(s):  
Loan Trinh Che ◽  
Marianne Hiorth ◽  
Richard Hoogenboom ◽  
Anna-Lena Kjøniksen
Keyword(s):  
High Temperatures ◽  
Self Assembly ◽  
Low Temperatures ◽  
Polymer Concentration ◽  
Random Copolymer ◽  
Polymer Chains ◽  
Relaxation Modes ◽  
Self Association ◽  
Copolymer Structure ◽  
Complex Temperature

The effect of polymer concentration on the temperature-induced self-association of a block copolymer comprising a poly(2-ethyl-2-oxazoline) block and a random copolymer block consisting of 2-ethyl-2-oxazoline and 2-n-propyl-2-oxazoline (PEtO80-block-P(EtOxx-stat-PropO40-x) with x = 0, 4, or 8 were investigated by dynamic light scattering (DLS) and transmittance measurements (turbidimetry). The polymers reveal a complex aggregation behavior with up to three relaxation modes in the DLS data and with a transmittance that first goes through a minimum before it declines at high temperatures. At low temperatures, unassociated polymer chains were found to co-exist with larger aggregates. As the temperature is increased, enhanced association and contraction of the aggregates results in a drop of the transmittance values. The aggregates fragment into smaller micellar-like clusters when the temperature is raised further, causing the samples to become optically clear again. At high temperatures, the polymers aggregate into large compact clusters, and the samples become turbid. Interestingly, very large aggregates were observed at low temperatures when the polymer concentrations were low. The formation of these aggregates was also promoted by a more hydrophilic copolymer structure. The formation of large aggregates with an open structure at conditions where the solvent conditions are improved is probably caused by depletion flocculation of the smaller aggregates.

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