Differential scanning calorimetric and Raman studies of a phase transition in[C3H7NH3]2SiF6

2004 ◽  
Vol 35 (4) ◽  
pp. 261-265 ◽  
Author(s):  
H. Jeghnou ◽  
A. Ouasri ◽  
M. Elyoubi ◽  
A. Rhandour ◽  
M.-C. Dhamelincourt ◽  
...  
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetric

Differential scanning calorimetric studies on phase transition of glucose and cellulose oligosaccharides

Polymer ◽  
1976 ◽  
Vol 17 (7) ◽  
pp. 559-562 ◽  
Author(s):  
T HATAKEYAMA ◽  
H YOSHIDA ◽  
C NAGASAKI ◽  
H HATAKEYAMA
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Studies

Differential scanning calorimetric studies of the phase transition in adamantanone

1986 ◽  
Vol 82 (4) ◽  
pp. 535 ◽  
Author(s):  
Ian S. Butler ◽  
Holly B. R. Cole ◽  
D. F. R. Gilson ◽  
Pierre D. Harvey ◽  
Joanna D. McFarlane
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Studies

On the Thermal Behaviour of Some Alkali Branched Alkanoates. Note I

1978 ◽  
Vol 33 (2) ◽  
pp. 240-242 ◽  
Author(s):  
P. Ferloni ◽  
M. Sanesi ◽  
P. L. Tonelli ◽  
P. Franzosini
Keyword(s):  
Phase Transition ◽  
Thermal Behaviour ◽  
Differential Scanning Calorimetric ◽  
Transition Temperatures ◽  
Calorimetric Investigation ◽  
Temperature Range ◽  
Heat Effects ◽  
Phase Transition Temperatures ◽  
Sodium And Potassium

Lithium, sodium and potassium isobutyrates, isovalerates and isocaproates were submitted to a differential scanning calorimetric investigation in the temperature range between 320 K and the isotropic melt region. The collected phase transition temperatures and heat effects are compared to those of the corresponding linear isomers. In particular the occurrence of mesomorphic liquids and the width of their existence fields is discussed.

scholarly journals A Molecular Shape Recognitive HPLC Stationary Phase Based on a Highly Ordered Amphiphilic Glutamide Molecular Gel

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1574
Author(s):  
Naoki Kawamoto ◽  
Yongxing Hu ◽  
Yutaka Kuwahara ◽  
Hirotaka Ihara ◽  
Makoto Takafuji
Keyword(s):  
Phase Transition ◽  
Stationary Phase ◽  
Separation Efficiency ◽  
Molecular Shape ◽  
Differential Scanning Calorimetric ◽  
Side Chains ◽  
Calorimetric Analysis ◽  
Polymer Backbone ◽  
Phenol Derivatives ◽  
Flexible Polymer

Chiral glutamide-derived lipids form self-assembled fibrous molecular gels that can be used as HPLC organic phases. In this study, HPLC separation efficiency was improved through the addition of branched amphiphilic glutamide lipids to the side chains of a terminally immobilized flexible polymer backbone. Poly(4-vinylpyridine) with a trimethoxysilyl group at one end was grafted onto the surface of porous silica particles (Sil−VP15, polymerization degree = 15), and the pyridyl side chains were quaternized with a glutamide lipid having a bromide group (BrG). Elemental analysis indicated that the total amount of the organic phase of the prepared stationary phase (Sil−VPG15) was 38.0 wt%, and the quaternization degree of the pyridyl groups was determined to be 32.5%. Differential scanning calorimetric analysis of a methanol suspension of Sil−VPG15 indicated that the G moieties formed a highly ordered structure below the phase transition temperature even on the silica surface, and the ordered G moieties exhibited a gel-to-liquid crystalline phase transition. Compared with a commercially available octadecylated silica column, the Sil−VPG15 stationary phase showed high selectivity toward polycyclic aromatic hydrocarbons, and particularly excellent separations were obtained for geometrical and positional isomers. Sil−VPG15 also showed highly selective separation for phenol derivatives, and bio-related molecules containing phenolic groups such as steroids were successfully separated. These separation abilities are probably due to multiple interactions between the elutes and the highly ordered functional groups, such as the pyridinium and amide groups, on the highly ordered molecular gel having self-assembling G moieties.

scholarly journals THERMAL AND ELECTRICAL BEHAVIOUR OF THE SUPERPROTONIC CONDUCTOR PHASE IN Rb2(HSeO4)1.5(H2AsO4)0.5

2014 ◽  
Vol 10 (7) ◽  
pp. 2967-2977
Author(s):  
Noura NOUIRI ◽  
Khaled JAOUADI ◽  
Tahar MHIRI
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Complex Modulus ◽  
Differential Scanning Calorimetric ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Impedance Measurements ◽  
X Ray ◽  
Superprotonic Phase Transition ◽  
Superprotonic Phase

Crystals of a new compound with a superprotonic phase transition Rb2(HSeO4)1.5(H2AsO4)0.5 (noted RbHSeAs), were synthesized by slow evaporation of an aqueous solution at room temperature. The differential scanning calorimetric analyses showed two endothermic peaks at 465 K and 566 K. The last peak corresponds to the decomposition of the material. The first transition was characterized by several techniques (impedance spectroscopy, complex modulus, Raman and X-ray diffraction powder depending on temperature). ac impedance measurements revealed that, upon heating, the compound undergoes at ~ 443 K a sharp increase in conductivity from a low temperature protonic phase to a superprotonic conductivity phase. The activation energies calculated from the modulus (Ef) and impedance (E) spectra respectively are approximately equal, suggesting that the transport properties in this material above and below the superprotonic phase transition (443 K) are probably due to an H+ protons hopping mechanism.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

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