The influence of conformational defects on the development of structural phase transition in tetracosane C24H50

Abstract The kinetics of the first-order solid-state structural transition in monodisperse n-alkanes samples of even tetracosane C24H50 was studied by FTIR spectroscopy. The existence of many irregular conformers in solid phases of tetracosane, the concentration of which reaches a maximum when approaching the melting temperature, has been demonstrated. The existence of these defective molecules promotes transitions between different rotator phases in the solid state.

Download Full-text

Solid-state phase transition in n-alkanes of different parity

Journal of Physics Conference Series ◽

10.1088/1742-6596/2086/1/012182 ◽

2021 ◽

Vol 2086 (1) ◽

pp. 012182

Author(s):

S A Gureva ◽

A K Borisov ◽

V A Marikhin ◽

V M Egorov

Keyword(s):

Crystal Structure ◽

Phase Transition ◽

Solid State ◽

Ftir Spectroscopy ◽

Structural Transition ◽

Structural Phase ◽

First Order ◽

Structure Rearrangement ◽

Kinetics Of ◽

New Phase

Abstract The kinetics of the first-order solid-state structural transition in monodisperse n-alkanes samples of tricosane C23H48 and tetracosane C24H50 was studied by DSC and FTIR spectroscopy. The initial nuclei location of the new phase was revealed. The process of crystal structure rearrangement is initiated in the interlayers between neighboring lamellar for odd tricosane, while the nanonuclei in even tetracosane arise in the crystalline lamella cores. Thus, the influence of the number evenness of carbon atoms in the n-alkanes chains on the first-order structural phase transition has been proved.

Download Full-text

Temperature-triggered order–disorder phase transition in molecular-ionic material N-butyldiethanolammonium picrate monohydrate

RSC Advances ◽

10.1039/c6ra12178k ◽

2016 ◽

Vol 6 (73) ◽

pp. 69546-69550 ◽

Cited By ~ 5

Author(s):

Tariq Khan ◽

Muhammad Adnan Asghar ◽

Zhihua Sun ◽

Chengmin Ji ◽

Lina Li ◽

...

Keyword(s):

Phase Transition ◽

Structural Phase Transition ◽

Structural Phase ◽

Dielectric Materials ◽

Disorder Phase Transition ◽

First Order ◽

Oxygen Atoms

We report an organic–ionic material that undergoes a first-order structural phase transition, induced by order–disorder of oxygen atoms in picrate anion. This strategy offers a potential pathway to explore new switchable dielectric materials.

Download Full-text

Near-room-temperature reversible giant barocaloric effects in [(CH3)4N]Mn[N3]3 hybrid perovskite

Materials Advances ◽

10.1039/d0ma00652a ◽

2020 ◽

Vol 1 (9) ◽

pp. 3167-3170 ◽

Cited By ~ 2

Author(s):

Jorge Salgado-Beceiro ◽

Ariel Nonato ◽

Rosivaldo Xavier Silva ◽

Alberto García-Fernández ◽

Manuel Sánchez-Andújar ◽

...

Keyword(s):

Phase Transition ◽

Structural Phase Transition ◽

Room Temperature ◽

Structural Phase ◽

Inorganic Perovskite ◽

First Order ◽

Hybrid Perovskite

We report giant reversible barocaloric effects in [(CH3)4N]Mn[N3]3 hybrid organic–inorganic perovskite, near its first-order cubic-monoclinic structural phase transition at T0 ∼ 305 K.

Download Full-text

Phase Transitions and Water Dynamics of [Mn(H2O)6](ClO4 )2 Studied by Differential Scanning Calorimetry and Neutron Scattering Methods

Zeitschrift für Naturforschung A ◽

10.1515/zna-2000-9-1003 ◽

2000 ◽

Vol 55 (9-10) ◽

pp. 759-764 ◽

Cited By ~ 4

Author(s):

E. Mikuli ◽

A. Migdał-Mikuli ◽

I. Natkaniec ◽

J. Mayer

Keyword(s):

Phase Transition ◽

Low Temperature ◽

Neutron Scattering ◽

Structural Phase Transition ◽

Room Temperature ◽

Structural Phase ◽

Water Dynamics ◽

Water Molecules ◽

Temperature Phase ◽

Solid Phases

Abstract DSC measurements performed at 95 -290 K have shown that [Mn(H 2 O) 6 ](CIO 4) 2 possesses, besides a high-temperature phase, existing above 323 K, four low-temperature solid phases. The inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) pat-terns registered at 20 -290 K have supported the DSC results and provided evidence that the investigated substance possesses even more than five solid phases. The IINS spectra have shown that in the room-temperature phase, water molecules perform fast stochastic reorientation at the picosecond scale. The orientational disorder characteristic for the room-temperature phase can be easily overcooled and frozen. Even by relatively slow cooling at ca. 40 K/hour a metastable, orientational (protonic) glass phase is formed below ca. 160 K. Below ca. 100 K, a structural phase transition was observed by the NPD, however the IINS spectra indicate existence of the pure ordered low-temperature phase only after annealing the sample for a few hours at 100 K. On heating, a structural phase transition takes place at ca. 120 K, and at ca. 225 K water molecules begin fast reorientation.

Download Full-text