Dissipation dynamics of field-free molecular alignment for symmetric-top molecules: Ethane (C2H6)

2018 ◽  
Vol 148 (12) ◽  
pp. 124303 ◽  
Author(s):  
H. Zhang ◽  
F. Billard ◽  
X. Yu ◽  
O. Faucher ◽  
B. Lavorel
Keyword(s):  
Molecular Alignment ◽  
Symmetric Top Molecules

Observing the relaxation of molecular orientation in sheared liquid crystalline polymer solutions

1990 ◽  
Vol 48 (4) ◽  
pp. 1092-1093
Author(s):  
Wendy Putnam ◽  
Christopher Viney
Keyword(s):  
Molecular Orientation ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Polymer Processing ◽  
Molecular Alignment ◽  
Global Alignment ◽  
Shear Direction ◽  
Axial Strength ◽  
Strength And Stiffness

Liquid crystalline polymers (solutions or melts) can be spun into fibers and films that have a higher axial strength and stiffness than conventionally processed polymers. These superior properties are due to the spontaneous molecular extension and alignment that is characteristic of liquid crystalline phases. Much of the effort in processing conventional polymers goes into extending and aligning the chains, while, in liquid crystalline polymer processing, the primary microstructural rearrangement involves converting local molecular alignment into global molecular alignment. Unfortunately, the global alignment introduced by processing relaxes quickly upon cessation of shear, and the molecular orientation develops a periodic misalignment relative to the shear direction. The axial strength and stiffness are reduced by this relaxation.Clearly there is a need to solidify the liquid crystalline state (i.e. remove heat or solvent) before significant relaxation occurs. Several researchers have observed this relaxation, mainly in solutions of hydroxypropyl cellulose (HPC) because they are lyotropic under ambient conditions.

Molecular Alignment of Homoleptic Iridium Phosphors in Organic Light‐Emitting Diodes

2021 ◽  
pp. 2102882
Author(s):  
Moon Chul Jung ◽  
John Facendola ◽  
Jongchan Kim ◽  
Daniel Sylvinson Muthiah Ravinson ◽  
Peter I. Djurovich ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Molecular Alignment ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light

Photodeformable Azobenzene-Containing Polyimide with Flexible Linkers and Molecular Alignment

2021 ◽  
pp. 469-475
Author(s):  
Panpan Zhang ◽  
Zhongxu Lan ◽  
Jia Wei ◽  
Yanlei Yu
Keyword(s):  
Molecular Alignment

scholarly journals Molecular alignment echoes probing collision-induced rotational-speed changes

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
J.-M. Hartmann ◽  
J. Ma ◽  
T. Delahaye ◽  
F. Billard ◽  
E. Hertz ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Molecular Alignment

Strong molecular alignment in anisotropic fluid media

1996 ◽  
Vol 260 (3-4) ◽  
pp. 441-446 ◽  
Author(s):  
A.J. Bain ◽  
P. Chandna ◽  
G. Butcher
Keyword(s):  
Molecular Alignment ◽  
Anisotropic Fluid ◽  
Fluid Media

Temperature Gradients Through EHD Films and Molecular Alignment Evidenced By Infrared Spectroscopy

1981 ◽  
Vol 103 (1) ◽  
pp. 65-73 ◽  
Author(s):  
V. W. King ◽  
J. L. Lauer
Keyword(s):  
Absorption Spectrum ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Molecular Alignment ◽  
Temperature Gradients ◽  
Spectral Change ◽  
Continuum Source ◽  
Polyphenyl Ether ◽  
Elementary Analysis ◽  
Gap Width

Partial and complete emission band reversals have been observed in the infrared emission spectra from portions of operating sliding contacts. An elementary analysis has been carried out to show that partial reversals are due to temperature gradients in the fluid film—the film acts both as a radiation-emitter and absorber, and that total reversals—an emission spectrum appears as an absorption spectrum—are likely to be due to a continuum source, such as hot solid asperities. The total energy radiated under the latter conditions exceeds that under the others. A decrease in gap width with increased load was accompanied by a dramatic spectral change in the case of 5P4E polyphenyl ether, which is indicative of molecular alignment.

HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: XIII. ROTATIONAL SPECTRA AND STRUCTURES OF THE ZINC-, CADMIUM-, AND MERCURY-DIMETHYL MOLECULES

1960 ◽  
Vol 38 (11) ◽  
pp. 1516-1525 ◽  
Author(s):  
K. Suryanarayana Rao ◽  
B. P. Stoicheff ◽  
R. Turner
Keyword(s):  
Raman Spectroscopy ◽  
High Resolution ◽  
Rotational Constants ◽  
Carbon Bond ◽  
Rotational Spectra ◽  
Bond Lengths ◽  
Zinc Cadmium ◽  
Symmetric Top Molecules

The pure rotational spectra of gaseous Zn(CH3)2, Cd(CH3)2, Hg(CH3)2, and of the fully deuterated molecules have been photographed with a 21-ft grating. The spectra are typical of symmetric top molecules and consist of many evenly spaced rotational lines having a separation of about 0.45 cm−1. An analysis of the spectra yielded the rotational constants (in cm−1)[Formula: see text]From these constants the following metal—carbon bond lengths were determined: Zn—C = 1.929 Å, Cd—C = 2.112 Å, and Hg—C = 2.094 Å. Relations for the C—H bond lengths and HCH angles were also obtained.

Sign in / Sign up

Export Citation Format

Share Document