scholarly journals Cholesteric Liquid Crystalline Materials with a Dual Circularly Polarized Light Reflection Band Fixed at Room Temperature

2011 ◽  
Vol 115 (20) ◽  
pp. 6421-6426 ◽  
Author(s):  
Gonzague Agez ◽  
Michel Mitov
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Polarized Light ◽  
Light Reflection ◽  
Reflection Band ◽  
Circularly Polarized Light ◽  
Crystalline Materials ◽  
Circularly Polarized ◽  
Liquid Crystalline Materials ◽  
Cholesteric Liquid Crystalline

scholarly journals Strategies to Stabilize the Photoinduced Supramolecular Chirality in Azobenzene Liquid Crystalline Polymers

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 885 ◽  
Author(s):  
Jorge Royes ◽  
Luis Oriol ◽  
Rosa M. Tejedor ◽  
Milagros Piñol
Keyword(s):  
Block Copolymers ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Temporal Stability ◽  
Polarized Light ◽  
Thermal Characterization ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Crystalline Polymers ◽  
Supramolecular Chirality

This paper describes the synthesis, thermal characterization and optical properties of liquid crystalline homopolymers and block copolymers with a repeating unit consisting of two functional units, with at least one of them being an azobenzene. Films of these polymers have been irradiated with circularly polarized light at room temperature, evaluating the intensity of the photoinduced chiral signal and its temporal stability upon storage. The paper also explores two different strategies to restrict the relaxation of the photoinduced order. Firstly, block copolymers have been prepared to confine the photoaddressable segments into nanoscopic domains where relaxation should be restricted. Secondly, an alternative homopolymer has been synthesized where the repeating unit combines two chromophores that can be separately photoaddressed, an azobenzene unit to efficiently photoinduce chirality and a cinnamate to fix the chiral signal by photocrosslinking.

On resolving fine periodic microstructures in the optical microscope

1989 ◽  
Vol 47 ◽  
pp. 364-365
Author(s):  
W.S. Putnam ◽  
C. Viney
Keyword(s):  
Liquid Crystalline ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Normal Incidence ◽  
Optical Microscope ◽  
Angle Of Incidence ◽  
Resolution Limit ◽  
Crystalline Materials ◽  
Periodic Microstructures ◽  
Liquid Crystalline Materials

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.

scholarly journals Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene)hydrazines

2019 ◽  
Vol 43 (1-2) ◽  
pp. 67-77 ◽  
Author(s):  
Adil A Awad ◽  
Al-Ameen Bariz OmarAli ◽  
Ahmed Jasim M Al-Karawi ◽  
Zyad Hussein J Al-Qaisi ◽  
Samer Ghanim Majeed
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Luminescent Properties ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
X Ray ◽  
Step Procedure ◽  
Liquid Crystalline Materials

{1-[4-( n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines ( n-alkoxy = O(CH2) nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.

Room-Temperature Columnar Liquid Crystalline Materials Based on Pyrazino[2,3-g]quinoxaline for Bright Green Organic Light-Emitting Diodes

2019 ◽  
Vol 1 (9) ◽  
pp. 1959-1969 ◽  
Author(s):  
Vinod Kumar Vishwakarma ◽  
Subrata Nath ◽  
Monika Gupta ◽  
Deepak Kumar Dubey ◽  
Sujith Sudheendran Swayamprabha ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Crystalline Materials ◽  
Organic Light ◽  
Bright Green ◽  
Liquid Crystalline Materials
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