Photo-orientation Processes in Liquid Crystalline Polymethacrylates with Side Azobenzene Groups Having Lateral Methyl Substituents

2021 ◽  
Author(s):  
Artem Boychuk ◽  
Valery Shibaev ◽  
Martin Cigl ◽  
Karel Pomeisl ◽  
Vĕra Hamplová ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Azobenzene Groups

2000 Macromolecular Science and Engineering Award LectureThe versatility of azobenzene polymers

2001 ◽  
Vol 79 (7) ◽  
pp. 1093-1100 ◽  
Author(s):  
Almeria Natansohn ◽  
Paul Rochon
Keyword(s):  
Liquid Crystalline ◽  
Surface Deformation ◽  
Polymer Structure ◽  
Light Polarization ◽  
Polymer Materials ◽  
Science And Engineering ◽  
Crystalline Polymers ◽  
The Third ◽  
Macroscopic Motion ◽  
Azobenzene Groups

The well-known trans–cis–trans photoisomerization of azobenzenes produces at least three different kinds of motion in the polymer materials to which the azobenzenes are bound. The first is a photoinduced motion of the azobenzene groups only, and they can align in a selected position with respect to the light polarization. The second is a macroscopic motion of huge amounts of polymeric material, producing surface deformation, and the third is a reorganization of smectic domains in liquid crystalline polymers. These motions and their consequences are briefly discussed in relation to the polymer structure and some possible photonic applications are mentioned.Key words: photoinduced orientation, azobenzene polymers, surface gratings, photonics, thermochromism, photochromism, photorefractivity, photoinduced chirality and switching.

scholarly journals Synthesis and mesomorphic properties of nonsymmetric liquid crystalline dimers containing azobenzene groups

2009 ◽  
Vol 82 (3) ◽  
pp. 228-239 ◽  
Author(s):  
Md Lutfor Rahman ◽  
Jahimin Asik ◽  
Sandeep Kumar ◽  
Sidik Silong ◽  
Mohd Zaki Ab Rahman
Keyword(s):  
Liquid Crystalline ◽  
Mesomorphic Properties ◽  
Azobenzene Groups

Synthesis and Characterization of a Novel Liquid Crystalline Polymer Bearing Azobenzene

2011 ◽  
Vol 181-182 ◽  
pp. 47-50
Author(s):  
Xin De Tang ◽  
Ye Chen ◽  
Xin Wang ◽  
Fa Qi Yu ◽  
Mei Shan Pei
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Gel Permeation Chromatography ◽  
Crystalline Polymer ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
Polymer Bearing ◽  
Mesomorphic Properties ◽  
Azobenzene Groups

A novel liquid crystalline polymer bearing azobenzene groups in both main chain and side chain has been successfully synthesized by atom transfer radical polymerization (ATRP). Dual bromide-terminated azobenzene was used as the initiator for the ATRP of azobenzene-containing monomer (M6C). The structure of the resulting polymer was confirmed by nuclear magnetic resonance (NMR), and the molecular weight and its dispersity was characterized by gel permeation chromatography (GPC). The mesomorphic properties of this novel polymer were characterized by means of polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The results demonstrated that this polymer can form mesophases.

Combined Main-Chain/Side-Chain Liquid Crystalline Polymer with Main-Chain On the basis of “Jacketing” Effect and Side-Chain Containing Azobenzene Groups

2011 ◽  
Vol 44 (19) ◽  
pp. 7600-7609 ◽  
Author(s):  
He-Lou Xie ◽  
Shao-Jie Wang ◽  
Guan-Qun Zhong ◽  
Yi-Xin Liu ◽  
Hai-Liang Zhang ◽  
...  
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Main Chain ◽  
Crystalline Polymer ◽  
Side Chain ◽  
Azobenzene Groups

scholarly journals Dynamic mechanical and thermal behavior of novel liquid-crystalline polybutadiene-diols with azobenzene groups in side chains

2013 ◽  
Vol 57 (5) ◽  
pp. 1297-1310 ◽  
Author(s):  
Lenka Poláková ◽  
Zdeňka Sedláková ◽  
Hynek Beneš ◽  
Helena Valentová ◽  
Ivan Krakovský ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Liquid Crystalline ◽  
Side Chains ◽  
Dynamic Mechanical ◽  
Azobenzene Groups

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

Structure-property relations of liquid crystalline polymers

1987 ◽  
Vol 45 ◽  
pp. 460-463
Author(s):  
Linda C. Sawyer
Keyword(s):  
Solid State ◽  
Liquid Crystalline ◽  
Structural Model ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Mechanical Anisotropy ◽  
Structure Property ◽  
Preparation Methods ◽  
Crystalline Polymers ◽  
Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

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