Existence of Two Different Isotropic Phases as a Reason for Bistable Phase Behavior of an LC Side‐Chain Polymethacrylate

Polushin, S. G.; Rogozin, Viacheslav; Beloborodov, Ilya; Rjumtsev, E. I.; Kozlovsky, Mikhail V.

doi:10.1002/marc.200700638

Cited by 11 publications

(2 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The electro-optical properties of an isotropic melt above the nematic-isotropic melt phase transition temperature were studied by considering the Kerr effect, which serves as a tool for examining phase transitions in mesogens [9,10]. The electric field-induced birefringence ΔnE is related to the Kerr constant K and the electric field strength E by the Kerr equation: ΔnE = KE 2 .…”

Section: Methodsmentioning

confidence: 99%

Confinement Effect in a Thick Layer of LC Lanthanide Complex

Lezova

Polushina

Polushin

2018

The 1st International Electronic Conference on Crystals

Self Cite

View full text Add to dashboard Cite

The structure of metallomesogen complexes differs essentially from that of calamitic liquid crystals, which emerges in their physical properties. We studied anomalous features of the transition from the nematic to isotropic phase in the ytterbium-based liquid crystal complex. For this, two approaches were used. In the first approach, we showed that the experimental values of the dielectric and optical anisotropies measured near the phase transition turned out to be substantially smaller than their calculated values. This evidently occurs because the phase transition temperature in the deep region of the experimental cell differs from that near the surface of the cell. Secondly, the temperature of N–I transitions in metallomesogenic layers within glass sandwich cells is obtained directly by means of the polarization microscope method. It was found that the phase transition temperature drops in more than ten degrees when reducing the metallomesogenic layer thickness from 200 to 5 microns. The calamite liquid crystals show the confinement effect only within the interstice of the specific size smaller than one micron. An anomalous confinement effect can be caused by a strong interaction of the molecular complexes with each other.

show abstract

Section: Methodsmentioning

confidence: 99%

Confinement Effect in a Thick Layer of LC Lanthanide Complex

Lezova

Polushina

Polushin

2018

The 1st International Electronic Conference on Crystals

Self Cite

View full text Add to dashboard Cite

show abstract

“…Photoinduced dichroism, optical anisotropy and photorecording properties in these chiral Azo-polymers 6, 7 had been triggered by the anisotropic angular distribution of trans and cis isomers [ 159 , 160 , 161 , 162 ]. Furthermore, a chiral Azo-homopolymer 8 with an Azo chromophore bearing a chiral terminal chain was also reported by their group, which exhibited a photoinduced birefringence property and smectic A (SmA) or a twist grain boundary A* (TGBA*)-like bistable phase depending on the thermal history of the polymer (in particular, the cooling rate from the isotropic state) [ 163 , 164 , 165 ]. It was reported that this bistable phase behavior is related to two different isotropic states.…”

Section: Supramolecular Chirality Of Azo-polymers Constructed By Pmentioning

confidence: 99%

Supramolecular Chirality in Azobenzene-Containing Polymer System: Traditional Postpolymerization Self-Assembly Versus In Situ Supramolecular Self-Assembly Strategy

Cheng

Miao

Qian

et al. 2020

IJMS

View full text Add to dashboard Cite

Recently, the design of novel supramolecular chiral materials has received a great deal of attention due to rapid developments in the fields of supramolecular chemistry and molecular self-assembly. Supramolecular chirality has been widely introduced to polymers containing photoresponsive azobenzene groups. On the one hand, supramolecular chiral structures of azobenzene-containing polymers (Azo-polymers) can be produced by nonsymmetric arrangement of Azo units through noncovalent interactions. On the other hand, the reversibility of the photoisomerization also allows for the control of the supramolecular organization of the Azo moieties within polymer structures. The construction of supramolecular chirality in Azo-polymeric self-assembled system is highly important for further developments in this field from both academic and practical points of view. The postpolymerization self-assembly strategy is one of the traditional strategies for mainly constructing supramolecular chirality in Azo-polymers. The in situ supramolecular self-assembly mediated by polymerization-induced self-assembly (PISA) is a facile one-pot approach for the construction of well-defined supramolecular chirality during polymerization process. In this review, we focus on a discussion of supramolecular chirality of Azo-polymer systems constructed by traditional postpolymerization self-assembly and PISA-mediated in situ supramolecular self-assembly. Furthermore, we will also summarize the basic concepts, seminal studies, recent trends, and perspectives in the constructions and applications of supramolecular chirality based on Azo-polymers with the hope to advance the development of supramolecular chirality in chemistry.

show abstract