The peculiarities of the photoorientation processes in azobenzene-containing liquid crystalline homo- and co-dendrimers

Bobrovsky, Alexey; Boiko, N. I.; Shibaev, Valéry

doi:10.1016/j.polymer.2014.11.046

Cited by 12 publications

(10 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The initial works on the photosensitive polymers were basically limited to a detailed study of LC azobenzene-containing homopolymers and random copolymers. [1][2][3][4][5][6][7][8][9][10] However, further development of these works received a bright continuation in the creation of more complex hybrid systems based on LC dendrimers [11][12][13] and LC block copolymers (PLCBCs) [14][15][16][17] of different architecture in which photochromic groups can be covalently attached to the backbone of polymers or as small guest molecules by noncovalent interactions (hydrogen bonds, ionic bonds, and so on). As a rule, block copolymers successfully combine the properties of their constituent subblocks, which allows creating new functional materials combining photochromism and optical properties of liquid crystals.…”

Section: Doi: 101002/marc202000384mentioning

confidence: 99%

Photopatterning of Azobenzene‐Containing Liquid Crystalline Triblock Copolymers: Light‐Induced Anisotropy and Photostabilization

Audia

Bugakov

Boiko

et al. 2020

Macromol. Rapid Commun.

View full text Add to dashboard Cite

Photochromic liquid crystalline block copolymers (PLCBCs) are currently playing a significant role as light‐responsive materials because of their light controllable features over multiple length scales. Herein, a study of the photoinduced optical anisotropy derived by the combination of orientation phenomena at molecular and supramolecular levels in a novel kind of side‐chain PLCBCs with mesogenic phenyl benzoate groups and pyridine units that is hydrogen bonded with azobenzene‐containing phenol is reported. Based on the polymeric architectures and composition, the supramolecular configuration self‐organizes in different microphases that affect the material response to the external stimuli. Simple, 1D, polarization holograms are recorded to evaluate the photoinduced birefringence. The first step, light patterning, involves the orientation of the azobenzene units and precedes a thermal treatment that amplifies the induced anisotropy through the cooperative orientation of the mesogenic units. By selective extraction, the azobenzene units can be removed, making the material transparent to the visible light. Excellent photostability of the material birefringence is obtained, whose final value is strongly affected by the block copolymer's architecture. The versatility in the molecular design, the fine control of the photoinduced features by external parameters, and, finally, the possibility to achieve photostability make these materials of great potential for developing optical and photonic devices.

show abstract

Section: Doi: 101002/marc202000384mentioning

confidence: 99%

Photopatterning of Azobenzene‐Containing Liquid Crystalline Triblock Copolymers: Light‐Induced Anisotropy and Photostabilization

Audia

Bugakov

Boiko

et al. 2020

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

“…[5][6][7][8][9][10][11][12] From the other hand, an action of polarized light induces photo-orientation processes and alignment of chromophores in direction perpendicular to the polarization plane of the incident light. [13][14][15][16][17][18][19][20] Another interesting direction of the research is connected with investigation of the surface topography of LC polymer systems and, especially, manipulation of surface relief by light irradiation. In a number of previous works, the ability of light control of surface topography has been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Photo-Orientation Phenomena in Photochromic Liquid Crystalline Azobenzene-Containing Polymethacrylates with Different Spacer Length

Bobrovsky

Shibaev

Piryazev

et al. 2017

Macromol. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Synthesis and investigation of the phase behavior and photo‐optical properties of two chiral liquid‐crystalline polymers with azobenzene‐containing side groups having different spacer lengths, 6 and 10 methylene groups (PMAzo‐6 and PMAzo‐10, respectively) are described. Formation of different smectic phases and high‐temperature cholesteric phase is studied by polarizing optical microscope, differential scanning calorimetry, and X‐ray investigations. It is shown that UV‐irradiation induces effective reversible E–Z photoisomerization in polymer solutions and films. Atomic force microscopy (AFM) study reveals substantial changes in the surface topography of the polymer PMAzo‐6 film after UV‐irradiation, whereas PMAzo‐10 surface remains the same. Irradiation by polarized light (457 nm) results in photo‐orientation process in polymer films consequential in significant alignment of the chromophores in direction perpendicular to the polarization plane of the incident light. A significant difference is found in thermal stability of the photoinduced alignment; an annealing of PMAzo‐10 irradiated samples results in a slight decrease of dichroism values (down to 0.57); whereas the dichroism increases up to very high values (0.91) for PMAzo‐6.

show abstract

“…Action of the polarized light on amorphous or LC films of azobenzene side chain polymers induces photo‐orientation process, that is, alignment of the azobenzene chromophores in direction perpendicular to the polarization plane of the excitation light . The mechanism of this process relates to the repetitive cycles of the E‐Z‐E isomerization of the chromophores followed by their rotational diffusion.…”

Section: Introductionmentioning

confidence: 99%

“…1,3,4 Action of the polarized light on amorphous or LC films of azobenzene side chain polymers induces photo-orientation process, that is, alignment of the azobenzene chromophores in direction perpendicular to the polarization plane of the excitation light. [5][6][7][8][9][10][11][12] The mechanism of this process relates to the repetitive cycles of the E-Z-E isomerization of the chromophores followed by their rotational diffusion. This effect leads to an appearance of linear dichroism and birefringence in amorphous polymer films or realignment of the chromophores in LC films that could be used for the creation of materials for optical data recording and other useful applications in photonics 13 and organic photovoltaics.…”

mentioning

confidence: 99%

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Bobrovsky

Shibaev

Cigl

et al. 2016

J. Polym. Sci. Part A: Polym. Chem.

Self Cite

View full text Add to dashboard Cite

Two photosensitive chiral liquid crystalline azobenzene‐containing polymethacrylates having different length of flexible spacer connecting chromophores with backbone were synthesized and their phase behavior and photo‐optical properties were studied. Both polymers consist of lateral methyl substituents in ortho‐position of azobenzene chromophores providing high photosensitivity even in red spectral region as well as high thermal stability of photoinduced Z‐form of azobenzene chromophores. It is shown, that smectic phase (SmA*) formation in films of polymer with longer spacer predetermines its quite unusual spectral response to UV and subsequent visible light actions. The SmA* phase promotes spontaneous homeotropic alignment of azobenzene chromophores in polymer films. UV‐irradiation induces not only E‐Z isomerization but also results in disruption of homeotropic alignment, whereas subsequent visible light action enables to obtain films with the low degree of chromophores orientation. The photo‐orientation phenomena under the action of polarized light of different wavelength on polymer films were studied. The possibility of using red polarized light of moderate intensity for optical photorecording on polymer films is demonstrated. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2962–2970

show abstract

The peculiarities of the photoorientation processes in azobenzene-containing liquid crystalline homo- and co-dendrimers

Cited by 12 publications

References 47 publications

Photopatterning of Azobenzene‐Containing Liquid Crystalline Triblock Copolymers: Light‐Induced Anisotropy and Photostabilization

Photopatterning of Azobenzene‐Containing Liquid Crystalline Triblock Copolymers: Light‐Induced Anisotropy and Photostabilization

Photo-Orientation Phenomena in Photochromic Liquid Crystalline Azobenzene-Containing Polymethacrylates with Different Spacer Length

Azobenzene‐containing LC polymethacrylates highly photosensitive in broad spectral range

Contact Info

Product

Resources

About