Ordering phenomena and photoorientation processes in photochromic thin films of LC chiral azobenzene-containing polymer systems

Bobrovsky, Alexey; Ryabchun, Alexander; Медведев, А. В.; Shibaev, Valéry

doi:10.1016/j.jphotochem.2009.05.010

Cited by 25 publications

(35 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The particles are made of liquid crystal copolymer PAAzo bearing mesogenic and azobenzene photoactive groups (Figure a). By combining the photochromism of azobenzene and self‐organization of the liquid crystalline phase, we target the enhancement of photo‐optical and optomechanical feedbacks of the material. We have fabricated the soft elastic composites contacting active microparticles in two steps, mixing and casting/coating.…”

Section: Introductionmentioning

confidence: 99%

Photocontrollable Deformations of Polymer Particles in Elastic Matrix

Ryabchun

Bobrovsky

2019

Advanced Optical Materials

Self Cite

View full text Add to dashboard Cite

into mechanical motion or work, such as photoactuation. [1][2][3][4][5] The funda mental importance of these phenomena occurring under the action of light, such as photofluidization, [6][7][8][9][10][11] photoimmo bilization, [6,12,13] formation of surface relief gratings, [14][15][16][17] and other complex 3D structures [10,[18][19][20][21][22][23][24] can help to develop photo responsive materials for versatile applications and will also improve and extend our knowledge in soft matter.The most extensively studied photo active materials usually contain azoben zene moieties as the lightresponsive unit. The properties of azobenzene such as high quantum yield and reversibility of E-Z photoisomerization, high fatigue resis tance, and large changes in molecular shape and dipole moment upon isomerization make it uniquely suitable as an active unit. Molecular shape changes of azobenzene can be harnessed on a macroscopic level by the embedding active molecules into hierarchically organized matter [25] and by confinement of the photoactive material in space, such as, spherical colloids which can selfassemble into 2D and 3D structures (photonic crys tals). The preparation and study of spherical micrometersized particles based on azobenzene polymers have been reported in a number of recent works revealing the importance for various optical microdevices, photonics, microfluidics, etc. [26][27][28][29][30][31][32][33][34][35][36][37][38] It has been demonstrated that polarized light irradiation results in elongation of these particles along the light polarization. Despite the interest to the research area, several issues like the mechanism and reversibility of microscopic shape changes are still elusive. Moreover, there are no reports on the influence of liquid crystal line (LC) ordering on the shapeshifting and optical properties of the particles, as well as the operation of microparticles has never been exploited to build materials with macroscopic functionalities.In the current work, we have developed a novel elastic composite material containing shapereconfigurable parti cles based on liquid crystalline polymer. We have used sty rene-ethylene-butylene-styrene triblock copolymer (SEBS, Figure 1a) as the elastic matrix which provides large deforma tion and low mechanical stiffness [39] and does not interfere to the deformation of embedded particles. Another important role of the matrix is its elasticity responsible for the compres sive forces experienced by the deformed particles which makes possible the shape to recover. The particles are made of liquid crystal copolymer PAAzo bearing mesogenic and azobenzene One of the key challenges of material science currently is the design of multifunctional "smart" materials combining features from both molecular and supramolecular levels. Pursuing the strategy of amplification and transduction of light-induced motion of small molecules (photoswitches) across increasing length scales to macroscopic level, a novel polymer composite based on shapereconfigurable microparticles is desig...

show abstract

Section: Introductionmentioning

confidence: 99%

Photocontrollable Deformations of Polymer Particles in Elastic Matrix

Ryabchun

Bobrovsky

2019

Advanced Optical Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…As was shown before, the copolymer containing only azobenzene and phenylbenzoate groups (1:1) obtained by copolymerization of monomers M4 and M5 is characterized by a nematic phase with clearing temperature of about 120 °C 24. Introduction of crown ether groups as side chains causes a decrease in clearing temperatures due to their low anisometry.…”

Section: Resultsmentioning

confidence: 53%

Crown‐ether and azobenzene‐containing liquid crystalline polymers: An influence of macromolecular architecture on optical properties and photo‐orientation processes

Ryabchun

Bobrovsky

Медведев

et al. 2010

J. Polym. Sci. A Polym. Chem.

Self Cite

View full text Add to dashboard Cite

A series of novel crown ether‐containing photochromic comb‐shaped liquid crystalline polyacrylates with different macromolecular structure of side groups were synthesized and investigated. Phase behavior, optical and photo‐optical properties of thin spin‐coated films of these polymers were studied. A special attention was paid to a comparative study of the photo‐orientation phenomena occurring in the polymer films under a polarized light action. It was shown that complex formation with the potassium ions results in the decrease in degree of the photoinduced order that can be used for the creation of new materials for sensor devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

show abstract

“…1(a). The synthesis of the polymer is described elsewhere [39]. Transition temperatures for the polymer are T g = 24 • C (glassy to nematic), T NI = 120 • C (nematic to isotropic).…”

Section: Methodsmentioning

confidence: 99%

“…It is known [39,40] that thin films of the polymer studied exhibit photo-orientation upon irradiation with linearly polarized visible light [ Fig. 1(b)].…”

Section: Methodsmentioning

confidence: 99%

Laser-induced holographic light scattering in a liquid-crystalline azobenzene-containing polymer

et al. 2012

Self Cite

View full text Add to dashboard Cite

The holographic scattering phenomenon was observed and studied in detail for azobenzene-containing polymer system. It was found that irradiation of 25-μm-thick samples of the polymer with a single linearly polarized laser beam results in the appearance of a band with the maximum in the vicinity of irradiating wavelength in polarized extinction spectra. The band is completely polarized along the polarization direction of irradiating light. The shape of the band is exceedingly sensitive to rotation of the sample with respect to the spectrometer probe beam. An analogous band appears upon the irradiation of the sample with circularly polarized light. The observed phenomenon is presumably similar to holographic scattering, reported previously in photorefractive crystals and some photopolymers. A detailed description of the observed spectral changes is presented. The sensitivity of the effect towards probe light polarization and direction, irradiating light wavelength, and temperature is discussed.

show abstract

Ordering phenomena and photoorientation processes in photochromic thin films of LC chiral azobenzene-containing polymer systems

Cited by 25 publications

References 45 publications

Photocontrollable Deformations of Polymer Particles in Elastic Matrix

Photocontrollable Deformations of Polymer Particles in Elastic Matrix

Crown‐ether and azobenzene‐containing liquid crystalline polymers: An influence of macromolecular architecture on optical properties and photo‐orientation processes

Laser-induced holographic light scattering in a liquid-crystalline azobenzene-containing polymer

Contact Info

Product

Resources

About