Effect of Molecular Structure and Thermal Treatment on Photo‐optical Properties of Photochromic Azobenzene‐containing Polymer Films

Abstract

Three novel photochromic azobenzene‐containing comb‐shaped polyacrylates are synthesized and their phase behavior and photo‐optical properties are studied. The influence of the side photochromic group structure, thermal treatment, and light irradiation on aggregation of azobenzene chromophores in thin spin‐coated films of the polymers is investigated in detail. Special attention is paid to studying the photo‐orientation processes in polymers films induced by polarized blue light (473 nm). The relationship between the photochromic group architecture, phase behavior, thermal treatment of films, and kinetics of chromophore photo‐orientation is established and discussed. It is found that the position of the NN bond in chromophores plays an important role in the kinetics of the process, but does not affect the maximum value of dichroism. magnified image

Effect of alkyl chains length on properties of ferroelectric liquid crystals with the keto group attached to the molecule core

“…are often reasonable, in the range 30-70 C, and the LC phases can easily be supercooled well below room temperature and (iv) lactic acid-based LCs usually show no ageing, and are highly stable, thermally as well as chemically. Moreover, introduction of double bond or -OH polymerizable groups [9,[30][31][32] or adding the photosensitive azo group [15][16]20,32] in the molecular core can strongly increase the potential functionality of this class of chiral LC materials and can make them useful for photonics, telecommunications, non-linear optics, etc.…”

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

“…Mesomorphic properties of TL5 with two hydroxy groups can be compared to those of the chiral compounds with terminal acrylic group in the nonchiral chain prepared as monomers for side-chain polyacrylates [33–34]. All these compounds clearly possess the LC behaviour and exhibit the chiral nematic phase and also the chiral smectic phases.…”

“…No pronounced difference in clearing point has been found in cases where the molecule core is the same as for TL5 but the nonchiral chain with a double bond is replaced by that with two hydroxy groups. However, a minor increase in the melting point (about 10 K) has been observed for TL5 with respect to that of the chiral acrylates [34]. …”

Preparation and characterization of novel side-chain azobenzene polymers containing tetrazole group

“…In recent years, polymeric materials containing azobenzene chromophore have drawn widespread attention due to their unique optical trans-cis-trans isomerization [1][2][3][4], which can be potentially applied in many fields, such as optical data storage [5,6], liquid crystal display [7][8][9], photoinduced birefringence [10], and holographic surface relief grating [11,12]. As well known, the photoresponsive behavior of azobenzene polymers is based on reversible transcis-trans photoisomerization of the azobenzene chromophore and possibly large-scale mass movement of the rigid azobenzene chromophore [11][12][13][14][15].…”