The effect of spacer and alkyl tail lengths on the photoorientation processes in amorphousized films of azobenzene-containing liquid crystalline polymethacrylates

ABSTRACT

In our days, photochromic polymers possessing the liquid crystalline behaviour attract considerable attention of the scientific community due to their functionality and highlighted effects which can be used for opto-electronics and photonics. Herein, the photoorientation processes under the action of the polarised UV (355 nm) and visible (457 nm) light are studied for the amorphousized films of new azobenzene-containing polymethacrylates with different lengths of alkyl spacers and tails (5, 6 and 10 methylene units). The prominent effects of the chemical structure, namely length of the alkyl spacers and tails, as well as wavelength of the excitation light, on the peculiarities of the photoorientation process are demonstrated. Those effects can lead to quite important conclusions concerning possible influence of the microphase separation in polymer films.

Graphical abstarct

KEYWORDS:

• Liquid crystalline polymers
• photoisomerization
• azobenzene
• photoorientation

Acknowledgments

This research was supported by: the Russian Science Foundation (19-13-00029; polymers synthesis and study of their phase behaviour; A. Bobrovsky, V. Shibaev); Russian Foundation for Basic Research (19-03-00337; study of the photoorientation processes; A. Bobrovsky, V. Shibaev); the Czech Science Foundation (CSF 19-03564S) and MEYS (LTC19051); synthesis of the monomers and their characterization; M. Cigl, V. Hamplová, A. Bubnov. Authors thank Dr. M. Bugakov for the GPC measurements. The study of the structure and phase behavior of LC polymethacrylates at FSRC “Crystallography and Photonics” RAS and Kurchatov Synchrotron Centre were supported by the Ministry of Science and Higher Education within the corresponding State assignments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Grantová Agentura České Republiky [CSF 19-03564S]; Ministry of Education, Youth and Sports of the Czech Republic [LTC19051]; Russian Science Foundation [19-13-00029]; Russian Foundation for Basic Research [19-03-00337].