Azobenzene-Containing LC Polymethacrylates Highly Photosensitive in Broad Spectral Range Alexey Bobrovsky, 1 Valery Shibaev, 1 Martin Cigl, 2 V era Hamplov a, 2 Damian Pociecha, 3 Alexej Bubnov 2 1 Faculty of Chemistry, Moscow State University, Leninskie Gory, Moscow 119991, Russia 2 Chemistry department, Institute of Physics, The Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Prague 8, Czech Republic 3 Laboratory of Dielectrics and Magnetics, Chemistry Department, Warsaw University, Al. Zwirki I Wigury 101, Warsaw 02-089, Poland Correspondence to: A. Bobrovsky (E - mail: bbrvsky@yahoo.com) Received 15 March 2016; accepted 23 May 2016; published online 00 Month 2016 DOI: 10.1002/pola.28181 ABSTRACT: Two photosensitive chiral liquid crystalline azobenzene-containing polymethacrylates having different length of flexible spacer connecting chromophores with back- bone were synthesized and their phase behavior and photo- optical properties were studied. Both polymers consist of lat- eral methyl substituents in ortho-position of azobenzene chro- mophores 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 pre- determines its quite unusual spectral response to UV and sub- sequent visible light actions. The SmA* phase promotes spontaneous homeotropic alignment of azobenzene chromo- phores 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 polar- ized light of different wavelength on polymer films were stud- ied. The possibility of using red polarized light of moderate intensity for optical photorecording on polymer films is dem- onstrated. VC 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 00, 000–000 KEYWORDS: liquid-crystalline polymers (LCP); azo polymers; phase behavior; photochemistry; E-Z photoisomerization; photo-orientation INTRODUCTION Nowadays there are enormous world-wide efforts, in both industrial and academic laboratories, to develop new so-called “smart materials.” Azobenzene- containing low-molar-mass and polymer systems present tre- mendous interest for the development of new materials for optics, photonics and optoelectronics. 1 This interest is associ- ated with fascinating photochemical properties of the azo- benzene moieties, such as high quantum yield and reversibility of E-Z photoisomerization processes, high fatigue resistance in respect of the cycles E-Z-E isomeriza- tion, absence of the side photochemical processes, large changes in molecular anisometry, and dipole moment during E-Z isomerization, and so forth. 1,2 Among the different types of such compounds, liquid crystalline (LC) azobenzene- containing side and main chain polymers possess a number of unique properties and combine photosensitivity with the tendency to spontaneous self-organization, ability to form films, glassy coatings, and flexible fibers. 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. 5–12 The mechanism of this process relates to the repetitive cycles of the E-Z-E isomerization of the chro- mophores followed by their rotational diffusion. This effect leads to an appearance of linear dichroism and birefringence in amorphous polymer films or realignment of the chromo- phores in LC films that could be used for the creation of materials for optical data recording and other useful applica- tions in photonics 13 and organic photovoltaics. 14,15 Despite the large progress in the study of the photo- orientation phenomena in films of azobenzene side chain polymers there are still many open questions concerning influence of the molecular architecture of azobenzene chro- mophores, spacer length, and other structural fragments on peculiarities of the photoinduced alignment of Additional Supporting Information may be found in the online version of this article. VC 2016 Wiley Periodicals, Inc. WWW.MATERIALSVIEWS.COM JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 00, 000–000 1 JOURNAL OF POLYMER SCIENCE WWW.POLYMERCHEMISTRY.ORG ARTICLE