TY  - JOUR
A1  - Tomczyk, Jaroslaw
A1  - Sobolewska, Anna
A1  - Nagy, Zsuzsanna T.
A1  - Guillon, Daniel
A1  - Donnio, Bertrand
A1  - Stumpe, Joachim
T1  - Photo- and thermal-processing of azobenzene-containing star-shaped liquid crystals
JF  - Journal of materials chemistry : C, Materials for optical and electronic devices
N2  - A new class of star-shaped, liquid crystalline, low-molecular weight compounds functionalized with photochromic azobenzene and mesogenic groups was investigated in terms of light-induced anisotropy. The behaviour of the materials under the action of light with simultaneous or subsequent thermal treatment was examined with respect to the induction of anisotropy. The unconventional UV light treatment prior to the irradiation with linearly polarized light allowed induction of very high values of anisotropy (D = 0.77) at room temperature. Moreover, the simultaneous action of light and temperature led to the induction of higher values of dichroism in comparison with anisotropy generated by the standard procedure. Subsequent thermal treatment led to dewetting and the formation of 3D macroscopic stripe- and dome-like structures for one of the investigated compounds. Despite photoinduction of anisotropy by a single beam, the formation of polarization and surface relief gratings by two-beam interference pattern was also investigated.
Y1  - 2013
U6  - https://doi.org/10.1039/c2tc00627h
SN  - 2050-7526
VL  - 1
IS  - 5
SP  - 924
EP  - 932
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Schab-Balcerzak, Ewa
A1  - Flakus, Henryk
A1  - Jarczyk-Jedryka, Anna
A1  - Konieczkowska, Jolanta
A1  - Siwy, Mariola
A1  - Bijak, Katarzyna
A1  - Sobolewska, Anna
A1  - Stumpe, Joachim
T1  - Photochromic supramolecular azopolyimides based on hydrogen bonds
JF  - Optical materials : an international journal on the physics and chemistry of optical materials and their applications, including devices
N2  - The approach of deriving new photoresponsive active supramolecular azopolymers based on the hydrogen bonds is described. Polymers with imide rings, i.e., poly(esterimide)s and poly(etherimide)s, with phenolic hydroxyl or carboxylic groups were applied as matrixes for the polymer dye supramolecular systems. Supramolecular films were built on the basis of the hydrogen bonds between the functional groups of the polymers and various azochromophores, that is, 4-phenylazophenol, 4-[4-(6-hydroxyhexy loxy)phenylazo]benzene, 4[4-(6-hexadecaneoxy)phenylazo]pyridine and 4-(4-hydroxyphenylazo)-pyridine. The hydrogen bonding interaction in azo-systems were studied by Fourier transform infrared spectroscopy and for selected assembles by H-1 NMR technique. The obtained polyimide azo-assembles were characterized by X-ray diffraction and DSC measurements. H-bonds allow attaching a chromophore to each repeating unit of the polymer, thereby suppressing the macroscopic phase separation except for the systems based on 4-[4-(6-hydroxyhexyloxy)phenylazo]benzene. H-bonds systems were amorphous and revealed glass transition temperatures lower than for the polyimide matrixes (170-260 degrees C). The photoresponsive behavior of the azo-assemblies was tasted in holographic recording experiment. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Azobenzene
KW  - Polyimides
KW  - Photoinduced optical anisotropy
KW  - Surface relief grating
Y1  - 2015
U6  - https://doi.org/10.1016/j.optmat.2015.06.029
SN  - 0925-3467
SN  - 1873-1252
VL  - 47
SP  - 501
EP  - 511
PB  - Elsevier
CY  - Amsterdam
ER  -