The Characterization of Photoinduced Chirality in a Liquid-Crystalline Azo Polymer on Irradiation with Circularly Polarized Light

AbstractChiral nematic liquid crystalline films with fluorescent chromophores are capable of circularly polarized emission. A theory is presented in which the effects of anisotropic absorption and film thickness are accounted for. The predicted dissymmetry factor is compared with experimental data reported by Stegemeyer et al. and with the theory for the two limiting cases treated by Pollmann et al.

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Strategies to Stabilize the Photoinduced Supramolecular Chirality in Azobenzene Liquid Crystalline Polymers

Polymers ◽

10.3390/polym11050885 ◽

2019 ◽

Vol 11 (5) ◽

pp. 885 ◽

Cited By ~ 2

Author(s):

Jorge Royes ◽

Luis Oriol ◽

Rosa M. Tejedor ◽

Milagros Piñol

Keyword(s):

Block Copolymers ◽

Liquid Crystalline ◽

Room Temperature ◽

Temporal Stability ◽

Polarized Light ◽

Thermal Characterization ◽

Circularly Polarized Light ◽

Circularly Polarized ◽

Crystalline Polymers ◽

Supramolecular Chirality

This paper describes the synthesis, thermal characterization and optical properties of liquid crystalline homopolymers and block copolymers with a repeating unit consisting of two functional units, with at least one of them being an azobenzene. Films of these polymers have been irradiated with circularly polarized light at room temperature, evaluating the intensity of the photoinduced chiral signal and its temporal stability upon storage. The paper also explores two different strategies to restrict the relaxation of the photoinduced order. Firstly, block copolymers have been prepared to confine the photoaddressable segments into nanoscopic domains where relaxation should be restricted. Secondly, an alternative homopolymer has been synthesized where the repeating unit combines two chromophores that can be separately photoaddressed, an azobenzene unit to efficiently photoinduce chirality and a cinnamate to fix the chiral signal by photocrosslinking.

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Production and Characterization of Circularly Polarized Soft X-Rays for Materials Research at the ALS

MRS Proceedings ◽

10.1557/proc-437-73 ◽

1996 ◽

Vol 437 ◽

Author(s):

Anthony T. Young ◽

Jeffrey B. Kortright ◽

Zahid Hussain ◽

Vladimir Martynov ◽

Howard A. Padmore ◽

...

Keyword(s):

Polarized Light ◽

High Resolution Spectroscopy ◽

Experimental Program ◽

X Rays ◽

Circularly Polarized Light ◽

Circularly Polarized ◽

Materials Research ◽

Under Construction ◽

Polarized Radiation

AbstractThe experimental program at the Advanced Light Source to produce and characterize circularly polarized x-rays is described. A number of beamlines are either operating or under construction which produce circularly polarized light. Bend magnets, multilayer phase retarders, and insertion devices which directly produce circularly polarized radiation are described. These beamlines will have capabilities for both microscopy and high resolution spectroscopy. Measurements of the linear and circular polarization of these beamlines are also described.

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