Issue 4, 2020

Photo-induced guest–host interactions produce grain boundaries between smectic blocks

Abstract

Photo-induced isomerization of an azobenzene unit not only induces phase transition between two different phases but also brings marked changes in the physical properties of solids. We prepared a symmetric trimer possessing an azobenzene unit, 4,4′-bis{9-[4-(5-octylpyrimidin-2-yl)phenyloxy]nonyloxy}azobenzene (I), and investigated the phase transition behaviour of trimer I and that of its binary mixture with a host liquid crystal. Trimer I exhibited three crystalline phases on cooling. Photo-induced isothermal crystal–liquid transition occurred only in the highest temperature crystalline phase through the transcis isomerization of the azobenzene unit. A binary mixture of trimer I (20 wt%) and a host liquid crystal (80 wt%) was found to exhibit grain boundaries consisting of nematic liquid crystals between smectic C blocks during a cooling process under UV irradiation. We explain the phase separation in terms of guest–host interactions between the photoinduced cis-trimer and its surrounding host liquid-crystalline molecules.

Graphical abstract: Photo-induced guest–host interactions produce grain boundaries between smectic blocks

Supplementary files

Article information

Article type
Paper
Submitted
30 Mar 2020
Accepted
17 Jun 2020
First published
17 Jun 2020
This article is Open Access
Creative Commons BY license

Mater. Adv., 2020,1, 899-907

Photo-induced guest–host interactions produce grain boundaries between smectic blocks

A. Yoshizawa and S. Obata, Mater. Adv., 2020, 1, 899 DOI: 10.1039/D0MA00145G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements