Efficient light-induced phase transitions in halogen-bonded liquid crystals

Francisco Fernandez-Palacio, Mikko Poutanen, Marco Saccone*, Antti Siiskonen, Giancarlo Terraneo, Giuseppe Resnati, Olli Ikkala, Pierangelo Metrangolo, Arri Priimägi

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

42 Citations (Scopus)
476 Downloads (Pure)

Abstract

Here, we present a new family of light-responsive, fluorinated supramolecular liquid crystals (LCs) showing efficient and reversible light-induced LC-to-isotropic phase transitions. Our materials design is based on fluorinated azobenzenes, where the fluorination serves to strengthen the noncovalent interaction with bond-accepting stilbazole molecules, and increase the lifetime of the cis-form of the azobenzene units. The halogen-bonded LCs were characterized by means of X-ray diffraction, hot-stage polarized optical microscopy, and differential scanning calorimetry. Simultaneous analysis of light-induced changes in birefringence, absorption, and optical scattering allowed us to estimate that <4% of the mesogenic units in the cis-form suffices to trigger the full LC-to-isotropic phase transition. We also report a light-induced and reversible crystal-to-isotropic phase transition, which has not been previously observed in supramolecular complexes. In addition to fundamental understanding of light-responsive supramolecular complexes, we foresee this study to be important in the development of bistable photonic devices and supramolecular actuators.

Original languageEnglish
Pages (from-to)8314-8321
Number of pages8
JournalChemistry of Materials
Volume28
Issue number22
DOIs
Publication statusPublished - 22 Nov 2016
MoE publication typeA1 Journal article-refereed

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