TY - JOUR
T1 - Efficient light-induced phase transitions in halogen-bonded liquid crystals
AU - Fernandez-Palacio, Francisco
AU - Poutanen, Mikko
AU - Saccone, Marco
AU - Siiskonen, Antti
AU - Terraneo, Giancarlo
AU - Resnati, Giuseppe
AU - Ikkala, Olli
AU - Metrangolo, Pierangelo
AU - Priimagi, Arri
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/11/22
Y1 - 2016/11/22
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84997824561&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.6b03460
DO - 10.1021/acs.chemmater.6b03460
M3 - Article
SN - 0897-4756
VL - 28
SP - 8314
EP - 8321
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 22
ER -