Besides fulgides, diarylethenes, spiropyrans, and spirooxazines, azobenzene
molecules have drawn a great deal of attention in combination with liquid
crystalline polymers since their synthetic versatility and the promesogenic
shape of the thermodinamically stable trans isomer that allows to keep the liquid
crystalline phase of the material, in which they are incorporated. The bent shape
shown by the light-induced cis isomer strongly distorts the liquid crystalline
character of the polymer in which the chromophore is incorporated and can
lead to important changes of the material morphology and macroscopic
properties.
Rational design of the liquid crystalline polymeric photoresponsive materials
has been carried out to exploit their potential in very diverse fields of application.
Photoresponsive systems have been optimized due to their potential in (holographic) optical storage. Photoinduced generated surface relief structures with
interest in photonic applications have been explored. Photoalignment is being
studied as a tool to generate periodic patterns at the nanoscale with interest in
nanolithography. Finally, macroscopic motions of film of these materials have
shown their potential to generate new robotic functions for soft actuators.
Keywords
Photoresponsive materials · Light-induced effects · Liquid crystalline polymers ·
Azobenzene
Definition
Photoresponsive liquid crystalline polymers combine the ability of self-organization
of mesomorphic materials, the physicochemical properties of macromolecular compounds, and the light response provided by photoisomerizable units incorporated in
the material. Light applied to these systems induces transformations and motions of
the photosensitive units that can lead, through cooperative effects of liquid crystalline polymeric systems, to large modifications of material properties. These changes
include light-induced macroscopic optical anisotropy, changes in optical transmission due to phase transitions or dimensional variations of the material among others
with potential use in information and communication technologies and biomedical
applications.
Introduction
Liquid Crystalline Polymers (LCPs) lie at the intersection between Liquid Crystal
(LC) and Polymer Science. LCPs combine the presence of mesogenic units and a
macromolecular architecture. As a result they share features with both types of
materials, such as long-range orientational order of the constituent mesogens, anisotropic macroscopic properties, and cooperativity from LCs and the ease of
448
C. Sánchez-Somolinos
molecules have drawn a great deal of attention in combination with liquid
crystalline polymers since their synthetic versatility and the promesogenic
shape of the thermodinamically stable trans isomer that allows to keep the liquid
crystalline phase of the material, in which they are incorporated. The bent shape
shown by the light-induced cis isomer strongly distorts the liquid crystalline
character of the polymer in which the chromophore is incorporated and can
lead to important changes of the material morphology and macroscopic
properties.
Rational design of the liquid crystalline polymeric photoresponsive materials
has been carried out to exploit their potential in very diverse fields of application.
Photoresponsive systems have been optimized due to their potential in (holographic) optical storage. Photoinduced generated surface relief structures with
interest in photonic applications have been explored. Photoalignment is being
studied as a tool to generate periodic patterns at the nanoscale with interest in
nanolithography. Finally, macroscopic motions of film of these materials have
shown their potential to generate new robotic functions for soft actuators.
Keywords
Photoresponsive materials · Light-induced effects · Liquid crystalline polymers ·
Azobenzene
Definition
Photoresponsive liquid crystalline polymers combine the ability of self-organization
of mesomorphic materials, the physicochemical properties of macromolecular compounds, and the light response provided by photoisomerizable units incorporated in
the material. Light applied to these systems induces transformations and motions of
the photosensitive units that can lead, through cooperative effects of liquid crystalline polymeric systems, to large modifications of material properties. These changes
include light-induced macroscopic optical anisotropy, changes in optical transmission due to phase transitions or dimensional variations of the material among others
with potential use in information and communication technologies and biomedical
applications.
Introduction
Liquid Crystalline Polymers (LCPs) lie at the intersection between Liquid Crystal
(LC) and Polymer Science. LCPs combine the presence of mesogenic units and a
macromolecular architecture. As a result they share features with both types of
materials, such as long-range orientational order of the constituent mesogens, anisotropic macroscopic properties, and cooperativity from LCs and the ease of
448
C. Sánchez-Somolinos