Photo-responsive Diels–Alder-based azobenzene-functionalized main-chain liquid crystal networks

Light-responsive liquid crystal elastomer networks (LCNs) have received
significant interest due to their potential application in soft robotics
and shape-morphing devices. Here, we present a systematic examination of
light-responsive LCNs prepared using a catalyst-free Diels–Alder
cycloaddition and a new azobenzene functionalized monomer for main-chain
incorporation. The networks have robust mechanical stiffness that can be
reversibly modulated by 1 GPa by turning the UV light on and off. This
study highlights the contribution of photothermal softening to reversibly
control the rheological properties of the newly developed LCNs and
demonstrates the ability to tune the modulus on demand. We believe this
work will guide future developments of light-responsive LCNs based on the
newly developed Diels–Alder cycloaddition.