Order–Disorder\nTransition of Supramolecular\nLiquid Crystalline Elastomers

Liquid crystalline elastomers (LCEs) are soft materials\nwhich disorder\nupon heating through the isotropic transition temperature. The order-disorder\nphase transition of LCEs results in a contraction of up to ∼50%\nalong the aligned axis. Motivated by this distinctive stimuli-response,\nLCEs are increasingly considered as low-density actuators. Generally,\nLCEs are composed entirely of covalent bonds. Recently, we have prepared\nLCEs with intramesogenic supramolecular bonds from dimerized oxybenzoic\nacid derivatives and documented distinctive thermomechanical response\nin these supramolecular LCEs. Here, we report a detailed investigation\nof phase transitions in supramolecular LCEs by systematically varying\nthe composition to affect the strength of the intermolecular interactions\nin the polymer network. The order-disorder phase transition is shown\nto be influenced by the conformation and dissociation of supramolecular\ndimers. Distinctly, this report isolates and details an LCE composition\nwhich undergoes an intermediate transition to an incommensurate phase\nat lower temperatures than the order-disorder transition.