New Liquid Crystalline Elastomeric Films Containing a Smectic Crosslinker: Chemical and Physical Properties

Abstract

Side-chain liquid crystal elastomers (SC-LCEs) have been designed by using a new smectic crosslinker. Two types of monodomain films were prepared based on polysiloxane chains, with a different relative concentration of both crosslinker and mesogenic comonomers. The mesomorphic behavior of the two SC-LCE systems was investigated by differential scanning calorimetry and polarized optical microscopy showing a different mesomorphic behavior: in one case, we obtained a nematic SC-LCE film, in the other case, a Smectic A SC-LCE film. In both systems, the mesophases were stable in a wide temperature range. Moreover, the SC-LCE films possess a relatively high orientation at room temperature. The physical-chemical properties, such as the local orientational ordering, structural organization, and dynamics of SC-LCEs’ constituents were studied by means of static and dynamic 2H NMR experiments, small-angle X-ray, and wide-angle X-ray diffractions. The relevant physical properties, such as the thermo-elastic and thermo-mechanic behaviors, are reported and discussed in view of the practical applications.

Recent Trends in Continuum Modeling of Liquid Crystal Networks: A Mini-Review

“…However, understanding the structural behavior of the material is not straightforward due to its multiphysics (e.g., stimuli-responsive structural change) and multiscale (e.g., scale difference in LC orientability between the macroscopic size of the structure) nature. Such modeling is particularly essential in LCN solids since numerous microscopic parameters affect phase transition [16,17], such as polymer chain length and network connectivity, and macroscopic parameters, including boundary conditions and the shape/topology of the structure, determine overall behavior.…”