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

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 H-2 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.

Automated summary

Side-chain liquid crystal elastomers (SC-LCEs) were designed using a new smectic crosslinker. Two types of monodomain films were prepared based on polysiloxane chains with different concentrations of crosslinker and mesogenic comonomers. Differential scanning calorimetry and polarized optical microscopy were used to investigate the mesomorphic behavior of the two SC-LCE systems, revealing different mesophases. The physical-chemical properties of SC-LCEs were studied using various techniques, and their thermo-elastic and thermo-mechanic behaviors were discussed for potential practical applications.