A Nanohelicoidal Nematic Liquid Crystal Formed by a Non-Linear Duplexed Hexamer

Area of Science:

• Materials Science
• Liquid Crystals
• Supramolecular Chemistry

Background:

• The twist-bend (TB) nematic phase in liquid crystals is characterized by a nanometre-scale helical pitch and spontaneous mirror symmetry breaking.
• This phase was previously thought to require achiral materials with linearly connected mesogenic units.

Purpose of the Study:

• To investigate if non-linear molecular architectures can induce the twist-bend nematic phase.
• To challenge the established prerequisites for TB phase formation.

Main Methods:

• Synthesis of non-linear oligomers, specifically H-shaped hexamesogens.
• Characterization of the liquid crystalline phases exhibited by these new materials using standard techniques.

Main Results:

• Non-linear H-shaped hexamesogens were found to exhibit both nematic and twist-bend nematic phases.
• This demonstrates that a linear sequence of mesogenic units is not essential for the TB phase.
• The findings support the double helix model over the simple heliconical model for the TB phase.

Conclusions:

• The formation of the twist-bend nematic phase is possible in a wider range of self-assembling structures than previously assumed.
• This discovery opens avenues for new low-molecular-weight liquid crystalline materials.
• The results provide crucial evidence supporting specific theoretical models of the TB phase.