Carbohydrate rod conjugates: ternary rod-coil molecules forming complex liquid crystal structures

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Liquid Crystals

Background:

• T-shaped polyphilic triblock molecules combine rodlike, hydrophilic, and lipophilic segments.
• Understanding their self-organization is key to designing advanced materials.

Purpose of the Study:

• Synthesize novel T-shaped polyphilic triblock molecules.
• Investigate their thermotropic liquid crystalline behavior and self-organization modes.
• Explore the influence of molecular structure on phase formation.

Main Methods:

• Palladium-catalyzed cross-coupling reactions for synthesis.
• Polarized light microscopy, differential scanning calorimetry (DSC), and X-ray scattering for characterization.
• Systematic variation of polar and lipophilic segment lengths.

Main Results:

• Discovery of unusual liquid crystalline phases, including hexagonal channeled layer (ChL(hex)) and honeycomb-like networks (square/pentagonal cylinders).
• Observation of a hexagonal columnar phase with tangential terphenyl core organization.
• Birefringence reversal in one compound due to terphenyl core reorientation.
• Induction of lamellar phases upon addition of protic solvents.

Conclusions:

• Molecular architecture dictates complex self-organization into unique 3D periodic liquid crystalline phases.
• These materials exhibit diverse phase behaviors dependent on segment lengths and solvent interactions.
• The findings offer insights into designing materials with tailored supramolecular structures.