Supramolecular organization of block oligomers based on rod-shaped mesogen into liquid crystalline assembly

The development of novel supramolecular materials with nanometer-scale architectures and the effect of these architectures on the materials' properties are presently of great interest in molecular design. Liquid crystalline assemblies of rod like mesogenic molecules containing flexible coils (rod-coil molecules) provide a facile entry into this area. Rod-coil molecules are demonstrated to self-assemble into a rich variety of different liquid crystalline structures of nanoscale dimensions through the combination of shape complementarity and repulsive interaction of rigid and flexible parts as an organizing force. The mesophases include smectic, hexagonal columnar, bicontinuous cubic, honeycomb like and discrete micellar phases. The unconventional mesophases are induced by changing the rod to coil volume fraction, by controlling the number of rod-coil repeating units and by increasing the rod-coil molecular length. Additionally, the liquid crystalline structures of rod-coil molecules are also discussed with respect to their manipulation by complexation of polyether chains with lithium cations or addition of polar solvent, from lamellar, bicontinuous cubic to hexagonal columnar mesophases.