The Formation of Supramolecular Chiral Materials from Achiral Molecules Using a Liquid-Crystallin System: Symmetry Breaking, Amplification, and Transfer

Abstract

Recently, the formation of chiral materials by the self-organization of achiral small molecules has attracted much attention. How can we obtain chirality without a chiral source? Interesting approaches, such as mechanical rotation, circularly polarized light, and asymmetric reaction fields, have been used. We describe recent research developments in supramolecular chirality in liquid crystals, focusing primarily on our group’s experimental results. We present the following concepts in this review. Spontaneous mirror symmetry breaking in self-assembled achiral trimers induces supramolecular chirality in the soft crystalline phase. Two kinds of domains with opposite handedness exist in non-equal populations. The dominant domain is amplified to produce a homochiral state. Chirality is transferred to a polymer film during the polymerization of achiral monomers by using the homochiral state as a template. Finally, we discuss how the concepts obtained from this liquid crystal research relate to the origin of homochirality in life.

Ferroelectric Smectic Liquid Crystals

“…Niori et al discovered ferroelectric switching in a tilted smectic B2 phase of the achiral bent-core molecule P-n-O-PIMB in 1996 [14], and then Sekine et al suggested chirality in the smectic B2 phase [15]. These findings opened new avenues for the study of polar order and chiral superstructures in liquid crystals [16][17][18][19][20]. Ferroelectricity was observed in a uniaxial smectic A phase of a bent-core molecule [21].…”