The research group of Professor Takashi Kajitani and Professor Takanori Fukushima of Tokyo Institute of Technology spontaneously formed droplets with a regular structure like a single crystal of chiral molecules (Note) without disturbing the structural order. I discovered the phenomenon of flowing while rotating in one direction.This achievement is a result of joint research with the Institute of Materials Structure Science, RIKEN, Tohoku University, JEOL RESONANCE Co., Ltd., and the University of Tokyo.
The research group synthesized a derivative in which a chiral side chain was introduced into a substance called "triphenylene hexacarboxylic acid ester", and investigated its phase transition behavior and aggregate structure.In the intermediate phase of this substance (a phase existing between gas, liquid, and solid), two-dimensional sheets of "herringbone structure" made by continuously combining V-shapes and rectangles vertically and horizontally are stacked, as if it were a single crystal. It formed a three-dimensional structure.Its ability to form regular structures was at least a few millimeters, and on the molecular scale it could be regarded as a spontaneously assembled "ultra" long-range structural order.
This droplet-like substance showed a fluidity of flowing downward when the substrate was erected, and the structural regularity in the droplet was not impaired at all even in the process of flowing down.A detailed examination revealed that the "property to solidify" and the "property to flow" maintain an exquisite balance.Furthermore, it was also found that the droplet rotates in one direction when it flows down, and the direction of rotation is determined by the chirality (R-body or S-body) of the side chain introduced into triphenylene.
The substance discovered this time is a substance that overturns the common wisdom that it is not a crystal, liquid crystal, or liquid, and gives new insights on the correlation between molecular chirality and molecular macroscopic collective motion.In the future, it is expected that the elucidation of the mechanism will lead to the development of physical chemistry related to new molecular aggregates and the innovation of high-performance organic materials.
(Note) Molecules with the property of chirality (palm) that cannot be superimposed on the mirror image, such as the left and right hands.
Paper information:[Nature Materials] Chiral crystal-like droplets displaying unidirectional rotational sliding
