In 2017-2018 liquid crystal research groups working independently in the UK and Japan, exploring two distinct families of rod-shaped organic molecules, each reported an unknown nematic-like liquid crystal phases in their materials. In 2020 we showed that the unknown phase in the UK compound, RM734, was a ferroelectric nematic: a 3D liquid phase with a fluid spontaneous polarization field, P. This was a notable event in LC science because ferroelectricity was put forth in the 1910’s, by Peter Debye and Max Born, as a possible stabilizing mechanism for the nematic phase. Nematic polar ordering was revisited extensively experimentally since that time, in systems ranging from colloidal suspensions of rods or discs, to main chain polymers, and melts of polar molecules, and claimed but has never established with certainty. Following on we found, in mixtures of RM734 with the Japanese compound DIO, that the unusual phase in DIO was actually the same ferroelectric nematic as in RM734. This convergence moved us to coin the notion “Ferroelectric Nematic Realm,” for what saw for potential as a new soft matter subfield. With two molecules and one phase this wasn’t much of a Realm, but now it has grown to ~500 molecules, making ~15 new phases, and exhibiting a growing body of exotic LC phenomenology. I will present some of the highlights of the chemical physics and applications of this fundamentally new kind of fluid.
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