Direct experimental observation of the layered structure of ferroelectric and antiferroelectric smectic liquid crystals by neutron reflectometry

Longitudinally polar liquid crystals posses 3D orientational order coupled with unidirectional electric polarity, yielding fluid-like ferroelectrics with spontaneous polarizations comparable to solid state ferroelectrics. In the past year, multiple new polar lamellar phases have been discovered showing ferroelectric, anti-ferroelectric and more complex polar ordering. Despite research being in its infancy, possible applications for these fascinating new states of matter are already being suggested including non-linear optical devices, entangled photon generation and photo variable capacitors. As of yet, the specific structure of these phases is not particularly well understood prohibiting device optimisation for any application. Neutron reflectometry would allow the layered structure of these material to be probed directly, studying the polar orientation of the molecules, yielding a greater understanding of this new class of soft materials.