Fluid fibres in true 3D ferroelectric liquids

We demonstrate an exceptional ability of a high-polarisation 3D ferroelectric liquid to form freely-suspended fluid fibres at room temperature. Unlike fluid threads in modulated smectics and columnar phases, where translational order is a prerequisite for forming liquid fibres, recently discovered ferroelectric nematic forms fibres with solely orientational molecular order. Additional stabilisation mechanisms based on the polar nature of the mesophase are required for this. We propose a model for such a mechanism and show that these fibres demonstrate an exceptional non-linear optical response and exhibit electric field-driven instabilities.