Spontaneous symmetry breaking and emergent polar order are each of fundamental importance to a range of scientific disciplines, as well as generating rich phase behaviour in liquid crystals (LCs). Here, we show the union of these phenomena to lead to two previously undiscovered polar liquid states of matter. Both phases have a lamellar structure with an inherent polar ordering of their constituent molecules. The first of these phases is characterised by polar order and a local tilted structure; the tilt direction processes about a helix orthogonal to the layer normal, the period of which is such that we observe selective reflection of light. The second new phase type is anti-ferroelectric, with the constituent molecules aligning orthogonally to the layer normal. This has led us to term the phases the $${{{{{\rm{Sm}}}}}}{{{{{{\rm{C}}}}}}}_{{{{{{\rm{P}}}}}}}^{{{{{{\rm{H}}}}}}}$$Sm C P H and SmA_AF phases, respectively. Further to this, we obtain room temperature ferroelectric nematic (N_F) and $${{{{{\rm{Sm}}}}}}{{{{{{\rm{C}}}}}}}_{{{{{{\rm{P}}}}}}}^{{{{{{\rm{H}}}}}}}$$Sm C P H phases via binary mixture formulation of the novel materials described here with a standard N_F compound (DIO), with the resultant materials having melting points (and/or glass transitions) which are significantly below ambient temperature. The new soft matter phase types discovered herein can be considered as electrical analogues of topological structures of magnetic spins in hard matter.

The discovery of fluid states of matter with spontaneous bulk polar order is appreciated as a major discovery in the fields of soft matter and liquid crystals. Typically, this manifests as polar order superimposed atop conventional phase structures and is thus far limited to orthogonal phase types. Here we report a family of materials which exhibit a previously unseen state of matter which we conclude is a polar smectic C phase, and so we term it SmC _P . The spontaneous polarisation of the SmC _P phase is over two orders of magnitude larger than that found in conventional ferroelectric SmC phase of chiral materials used in some LCD devices. Fully atomistic molecular dynamics simulations faithfully and spontaneously reproduce the proposed structure and associated bulk properties; comparison of experimental and simulated X‐ray scattering patterns shows excellent agreement. The materials disclosed here have significantly smaller dipole moments than typical polar liquid crystals such as RM734 which suggests the role of molecular electrical polarity in generating polar order is perhaps overstated, a view supported by consideration of other molecular systems.

A series of liquid crystal (LC) materials are reported, which form a variety of ferroelectric nematic and smectic phases. The relationship between the number and position of lateral fluorine substituents and the formation of ferroelectric LC phases is investigated. While the addition of fluorine substituents increases the temperature at which ferroelectric order appears, the relationship between fluorination and the LC phase sequence is more complicated. Introducing lateral fluorine substituents can either suppress or promote the formation of ferroelectric smectic phases, depending on their position within the molecule, and the interplay between these trends allows for more exotic ferroelectric phases to appear.

The recent discovery of spontaneous chiral symmetry breaking has demonstrated the possibility of discovering the exotic textures of ferromagnetic systems in liquid crystalline fluid ferro-electrics. We show that the polar smectic mesophase exhibited by the first molecule discovered to exhibit a spontaneously chiral ferroelectric nematic phase is also helical has a strongly varied textural morphology depending in its thermal history and phase ordering. Electro-optic studies demonstrate that the two spontaneously chiral phases exhibit field-induced phase transitions. For the nematic variant, this process is threshold-less and has no hysteresis, while for the smectic it has a clear threshold and shows hysteresis meaning this phase exhibits pseudo-ferrielectric switching, the first of its kind for ferroelectric nematic like phases. We show that helix formation can be both 1st and 2nd order, but when it is 1st it is accompanied by pre-transitional helix formation extending from the phase boundary into the preceding ferroelectric nematic phase.

The spontaneous long-range mutual orientation of their electric dipole moments that gives rise to polar liquid crystals is shown to result from subtle intermolecular interactions.

Herein it is reported the first examples of reactive mesogenic materials (RMs) which exhibit fluid ferroelectric order based on the recently discovered ferroelectric nematic (N_F) phase. These materials N_F RMs and they provide the first steps toward the next generation of ferroelectric liquid crystalline polymer networks is termed. The chemical synthesis and characterization of the liquid crystalline properties of these materials is reported, demonstrating that they have the lowest longitudinal molecular dipole moments (µ) of any reported N_F material of 7.39 D. It is go on to demonstrate a potential use case of this new class of reactive material through the polymer stabilization of a matrix which exhibits the N_F phase, increasing the phase range of the ferroelectric phase from 75 to 120 °C. The N_F RMs reported herein are an exciting step forward in ferroelectric liquid crystal research, demonstrating that reactive N_F materials are achievable, allowing for the future development of liquid crystalline ferroelectric networks, elastomers and polymers.