arXiv subjects

Calum J Gibb

Publications and source records attributed to Calum J Gibb.

3 recordsLinked to original sources

arXiv2026

Broken Inversion Symmetry via a Magic Methyl Effect

Polar liquid crystals - fluid phases in which molecular dipoles organise into ferro- or antiferroelectric states - present a highly constrained molecular design space, where small changes can entirely suppress polar organisation. Here we demonstrate, contrary to expectations, that installation of a methyl group in the 5-position of a 1,3-dioxane ring substantially increases the onset temperature of polar order. Remarkably, this effect proves transferable across several liquid-crystal families, including examples where the methylated derivative exhibits a polar phase whereas its parent compound does not. Across 8 matched pairs, we find that a 5-methyl group can enhance the onset temperature of polar order in 1,3-dioxane materials by up to 120 °C. These findings establish a simple and general molecular design strategy for enhancing and enabling spontaneous dipolar ordering in liquid crystals.

cond-mat.mtrl-sci↗

arXiv2026

Design Principles for Fluid Molecular Ferroelectrics

Fluid molecular ferroelectrics are a new class of organic materials where ferroelectricity is found in conjunction with 3D fluidity whilst still retaining spontaneous polarization values comparable to their traditional solid state counterparts. One of the major challenges for soft condensed matter physics is predicting whether a fluid molecular material will form ferroelectric phase with nematic or smectic order. Through the synthesis of forty five systematically varied molecules, and by analogy to solid molecular ferroelectrics, is it shown that subtle hydrogen fluorine substitution allows for tuneable syn-parallel pairing motifs resulting in either specific pairings leading too geometrically constrained lamellar order or diversified pairings stabilising nematic ordering. Large-scale, fully atomistic molecular dynamics simulations reveal that smectic ferroelectricity emerges from discrete lateral pairing modes, whereas nematic phases arise from a multiplicity of equivalent polar configurations. Together, these findings establish experimentally validated design principles for fluid molecular ferroelectrics and provide a predictive framework for engineering functional polar fluids.

cond-mat.soft↗

arXiv2025

Reactive Fluid Ferroelectrics: A Gateway to the Next Generation of Ferroelectric Liquid Crystalline Polymer Networks

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

cond-mat.mtrl-sci↗