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A New Order of Liquids: Polar and ferroelectric orientationally modulated soft materials

液体的新秩序：极性和铁电取向调制软材料

基本信息

批准号：
MR/W006391/1
负责人：
Richard Mandle
金额：
$ 154.09万
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=MR%2FW006391%2F1
关键词：
New Order Liquids Polar ferroelectric

项目摘要

Liquid crystals (LC) combine liquid-like fluidity with some of the optical properties of crystalline materials (such as birefringence). Nematic liquid crystals are those in which the constituent molecules (or particles) have orientational order, (i.e. they align roughly parallel or antiparallel) but lack positional order. It is nematic LCs that underpin modern liquid crystal display (LCD) technology which is now ubiquitous to the point of being invisible in our daily lives, and via which you are perhaps reading this document. Other types of nematic liquid crystal had been the subject of intense speculation but eluded experimental discovery: notably, ferroelectric nematics were predicted independently by Peter Debye and Max Born, both Nobel laureates, in the early 20th century. Ferroelectricity, in which a material exhibits a permanent electric polarization (PS) which varies in strength under an applied electric field, is typically weak in organic and/or fluid materials and only approaches application-ready levels in ceramics, which can be brittle, difficult to fabricate, and costly.The discovery of new nematic ground states is rare; the discovery of the twist-bend nematic phase (NTB) in 2011 was the first new nematic state in over a century. The NTB phase features nematic molecular ordering which oscillates periodically, hence, it is known as a modulated nematic. Recently I discovered the second known modulated nematic phases, the splay-nematic (NS); this phase is formed when wedge shaped molecules organise themselves into a structure reminiscent of an array of Japanese fans arranged head-to-tail. This head-tail ordering makes the NS phase is the first - and to date only - bona fide example of a ferroelectric nematic. The values of PS of NS materials rival those of solid materials but retain the fluidity of a liquid, conferring two principal advantages; materials processing is simplified, and there is much increased tolerance to mechanical force (self-healing) due to the fluidity of the active medium. The remarkable electric-field response of the NS phase has the potential to remake nematic based technology anew, enabling transformative applications utilising these soft materials: potential areas of benefit include temperature regulation via the electrocaloric effect, and computing via ferroelectric random-access memory and field effect transistors. One key advantage of NS materials is that they can use existing processing/alignment technologies developed for existing LCD technology, significantly lowering the barrier to future applications. The NS phase is such a recent discovery that new research is required to engineer the properties of materials that exhibit this phase in order to realise their unrivalled potential by: reducing their high operating temperatures, increasing their short working temperature ranges, and improving their stability (chemical and thermal). The design of new materials to satisfy these requirements is non-trivial, and complicated by a need to develop our understanding of the relationship between the incidence of these phases of matter and molecular structure. This Fellowship will deliver a paradigm shift in our understanding of the chemistry and physics that underpins modulated nematics. The growth in knowledge required will arise from linking molecular design (chemistry) with molecular modelling (chemistry/physics), and material characterisation (physics). As the discoverer of the NS phase with a background in both sciences I am uniquely placed to lead this research from scientific curiosity towards real-world application. I will develop materials with superior properties and growing our understanding of the molecular features that drive the incidence of this phase. My research will deliver materials for real world applications while also adding entirely new chapters to the rulebook on liquid crystals, and will set the research agenda in liquid crystals and soft matter in the decades to come

液晶（LC）联合收割机将液体状流动性与晶体材料的一些光学性质（例如双折射）结合。向列型液晶是其中组成分子（或颗粒）具有取向顺序（即它们大致平行或反平行排列）但缺乏位置顺序的那些。液晶显示器是现代液晶显示器（LCD）技术的基础，该技术现在在我们的日常生活中无处不在，以至于不可见，并且您可能正在通过该技术阅读本文档。其他类型的铁电液晶一直是人们激烈猜测的对象，但却没有通过实验发现：值得注意的是，铁电向列相是由诺贝尔奖得主彼得·德拜和马克斯·玻恩在世纪初独立预测的。铁电性（其中材料在施加的电场下表现出强度变化的永久电极化（PS））在有机和/或流体材料中通常是弱的，并且仅在陶瓷中接近可应用水平，陶瓷可能是脆性的、难以制造并且昂贵。在2011年发现的扭曲-弯曲相变（NTB）是世纪以来第一个新的相变。NTB相的特征是具有周期性振荡的有序分子，因此，它被称为调制有序。最近，我发现了第二个已知的调制的双相，splay-双相（NS）;当楔形分子将自己组织成一种结构时，就会形成这种相位，让人想起日本扇子首尾排列的阵列。这种首尾有序使得NS相成为第一个--也是迄今为止唯一一个--铁电晶体的真正例子。NS材料的PS值与固体材料的PS值相媲美，但保留了液体的流动性，这赋予了两个主要优点：材料加工简化，并且由于活性介质的流动性，对机械力的耐受性大大增加（自修复）。NS相的显着电场响应有可能重新改造基于软材料的技术，使这些软材料的变革性应用成为可能：潜在的受益领域包括通过电热效应进行温度调节，以及通过铁电随机存取存储器和场效应晶体管进行计算。NS材料的一个关键优势是，它们可以使用为现有LCD技术开发的现有加工/对准技术，大大降低了未来应用的障碍。NS相是一个最近的发现，需要进行新的研究来设计表现出这种相的材料的特性，以便通过降低其高工作温度，增加其短工作温度范围，并提高其稳定性（化学和热）来实现其无与伦比的潜力。满足这些要求的新材料的设计是不平凡的，并且由于需要发展我们对物质的这些相的发生率与分子结构之间的关系的理解而变得复杂。这个奖学金将提供一个范式转变，在我们的理解的化学和物理基础调制向列。所需知识的增长将来自分子设计（化学）与分子建模（化学/物理）和材料表征（物理）的联系。作为具有两门科学背景的NS阶段的发现者，我处于独特的位置，可以领导这项研究从科学好奇心走向现实世界的应用。我将开发具有优异性能的材料，并加深我们对推动这一阶段发生的分子特征的了解。上级材料。我的研究将为真实的世界应用提供材料，同时也为液晶的规则手册增添了全新的篇章，并将在未来几十年内设定液晶和软物质的研究议程