We study bicomponent systems where one component represents a liquid crystalline (LC) phase, and the other component randomly perturbs the LC order. Such systems can serve as a testbed to systematically analyse the impact of qualitatively different types of random-type sources of perturbation on the orientational and/or translational order. This mini-review presents typical representatives of such systems, where orientational and translational order is probed in nematic and smectic A LCs, respectively. As a source of perturbation, we consider either different porous matrices (control-pore glass, aerogels) or aerosil nanoparticles, which can form in LCs' different fractal-like network organizations. In such complex systems, LC ordering fingerprints the interplay among LC elastic forces, interfacial forces, and randomness. The resulting LC behaviour could be characterised by either long-range, quasi long-range, or short-range order. We demonstrate under which conditions random-field-like phenomena or interfacial effects dominate. However, these effects are relatively strongly entangled in most experimental systems, and individual impacts cannot be precisely identified.

Graphical abstract

中文翻译：

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随机场型无序对向列液晶结构的影响

我们研究双组分系统，其中一个组分代表液晶 (LC) 相，而另一个组分随机扰乱 LC 顺序。这样的系统可以作为一个测试平台，系统地分析不同类型的随机扰动源对定向和/或平移顺序的影响。这篇小型评论介绍了此类系统的典型代表，其中分别在向列型和近晶型 A LC 中探索了定向和平移顺序。作为扰动的来源，我们考虑不同的多孔基质（控制孔玻璃、气凝胶）或气硅纳米颗粒，它们可以在 LC 的不同分形网络组织中形成。在这样的复杂系统中，LC 排序指纹识别了 LC 弹性力、界面力和随机性之间的相互作用。由此产生的 LC 行为可以通过远程、准远程或短程顺序来表征。我们展示了在哪些条件下类随机场现象或界面效应占主导地位。然而，这些影响在大多数实验系统中都相对强烈地纠缠在一起，并且无法精确识别个体影响。

图形概要