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This document is a foreword for a volume of the Journal of Elasticity dedicated to the memory of Jerald LaVerne Ericksen. Ericksen made significant contributions to the field of mechanics of materials, particularly in the study of nonlinear material behavior. His research influenced various areas of continuum mechanics, including rheology, elasticity, viscoelasticity, and thermomechanics. The foreword also highlights Ericksen's personal qualities, such as his kindness, simplicity, and dedication to education. The volume includes portraits, essays, and research papers that showcase Ericksen's impact and legacy. The document concludes with acknowledgments and a note from the publishers. [Extracted from the article]

It has become clear that superior material functions are derived from precisely controlled nanostructures. This has been greatly accelerated by the development of nanotechnology. The next step is to assemble materials with knowledge of their nano-level structures. This task is assigned to the post-nanotechnology concept of nanoarchitectonics. However, nanoarchitectonics, which creates intricate three-dimensional functional structures, is not always easy. Two-dimensional nanoarchitectonics based on reactions and arrangements at the surface may be an easier target to tackle. A better methodology would be to define a two-dimensional structure and then develop it into a three-dimensional structure and function. According to these backgrounds, this review paper is organized as follows. The introduction is followed by a summary of the three issues; (i) 2D to 3D dynamic structure control: liquid crystal commanded by the surface, (ii) 2D to 3D rational construction: a metal–organic framework (MOF) and a covalent organic framework (COF); (iii) 2D to 3D functional amplification: cells regulated by the surface. In addition, this review summarizes the important aspects of the ultimate three-dimensional nanoarchitectonics as a perspective. The goal of this paper is to establish an integrated concept of functional material creation by reconsidering various reported cases from the viewpoint of nanoarchitectonics, where nanoarchitectonics can be regarded as a method for everything in materials science. [ABSTRACT FROM AUTHOR]

The development of multimode photopatterning systems based on supramolecular coordination complexes (SCCs) is considerably attractive in supramolecular chemistry and materials science, because SCCs can serve as promising platforms for the incorporation of multiple functional building blocks. Herein, we report a light‐responsive liquid‐crystalline metallacycle that is constructed by coordination‐driven self‐assembly. By exploiting its fascinating liquid crystal features, bright emission properties, and facile photocyclization capability, a unique system with spatially‐controlled fluorescence‐resonance energy transfer (FRET) is built through the introduction of a photochromic spiropyran derivative, which led to the realization of the first example of a liquid‐crystalline metallacycle for orthogonal photopatterning in three‐modes, namely holography, fluorescence, and photochromism. [ABSTRACT FROM AUTHOR]

Liquid Crystals are thought of as being complex fluids, underpinned by self‐assembly and self‐organisation within partially ordered fluids, and which sit between solid and liquid states of matter. The realm of the field stretches from low molar mass to polymeric materials, from organic to inorganic substances, and from being functional materials to biological organelles. In this article, we explore the cusp of the change over from nano‐ to macro‐sciences through the formation of 'supermolecular' systems, and we debate if such materials are in fact oligomers or materials having giant molecules possessing discrete chemical constitutions? We performed this investigation by synthesising mesogenic materials based upon difluoroterphenyls, terminally substituted with a chiral motif based on (S)‐2‐octanol, and which could be appended onto a variety of siloxane scaffolds. We studied the structures and properties of six mesomorphic materials in which we systematically increased the number of mesogenic units attached to the scaffold. [ABSTRACT FROM AUTHOR]

An important aspect of modern materials science is discussed, specifically, the possibility of combining inorganic nanoparticles and liquid crystals in composites. These systems make it possible to combine the liquid-crystal properties of a matrix with the luminescent properties of quantum dots. A five-component mixture consisting mainly of 4-cyanobiphenyl derivatives has been used as a matrix. Substitution of derivatives of organic acids for ligands formed during the synthesis of quantum dots is demonstrated. Chiralization of a nematic matrix and the possibility of introducing quantum dots into it are demonstrated by the example of two new optically active ligands. [ABSTRACT FROM AUTHOR]

Liquid crystals have numerous applications in various fields ranging from drug delivery, gene therapy in biosciences to electronic display and sensors in the field of opt-electronics and material science. In recent years, the properties of liquid crystals have been tailored by truncating the terminal atom(s) or group of atoms and/or by doping different types of nanomaterials; such as nanodots, nanorods, nanotubes, nanoplatelets, etc. Controlled assembly of nanoparticles in liquid crystal media can provide an alternative method to tailor new and desired opto-electronic properties in uniquely arranged quantum dots. This self-assembly of nanoparticles produces new hybrid (composite) materials having large number of applications. Here, we review different applications of nanoparticles and liquid crystal systems and highlight different approaches for achieving the hierarchical arrangement of nanoparticles in liquid crystal media. Here, phenomena like quantum dot self-assembly, formation of hollow microstructures, memory effect, and formation of microcapsules, etc. in presence of liquid crystal media are revisited and discussed critically. Band-gap-tailoring has emerged as a major thrust area because of numerous applications in making opto-electronic devices. Band-gap of liquid crystals can be also be tailored either by doping (metal) atoms or by nucleating their nano-clusters after removing their terminal groups. This phenomenon creates a lot of attraction among scientists. Hierarchical arrangement of nano-dots in liquid crystal media has gained a lot of interest, as they can possess special functional properties; many of which are known whereas many others need to be discovered. Hierarchical arrangement of nano-clusters can be obtained either by doping atoms into liquid crystals followed by a nucleation process or by forming molecular architectures by weak coupling between quantum dots because of van der Waal forces. Functional properties such as magnetic, physiochemical, and opto-electronic properties of the hybrid systems are different from their constituent parts, and thus the hybrid systems can find a vital role in the field of nanoscience and nanotechnology. Because of the aforesaid reasons, it has gained much attention in the last few decades. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesized and characterized cholesterol derivatives with thiazole moiety. • Conducted antimicrobial and antioxidant evaluations of the derivatives. • Evaluated liquid crystalline properties, revealing a chiral nematic mesophase. • Performed thermal investigations using DSC and TGA, alongside DFT calculations. • Conducted comprehensive UV–visible and photoluminescence studies, including PL quantum yield analysis. This study presents the synthesis and comprehensive characterization of novel thiazole Schiff's base compound linked to various substituted formylphenyl cholesteryl carbonates. The structures were confirmed by elemental analysis and 1H NMR, 13C NMR, and FT-IR spectroscopy. Optical texture investigations revealed that only compound 7a exhibited liquid crystalline behaviour, specifically showing a chiral nematic (N*) mesophase. Thermal properties were analyzed using differential scanning calorimetry (DSC) showing phase transitions, and thermogravimetric analysis (TGA) indicating their stability ranging from 223 to 361 °C. The compound 7a exhibited significant antibacterial activity with zone of inhibition of 18 mm for Staphylococcus aureus (gram-positive) and 25.5 mm for Escherichia coli (gram-negative), and compound 7a and 8 displayed highest antifungal activity with zone of inhibition of 17.5 mm and 24.5 mm against Aspergillus niger and Candida albicans , respectively. Antioxidant activity was assessed using the DPPH assay, where compound 8 showed superior scavenging activity with IC 50 value of 101.32 µg/mL. Additionally, the compounds were UV-active and exhibited photoluminescence, showing emission peaks ranging from 412 to 434 nm and a quantum yield of 0.11 to 0.23. In silico predictions indicated promising drug-likeness and bioactivity scores. Density Functional Theory (DFT) calculations provided insights into the electronic properties and molecular interactions. This research highlights the potential of these thiazole Schiff base derivatives for applications in pharmaceuticals and materials science, contributing valuable data on their multifunctional properties. [ABSTRACT FROM AUTHOR]

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Azobenzene derivatives have become one of the most famous photoresponsive chromophores in the past few decades for their reversible molecular switches upon the irradiation of actinic light. To meet the ever-increasing requirements for applications in materials science, biomedicine, and light-driven devices, it is usually necessary to adjust their photochemical property from the molecular level by changing the substituents on the benzene rings of azobenzene groups. Among the diverse azobenzene derivatives, azopyridine combines the photoresponsive feature of azobenzene groups and the supramolecular function of pyridyl moieties in one molecule. This unique feature provides pH-responsiveness and hydrogen/halogen/coordination binding sites in the same chromophore, paving a new way to prepare multi-functional responsive materials through non-covalent interactions and reversible chemical reactions. This review summarizes the photochemical and photophysical properties of azopyridine derivatives in supramolecular states (e.g., hydrogen/halogen bonding, coordination interactions, and quaternization reactions) and illustrates their applications from photoresponsive liquid crystals to light-driven devices. We hope this review can highlight azopyridine as one more versatile candidate molecule for designing novel photoresponsive materials towards light-driven applications. [ABSTRACT FROM AUTHOR]

Surface metrology plays a key role in many technological and scientific applications, such as manufacturing or material science, where optical methods are generally preferred since they are contactless, non-destructive and faster in comparison to their contact counterparts. In particular, interferometric methods usually perform spatial scanning and induce controlled phase delays using mechanical moving parts, which can cause instabilities on the system, therefore, affecting its performance. Here we put forward an alternative method in which we use a common-path interferometer and a liquid crystal spatial light modulator (SLM) to scan the sample and introduce phase delays, making the system completely digital. We first applied our approach to artificial samples with diverse topographies, and then to real samples with a sharp change in height, obtaining very good correlations between the measured and reference surfaces in both cases. We expect our work to be of interest to the optical metrology community, particularly those working on surface profilometry. [ABSTRACT FROM AUTHOR]

The article presents Aligned 2D carbon nanotube liquid crystals for wafer-scale electronics. Topics discussed include Semiconducting carbon nanotubes promise faster performance and lower power consumption than Si in field-effect transistors (FETs); and demonstrate that nanotubes collected at a liquid/liquid interface self-organize to form two-dimensional (2D) nematic liquid crystals that globally align with flow.

Mathematical studies of nematic liquid crystals address in general two rather different perspectives: that of fluid mechanics and that of calculus of variations. The former focuses on dynamical problems while the latter focuses on stationary ones. The two are usually studied with different mathematical tools and address different questions. The aim of this brief review is to give the practitioners in each area an introduction to some of the results and problems in the other area. Also, aiming to bridge the gap between the two communities, we will present a couple of research topics that generate natural connections between the two areas. This article is part of the theme issue 'Topics in mathematical design of complex materials'. [ABSTRACT FROM AUTHOR]

Development of photoliquefiable solid-state biomaterials at room temperature would address scientific challenges in life science. However, external stimuli-induced phase transitions are difficult for some biomacromolecules based materials, due to the high rigidity of these biomolecules. In this present work, by delicate molecule design on azobenzene-type ammonium surfactants, two new types of DNA-surfactant materials are fabricated. At room temperature, these DNA materials show photoliquefaction of ionic crystals to isotropic liquids under UV light, and fast self-assembly from isotropic liquids back to crystals after ceasing UV light, under the assistance of azobenzene isomerization. To achieve this objective, the designed solid-state DNA materials should have melting points near room temperature and an immediate liquid crystal to isotropic liquid transition process just above the melting points, which highly depends on the stoichiometric charge ratio between DNA and surfactants. As proved by the successful self-healing tests, these DNA ionic crystals are good biomaterials with potential applications in biomedicine and life science. This work would provide a new strategy for designing anhydrous functional biomaterials at room temperature by using rigid biomacromolecules. At room temperature, solid-state biomaterials with photoregulated crystal⇄isotropic liquid phase transition property are attractive functional materials in life science, considering the body temperature and living environment temperature of human beings. Although several kinds of anhydrous materials achieved isothermal photoresponsive phase transitions, the photoregulated phase transition of anhydrous biomacromolecules based materials has not been achieved at room temperature, due to the high rigidity of these biomolecules. In this work, by delicate molecule design on ammonium surfactants, we synthesized two kinds of anhydrous DNA-surfactants ionic crystals. These DNA materials show fast photoliquefaction under UV light and self-assembly after ceasing light, which affords excellent self-healing biomaterials. This work would provide a new strategy for designing anhydrous photoresponsive biomaterials by using rigid biomacromolecules. [Display omitted] [ABSTRACT FROM AUTHOR]

His talk, "Modelling Liquid Crystals and their Twisting" highlighted many of the new developments in this field. Prof. Gleeson's lecture "Out of the Box", highlighted the exciting developments and the latest applications of liquid crystal materials and provided an array of possible future directions aside from the normal LCD devices. The conference dinner was held at the conference venue after the poster sessions and after the dinner, Prof. Zannoni, together with Prof. Helen Gleeson and the conference organiser Prof. Susanne Klein (UWE) reviewed the development of the BLCS over recent years and presented a vision of the future for the younger generation of scientists. [Extracted from the article]

Designing and self-assembly of unconventional star-shaped mesogens or 'hekates' are of interest to materials science and molecular electronics. This work presents the synthesis of several symmetric trimeric liquid crystalline compounds comprising 1,3,5-trihydroxybenzene (phloroglucinol) as central core. The liquid crystalline behaviour was induced by attaching three rod-like azo-aromatic semi-flexible units to the central core via esteric linkages. Based on differential scanning calorimetry and polarising optical microscopy, the mesophase stability mainly depends on the alkyl chain length. The compounds showed monotropic or enantiotropic behaviour, except the compound with nine atoms on the chain end which is non-mesomorphic. In addition to the synthesis and mesophase characterisation, the self-assembled structures and individual properties have been characterised by molecular simulations. [ABSTRACT FROM AUTHOR]

The article focuses on chiral materials and examines the palette of morphologies that arises when micro droplets are deformed into non-spherical shapes in a controllable manner. It discusses the use of geometrical confinement and mechanical strain to manipulate orientational order, phase transitions, and topological defects that arise in chiral liquid crystal droplets.

Machine learning is a category of AI technology that is utilized in the product development cycle in numerous industries. It was reported that machine learning can be applied to predict the chemical properties of functional materials, for example, the self-assembly of surfactant solutions (Nanoscale, 2018, 10, 16013) and the chemical reactions of copper nanoparticles (ACS Energy Lett., 2018, 3, 2983). A liquid crystal (LC) molecule is a representative functional material. Monodisperse systems have been targeted in many theoretical studies; however, the resulting products usually have a polydisperse distribution. It has been reported in several studies that the properties exhibited by polydisperse systems are different from those observed in monodisperse systems. In this study, we focus on the physical properties of polydisperse systems i.e. the ratio of binary LC molecules on the phase transition temperature and the possibility of predicting the physical properties of the system using machine learning. A relatively high prediction accuracy was obtained using machine learning. This study demonstrates that machine learning can be utilized to predict the phase transition temperature of polydispersed LC systems. The results of this study will contribute to the further development of material science and molecular design via the application of machine learning. [ABSTRACT FROM AUTHOR]

We propose a method to confirm the biaxial phase in thermotropic nematic liquid crystals from measurement of the electro-optic characteristics. The electro-optic transmittance curve shows monotonic decrease to zero in the uniaxial phase but the curve shows a U-shaped behavior (or a monotonic decrease to nonzero transmittance) in the biaxial phase. In a bent-core mesogen 4,4′(1,3,4oxadiazole2,5diyl)dipheptylbenzoate (ODBP-Ph-C7), known to be in the nematic phase at temperatures between 173 and 222 °C, it has been found that its electro-optic curve at 190 °C shows a U-shaped behavior, while the curve at 210 °C shows a monotonic decrease to zero transmittance. We believe that these experimental results confirm the biaxial nature of ODBP-Ph-C7. [ABSTRACT FROM AUTHOR]

We studied the off-axis light transmission characteristics of the bright state of common liquid crystal device modes. The dark state of these device modes is optically compensated to have minimum light transmittance at all angles. Our research shows there is an unexpected universal shape of the off-axis light transmission value in its bright state, regardless of what liquid crystal mode is used. To understand this surprising fact, we consider simple dark and bright state models in terms of phase retardation and transmittance. [ABSTRACT FROM AUTHOR]

The dynamics of electro-optical switching processes in the biaxial nematic phase of an oxadizole-based bent-core liquid crystal (LC) was studied. This LC exhibits optical biaxiality in the lower temperature range of the nematic phase although it exhibits optical uniaxiality in the higher temperature range. In particular, the short axis and the long axis of the LC were independently switched when an electric field was applied in the biaxial nematic phase. The switching time of the short axis was much faster than that of the long axis in response to the applied field as well as in relaxation. [ABSTRACT FROM AUTHOR]

• Reactive LC monomers are a promising material for various applications in materials science. • LC monomers with smectic and nematic phases are useful for creating complex structures. • Methacrylic LCs esters with mono and enantiotropic behavior allows to engineer their corresponding polymers. • Using homologous series of reactive mesogens allows for the fine-tuning of the material's physical properties. The synthesis and phase characterization of a homologous series of 4′-alkyloxyphenyl 4-(6-(methacryloyloxy)hexyloxy))benzoate monomers have been carried out. The characterization comprises polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and temperature dependant small and wide-angle x-ray scattering (SAXS –WAXS). The X-ray data and POM images reveal both the nematic and monolayered orthogonal smectic A phase in M6En series. The monomers with a terminal chain length from five to twelve carbon atoms exhibit a wide temperature range of a stable smectic A phase with a narrow intervening nematic phase at higher temperatures. On cooling down from the isotropic phase the temperature range of the nematic and smectic A phase considerably increases. The specific features of the phase diagram and mesogenic properties of M6En series are discussed in terms of the peculiar molecular structure of these monomers. [ABSTRACT FROM AUTHOR]

Benzothiadiazole derivatives are widely investigated due to their well-known photophysical properties, including attractive liquid crystalline behavior. However, although their molecular cousin benzoxadiazole has similar characteristics, being a strong acceptor and good emitter, it has not been properly explored in materials science applications. In fact, no reports on its mesomorphic behavior could be found in the literature. Therefore, in this study a novel series of fluorescent calamitic liquid crystals derived from the 4,7-diphenyl-2,1,3-benzoxadiazole core, with varying numbers of alkoxy chains, were designed and successfully synthesized. All of the final compounds presented calamitic liquid crystal phases (nematic and smectic). Electrochemical studies showed oxidation and reduction patterns similar to those of benzochalcogendiazole analogs, however with higher band gaps. The compounds displayed yellow photoluminescence under UV light excitation in solution and in the solid state. In solution, the fluorescence quantum yields of the benzoxadiazole-based compounds were significantly higher than those previously described for similar benzothiadiazoles (ΦF = 0.38–0.45). [ABSTRACT FROM AUTHOR]

Confocal laser scanning microscopy is probably the most widely used and one of the most powerful techniques in basic biology, medicine and material sciences that is employed to elucidate the architecture of complex cellular structures and molecular macro-assemblies. It has recently been shown that the information content, signal-to-noise ratio and resolution of such microscopes (LSMs) can be improved significantly by adding different attachments or modifying their design, while retaining their user-friendly features and relatively moderate costs. Differential polarization (DP) attachments, using high-frequency modulation/demodulation circuits, have made LSMs capable of high-precision 2D and 3D mapping of the anisotropy of microscopic samples—without interfering with their 'conventional' fluorescence or transmission imaging (Steinbach et al. in Methods Appl Fluoresc 2:015005, 2014). The resolution and the quality of fluorescence imaging have been enhanced in the recently constructed Re-scan confocal microscopy (RCM) (De Luca et al. in Biomed Opt Express 4:2644–2656, 2013). In this work, we developed the RCM technique further, by adding a DP-attachment modulating the exciting laser beam via a liquid crystal (LC) retarder synchronized with the data acquisition system; by this means, and with the aid of a software, fluorescence-detected linear dichroism (FDLD), characteristic of the anisotropic molecular organization of the sample, could be recorded in parallel with the confocal fluorescence imaging. For demonstration, we show FDLD images of a plant cell wall (Ginkgo biloba) stained with Etzold's staining solution. [ABSTRACT FROM AUTHOR]

1-(acyl/aroyl)-3-(substituted)thioureas are exciting structures in the fields of organic synthesis, material sciences, and biomedical research. Of particular significance is the fact that acyl thiourea derivatives have been demonstrated to be highly exceptional ligands and their coordination compounds have extensively been investigated in the synthesis of pharmaceuticals and agrochemical ingredients. Moreover, these structural motifs are enjoying the prestigious status as versatile synthons in heterocyclic syntheses. Therefore, the progress to introduce functionalization on the backbone of 1-(acyl/aroyl)-3-(substituted)thioureas is highly desirable. This account summarizes our efforts to capture recent documented achievements by various research groups. [ABSTRACT FROM AUTHOR]

The rapid progress in material science and electronic technology is great possibility in designing reconfigurable wireless devices which are frequency tunable, flexible and consume low energy. In this paper, the anisotropic propriety of a new liquid crystal mixture 'GT3-23001ʹ in their nematic phase are exploited for designing tunable circular polarized cross slot patch antenna for WLAN applications. Reconfiguration of frequency response is controlled through an electrical external command. The proposed reconfigurable antenna based on liquid crystal satisfies a continuous frequency tuning of 15.83% with a global bandwidth of around 467.92 MHz (19.5%). to validate this novel mixture of liquid crystal, the simulated results are compared with the measured data and a good agreement is noticed. [ABSTRACT FROM AUTHOR]

Nonconjugated hydrocarbons, like bicyclo[1.1.1]pentane, bicyclo[2.2.2]octane, triptycene, and cubane are a unique class of rigid linkers. Due to their similarity in size and shape they are useful mimics of classic benzene moieties in drugs, so‐called bioisosteres. Moreover, they also fulfill an important role in material sciences as linear linkers, in order to arrange various functionalities in a defined spatial manner. In this Review article, recent developments and usages of these special, rectilinear systems are discussed. Furthermore, we focus on covalently linked, nonconjugated linear arrangements and discuss the physical and chemical properties and differences of individual linkers, as well as their application in material and medicinal sciences. Rigid, linear, versatile, and increasingly in use are attributes of nonconjugating hydrocarbons, such as bicyclo[1.1.1]pentane, bicyclo[2.2.2]octane, triptycene, and cubane. This Review article details their fundamental properties, synthetic chemistry, and use as linker systems in materials sciences and drug development (see figure). [ABSTRACT FROM AUTHOR]

A novel photonic composite film based on a luminescent dicyanodistyrylbenzene-based liquid crystal polymer network (LCN) was fabricated by using a silica colloidal crystal as a template. The upper part of inverse opal structure and the luminescence characteristics of dicyanodistyrylbenzene-based moiety endowed the resulting bilayer photonic film with structural color arising from coherent Bragg reflection and fluorescence properties, respectively. A fluorescence enhancement phenomenon was observed in the photonic film due to the overlap between the reflection band and emission band of the fluorescent LCN. More importantly, the photo-induced irreversible Z/E photoisomerization of dicyanodistyrylbenzene-based moiety in the photonic film led to both a reflection spectral shift and an observable fluorescence variation. On the basis of this effective phototuning process, microscopic patterning of photonic film was developed under both fluorescence mode and reflection mode. The work demonstrated here provides a new route to construct photo-responsive photonic film. [ABSTRACT FROM AUTHOR]

Abstract: Since the discovery of the liquid‐crystalline state in 1888, liquid crystal science has made great advances through fusion with various technologies and disciplines. Recently, new molecular design strategies and new self‐assembled structures have been developed as a result of the progress made in synthetic procedures and characterization techniques. Since these liquid crystals exhibit new functions and properties derived from their nanostructures and alignment, a variety of new functions for liquid crystals, such as transport for energy applications, separation for environmental applications, chromism, sensing, electrooptical effects, actuation, and templating have been proposed. This Review presents recent advances of liquid crystals that should contribute to the next generation of materials. [ABSTRACT FROM AUTHOR]