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Special Issue "Liquid Crystals"

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A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (28 February 2014)

Special Issue Editors

Guest Editor
Dr. João Luis Maia Figueirinhas (Website)

CFMC-UL, Av. Prof. Gama Pinto 2, 1649-003 Lisboa, Portugal, and Departamento de Física, IST-TU-Lisbon, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
Guest Editor
Dr. Ingo Dierking (Website)

The University of Manchester, Oxford Road, Manchester, UK
Interests: liquid crystals; chiral liquid crystals; ferroelectric liquid crystals; polymer stabilized liquid crystals; nanoparticles in anisotropic fluids; liquid crystal-nanotube dispersions; defects and defect dynamics; phase ordering in soft matter; fractal structures
Guest Editor
Dr. Maria Helena Figueiredo Godinho (Website)

CENIMAT - CENTRO DE INVESTIGAÇÃO EM MATERIAIS, Faculdade de Ciências e Tecnologia - Universidade Nova de Lisboa Campus da Caparica, 2829 - 516 Caparica, Portugal

Special Issue Information

Dear Colleagues,

Liquid crystals can be found in both synthetic and natural materials, which include DNA, cellulose, soaps, and cholesteryl esters. Liquid crystal basic concepts are an inspiration for various branches of physics, chemistry, materials science, mathematics, biology, and engineering. These concepts enable the synthesis and characterization of new materials with low-molecular weight, as well as of polymeric and elastomeric materials. Fundamental theories and models of liquid crystals have gained great importance in many scientific communities. The concepts of orientational order and cooperative molecular behavior have entered the actual basic knowledge of the bio-sciences community, and have contributed to the understanding of muscle function, cell division and membranes, and morphogenesis.

Recent trends in liquid crystal research include topics such as polymer-modified anisotropic fluids, dispersions of liquid crystals with various nano-sized particles, topological defects in soft materials, new lyotropic systems, liquid crystal functionality in living systems, and the synthesis of liquid crystal based functional materials (e.g., photonic materials, organic plastic conductors, semiconductors, materials in sensors, materials used in switchable GHz applications, and materials for data storage), along with the study of these materials’ properties and applications.

For this special issue, we invite authors to contribute research articles or reviews on the broad range of topics addressed above.

Dr. João Luis Maia Figueirinhas
Dr. Ingo Dierking
Dr. Maria Helena Figueiredo Godinho
Guest Editors

 

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Keywords

  • liquid crystals
  • anisotropic Fluids
  • self-Organization
  • thermotropic and Lyotropic systems
  • polymers, Nanoparticles
  • functional Materials
  • biological and Living Systems
  • photonics
  • organic Conductors
  • sensors
  • simulations of Soft Matter
  • topological Defects

Published Papers (18 papers)

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Research

Jump to: Review

Open AccessArticle Liquid Crystalline Network Composites Reinforced by Silica Nanoparticles
Materials 2014, 7(7), 5356-5365; doi:10.3390/ma7075356
Received: 11 March 2014 / Revised: 4 June 2014 / Accepted: 6 June 2014 / Published: 22 July 2014
Cited by 1 | PDF Full-text (1031 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Liquid crystalline networks (LCNs) are a class of polymers, which are able to produce mechanical actuation in response to external stimuli. Recent creation of LCNs with exchangeable links (xLCNs) makes LCNs easy moldable. As the xLCNs need to be shaped at a [...] Read more.
Liquid crystalline networks (LCNs) are a class of polymers, which are able to produce mechanical actuation in response to external stimuli. Recent creation of LCNs with exchangeable links (xLCNs) makes LCNs easy moldable. As the xLCNs need to be shaped at a high temperature, it is important to enhance their thermal and mechanical properties. In this paper, a series of xLCNs/SiO2 composites containing 1%–7% SiO2 nanoparitcles (SNP) were prepared and their thermal and mechanical properties were examined. The results show that xLCNs/SNP composites have lower liquid crystalline-isotropic phase transition temperature and higher decomposition temperature than pure LCN. The tensile strength and the elongation at break of xLCNs at high temperatures were also enhanced due to the addition of SNPs. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Improving the Pass-Band Return Loss in Liquid Crystal Dual-Mode Bandpass Filters by Microstrip Patch Reshaping
Materials 2014, 7(6), 4524-4535; doi:10.3390/ma7064524
Received: 28 February 2014 / Revised: 1 April 2014 / Accepted: 3 June 2014 / Published: 13 June 2014
PDF Full-text (998 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, the design and experimental characterization of a tunable microstrip bandpass filter based on liquid crystal technology are presented. A reshaped microstrip dual-mode filter structure has been used in order to improve the device performance. Specifically, the aim is to [...] Read more.
In this paper, the design and experimental characterization of a tunable microstrip bandpass filter based on liquid crystal technology are presented. A reshaped microstrip dual-mode filter structure has been used in order to improve the device performance. Specifically, the aim is to increase the pass-band return loss of the filter by narrowing the filter bandwidth. Simulations confirm the improvement of using this new structure, achieving a pass-band return loss increase of 1.5 dB at least. Because of the anisotropic properties of LC molecules, a filter central frequency shift from 4.688 GHz to 5.045 GHz, which means a relative tuning range of 7.3%, is measured when an external AC voltage from 0 Vrms to 15 Vrms is applied to the device. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Janus Nematic Colloids with Designable Valence
Materials 2014, 7(6), 4272-4281; doi:10.3390/ma7064272
Received: 3 April 2014 / Revised: 21 May 2014 / Accepted: 23 May 2014 / Published: 30 May 2014
Cited by 5 | PDF Full-text (1136 KB) | HTML Full-text | XML Full-text
Abstract
Generalized Janus nematic colloids based on various morphologies of particle surface patches imposing homeotropic and planar surface anchoring are demonstrated. By using mesoscopic numerical modeling, multiple types of Janus particles are explored, demonstrating a variety of novel complex colloidal structures. We also [...] Read more.
Generalized Janus nematic colloids based on various morphologies of particle surface patches imposing homeotropic and planar surface anchoring are demonstrated. By using mesoscopic numerical modeling, multiple types of Janus particles are explored, demonstrating a variety of novel complex colloidal structures. We also show binding of Janus particles to a fixed Janus post in the nematic cell, which acts as a seed and a micro-anchor for the colloidal structure. Janus colloidal structures reveal diverse topological defect configurations, which are effectively combinations of surface boojum and bulk defects. Topological analysis is applied to defects, importantly showing that topological charge is not a well determined topological invariant in such patchy nematic Janus colloids. Finally, this work demonstrates colloidal structures with designable valence, which could allow for targeted and valence-conditioned self-assembly at micro- and nano-scale. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle New Lyotropic Mixtures with Non-Chiral N-Acylamino Acid Surfactants Presenting the Biaxial Nematic Phase Investigated by Laser Conoscopy, Polarized Optical Microscopy and X-ray Diffraction
Materials 2014, 7(6), 4132-4147; doi:10.3390/ma7064132
Received: 8 March 2014 / Revised: 22 April 2014 / Accepted: 21 May 2014 / Published: 27 May 2014
Cited by 2 | PDF Full-text (1104 KB) | HTML Full-text | XML Full-text
Abstract
Amino acid-based surfactants were used as the main surfactants to prepare new lyotropic mixtures presenting three nematic phases. One of them is biaxial (NB), and the two others are uniaxial, discotic (ND) and calamitic (N [...] Read more.
Amino acid-based surfactants were used as the main surfactants to prepare new lyotropic mixtures presenting three nematic phases. One of them is biaxial (NB), and the two others are uniaxial, discotic (ND) and calamitic (NC). These surfactants were the non-chiral molecules, potassium N-dodecanoyl-DL-alaninate (DL-KDDA), potassium N-dodecanoyl-DL-serinate (DL-KDDS), disodium N-dodecanoyl-DL-aspartate (DL-NaDDAs) and potassium N-dodecanoyl-glycinate (KDDGly). Measurements of the optical birefringences and X-ray diffraction analysis were used to characterize the nematic phases and phase transitions. Mixtures with DL-KDDS exhibited the largest biaxial phase domain (~9 °C) with respect to the other mixtures in this study. The results obtained with the KDDGly mixture showed that the existence of hydrogen bonding between the head groups of the surfactant molecules seems to hinder the orientation of the micelles under the action of an external magnetic field. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Novel Discotic Boroxines: Synthesis and Mesomorphic Properties
Materials 2014, 7(5), 4045-4056; doi:10.3390/ma7054045
Received: 8 April 2014 / Revised: 7 May 2014 / Accepted: 8 May 2014 / Published: 22 May 2014
Cited by 4 | PDF Full-text (816 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A new synthetic approach to highly substituted triphenylboroxines 11 is described. Their mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (SAXS, WAXS). The tris(3,4,5-trialkyloxy)phenyl functionalized derivatives 11be showed broad mesophases for a [...] Read more.
A new synthetic approach to highly substituted triphenylboroxines 11 is described. Their mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (SAXS, WAXS). The tris(3,4,5-trialkyloxy)phenyl functionalized derivatives 11be showed broad mesophases for a minimum alkyl chain length of C9. The phase widths ranged from 110 K to 77 K near room temperature, thus decreasing with enhanced alkyl chain lengths. Textures observed under POM indicated a columnar hexagonal (Colh) mesophase symmetry that was confirmed by X-ray diffraction experiments. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Figures

Open AccessArticle Optical Properties of Electrically Tunable Two-Dimensional Photonic Lattice Structures Formed in a Holographic Polymer-Dispersed Liquid Crystal Film: Analysis and Experiment
Materials 2014, 7(5), 3677-3698; doi:10.3390/ma7053677
Received: 11 March 2014 / Revised: 7 April 2014 / Accepted: 21 April 2014 / Published: 7 May 2014
Cited by 3 | PDF Full-text (16266 KB) | HTML Full-text | XML Full-text
Abstract
We report on theoretical and experimental investigations of optical wave propagations in two-dimensional photonic lattice structures formed in a holographic polymer-dispersed liquid crystal (HPDLC) film. In the theoretical analysis we employed the 2×2 matrix formulation and the statistical thermodynamics model to analyze [...] Read more.
We report on theoretical and experimental investigations of optical wave propagations in two-dimensional photonic lattice structures formed in a holographic polymer-dispersed liquid crystal (HPDLC) film. In the theoretical analysis we employed the 2×2 matrix formulation and the statistical thermodynamics model to analyze the formation of anisotropic photonic lattice structures by holographic polymerization. The influence of multiple reflections inside an HPDLC film on the formed refractive index distribution was taken into account in the analysis. In the experiment we fabricated two-dimensional photonic lattice structures in an HPDLC film under three-beam interference holographic polymerization and performed optical measurements of spectral transmittances and wavelength dispersion. We also demonstrated the electrical control capability of the fabricated photonic lattice structure and its dependence on incident wave polarization. These measured results were compared with the calculated ones by means of photonic band and beam propagation calculations. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Figures

Open AccessArticle Frequency and Temperature Dependence of Fabrication Parameters in Polymer Dispersed Liquid Crystal Devices
Materials 2014, 7(5), 3512-3521; doi:10.3390/ma7053512
Received: 15 February 2014 / Revised: 9 April 2014 / Accepted: 28 April 2014 / Published: 2 May 2014
Cited by 2 | PDF Full-text (600 KB) | HTML Full-text | XML Full-text
Abstract
A series of polymer dispersed liquid crystal devices using glass substrates have been fabricated and investigated focusing on their electrical properties. The devices have been studied in terms of impedance as a function of frequency. An electric equivalent circuit has been proposed, [...] Read more.
A series of polymer dispersed liquid crystal devices using glass substrates have been fabricated and investigated focusing on their electrical properties. The devices have been studied in terms of impedance as a function of frequency. An electric equivalent circuit has been proposed, including the influence of the temperature on the elements into it. In addition, a relevant effect of temperature on electrical measurements has been observed. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Physics of Free-Standing Lyotropic Films
Materials 2014, 7(5), 3453-3469; doi:10.3390/ma7053453
Received: 17 March 2014 / Revised: 24 April 2014 / Accepted: 28 April 2014 / Published: 30 April 2014
PDF Full-text (53782 KB) | HTML Full-text | XML Full-text
Abstract We explore the structures and properties of stable, free-standing films of lyotropic mesophases drawn on apertures of various shapes in an atmosphere of controlled humidity. New phenomena are uncovered and interpreted. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Figures

Open AccessArticle The Design and Investigation of Nanocomposites Containing Dimeric Nematogens and Liquid Crystal Gold Nanoparticles with Plasmonic Properties Showing a Nematic-Nematic Phase Transition (Nu-Nx/Ntb)
Materials 2014, 7(5), 3494-3511; doi:10.3390/ma7053494
Received: 12 March 2014 / Revised: 11 April 2014 / Accepted: 17 April 2014 / Published: 30 April 2014
Cited by 2 | PDF Full-text (2334 KB) | HTML Full-text | XML Full-text
Abstract
The construction of liquid crystal compositions consisting of the dimeric liquid crystal, CB_C9_CB (cyanobiphenyl dimer = 1'',9''-bis(4-cyanobiphenyl-4'-yl)nonane), and the range of nematic systems is explored. The materials include a laterally functionalized monomer, which was used to construct a phase diagram with CB_C9_CB [...] Read more.
The construction of liquid crystal compositions consisting of the dimeric liquid crystal, CB_C9_CB (cyanobiphenyl dimer = 1'',9''-bis(4-cyanobiphenyl-4'-yl)nonane), and the range of nematic systems is explored. The materials include a laterally functionalized monomer, which was used to construct a phase diagram with CB_C9_CB, as well as one laterally linked dimer liquid crystal material and two liquid crystal gold nanoparticle (LC-Au-NPs) systems. For the Au-NP-LCs, the NP diameters were varied between ~3.3 nm and 10 nm. Stable mixtures that exhibit a nematic-nematic phase transition are reported and were investigated by POM (polarizing optical microscopy), DSC (differential scanning calorimetry) and X-ray diffraction studies. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Preparation of Nanocomposite Plasmonic Films Made from Cellulose Nanocrystals or Mesoporous Silica Decorated with Unidirectionally Aligned Gold Nanorods
Materials 2014, 7(4), 3021-3033; doi:10.3390/ma7043021
Received: 1 March 2014 / Revised: 24 March 2014 / Accepted: 26 March 2014 / Published: 11 April 2014
Cited by 10 | PDF Full-text (791 KB) | HTML Full-text | XML Full-text
Abstract
Using liquid crystalline self-assembly of cellulose nanocrystals, we achieve long-range alignment of anisotropic metal nanoparticles in colloidal nanocrystal dispersions that are then used to deposit thin structured films with ordering features highly dependent on the deposition method. These hybrid films are comprised [...] Read more.
Using liquid crystalline self-assembly of cellulose nanocrystals, we achieve long-range alignment of anisotropic metal nanoparticles in colloidal nanocrystal dispersions that are then used to deposit thin structured films with ordering features highly dependent on the deposition method. These hybrid films are comprised of gold nanorods unidirectionally aligned in a matrix that can be made of ordered cellulose nanocrystals or silica nanostructures obtained by using cellulose-based nanostructures as a replica. The ensuing long-range alignment of gold nanorods in both cellulose-based and nanoporous silica films results in a polarization-sensitive surface plasmon resonance. The demonstrated device-scale bulk nanoparticle alignment may enable engineering of new material properties arising from combining the orientational ordering of host nanostructures and properties of the anisotropic plasmonic metal nanoparticles. Our approach may also allow for scalable fabrication of plasmonic polarizers and nanoporous silica structures with orientationally ordered anisotropic plasmonic nanoinclusions. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Liquid Crystal Lensacons, Logarithmic and Linear Axicons
Materials 2014, 7(4), 2593-2604; doi:10.3390/ma7042593
Received: 21 February 2014 / Revised: 12 March 2014 / Accepted: 24 March 2014 / Published: 28 March 2014
PDF Full-text (1210 KB) | HTML Full-text | XML Full-text
Abstract
Until now, several attempts have been made to obtain axicons by using liquid crystals. Previous results had always a considerable deviation from the linear response and the resulting aperture is square. In addition, classical fabrications methods are expensive and only produce fixed [...] Read more.
Until now, several attempts have been made to obtain axicons by using liquid crystals. Previous results had always a considerable deviation from the linear response and the resulting aperture is square. In addition, classical fabrications methods are expensive and only produce fixed phase profiles. In this study, a novel structure to obtain tunable axicons with a perfect conical shape and a circular aperture is proposed and theoretically studied. The proposed optical device is based on nematic liquid crystal and phase shifted electrical signals. A simulation program consisted of Finite Elements Method to solve the voltage distribution combined with the Frank-Oseen equation to solve the molecular position of the nematic liquid crystal is employed. This device is totally reconfigurable by using low voltage signals. The focus depth and the position of this one can be controlled electrically. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Passive Temperature Stabilization of Silicon Photonic Devices Using Liquid Crystals
Materials 2014, 7(3), 2229-2241; doi:10.3390/ma7032229
Received: 7 February 2014 / Revised: 1 March 2014 / Accepted: 6 March 2014 / Published: 14 March 2014
Cited by 7 | PDF Full-text (779 KB) | HTML Full-text | XML Full-text
Abstract
In this work we explore the negative thermo-optic properties of liquid crystal claddings for passive temperature stabilization of silicon photonic integrated circuits. Photonic circuits are playing an increasing role in communications and computing, but they suffer from temperature dependent performance variation. Most [...] Read more.
In this work we explore the negative thermo-optic properties of liquid crystal claddings for passive temperature stabilization of silicon photonic integrated circuits. Photonic circuits are playing an increasing role in communications and computing, but they suffer from temperature dependent performance variation. Most existing techniques aimed at compensation of thermal effects rely on power hungry Joule heating. We show that integrating a liquid crystal cladding helps to minimize the effects of a temperature dependent drift. The advantage of liquid crystals lies in their high negative thermo-optic coefficients in addition to low absorption at the infrared wavelengths. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessArticle Dispersion of γ-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects
Materials 2014, 7(3), 1502-1519; doi:10.3390/ma7031502
Received: 16 January 2014 / Revised: 5 February 2014 / Accepted: 12 February 2014 / Published: 27 February 2014
Cited by 2 | PDF Full-text (879 KB) | HTML Full-text | XML Full-text
Abstract
We report an experimental study on confined systems formed by butyloxybenzylidene octylaniline liquid crystal (4O.8) + γ-alumina nanoparticles. The effects of the confinement in the thermal and dielectric properties of the liquid crystal under different densities of nanoparticles is analyzed by means [...] Read more.
We report an experimental study on confined systems formed by butyloxybenzylidene octylaniline liquid crystal (4O.8) + γ-alumina nanoparticles. The effects of the confinement in the thermal and dielectric properties of the liquid crystal under different densities of nanoparticles is analyzed by means of high resolution Modulated Differential Scanning Calorimetry (MDSC) and broadband dielectric spectroscopy. First, a drastic depression of the N-I and SmA-N transition temperatures is observed with confinement, the more concentration of nanoparticles the deeper this depression is, driving the nematic range closer to the room temperature. An interesting experimental law is found for both transition temperatures. Second, the change in shape of the heat capacity peaks is quantified by means of the full width half maximum (FWHM). Third, the confinement does not noticeably affect the molecular dynamics. Finally, the combination of nanoparticles and the external applied electric field tends to favor the alignment of the molecules in metallic cells. All these results indicate that the confinement of liquid crystals by means of γ-alumina nanoparticles could be optimum for liquid crystal-based electrooptic devices. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
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Review

Jump to: Research

Open AccessReview Structural Rheology of the Smectic Phase
Materials 2014, 7(7), 5146-5168; doi:10.3390/ma7075146
Received: 1 April 2014 / Revised: 13 June 2014 / Accepted: 24 June 2014 / Published: 16 July 2014
Cited by 2 | PDF Full-text (6487 KB) | HTML Full-text | XML Full-text
Abstract
In this review article, we discuss the rheological properties of the thermotropic smectic liquid crystal 8CB with focal conic domains (FCDs) from the viewpoint of structural rheology. It is known that the unbinding of the dislocation loops in the smectic phase drives [...] Read more.
In this review article, we discuss the rheological properties of the thermotropic smectic liquid crystal 8CB with focal conic domains (FCDs) from the viewpoint of structural rheology. It is known that the unbinding of the dislocation loops in the smectic phase drives the smectic-nematic transition. Here we discuss how the unbinding of the dislocation loops affects the evolution of the FCD size, linear and nonlinear rheological behaviors of the smectic phase. By studying the FCD formation from the perpendicularly oriented smectic layers, we also argue that dislocations play a key role in the structural development in layered systems. Furthermore, similarities in the rheological behavior between the FCDs in the smectic phase and the onion structures in the lyotropic lamellar phase suggest that these systems share a common physical origin for the elasticity. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessReview From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials
Materials 2014, 7(6), 4601-4627; doi:10.3390/ma7064601
Received: 30 March 2014 / Revised: 26 May 2014 / Accepted: 10 June 2014 / Published: 18 June 2014
Cited by 2 | PDF Full-text (1592 KB) | HTML Full-text | XML Full-text
Abstract
Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the [...] Read more.
Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR), Rheology coupled with NMR (Rheo-NMR), rheology, optical methods, Magnetic Resonance Imaging (MRI), Wide Angle X-rays Scattering (WAXS), were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessReview A Review of Polymer-Stabilized Ferroelectric Liquid Crystals
Materials 2014, 7(5), 3568-3587; doi:10.3390/ma7053568
Received: 9 March 2014 / Revised: 13 April 2014 / Accepted: 28 April 2014 / Published: 6 May 2014
Cited by 6 | PDF Full-text (2459 KB) | HTML Full-text | XML Full-text
Abstract
The polymer stabilized state of ferroelectric liquid crystals (FLC) is reviewed; and the effect of a dispersed polymer network in an FLC outlined and discussed. All fundamental material aspects are demonstrated; such as director tilt angle; spontaneous polarization; response time and viscosity; [...] Read more.
The polymer stabilized state of ferroelectric liquid crystals (FLC) is reviewed; and the effect of a dispersed polymer network in an FLC outlined and discussed. All fundamental material aspects are demonstrated; such as director tilt angle; spontaneous polarization; response time and viscosity; as well as the dielectric modes. It was found that the data can largely be explained by assuming an elastic interaction between the polymer network strands and the liquid crystal molecules. The elastic interaction parameter was determined; and increases linearly with increasing polymer concentration. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessReview Emerging Applications of Liquid Crystals Based on Nanotechnology
Materials 2014, 7(3), 2044-2061; doi:10.3390/ma7032044
Received: 27 January 2014 / Revised: 25 February 2014 / Accepted: 28 February 2014 / Published: 11 March 2014
Cited by 2 | PDF Full-text (912 KB) | HTML Full-text | XML Full-text
Abstract
Diverse functionalities of liquid crystals (LCs) offer enormous opportunities for their potential use in advanced mobile and smart displays, as well as novel non-display applications. Here, we present snapshots of the research carried out on emerging applications of LCs ranging from electronics [...] Read more.
Diverse functionalities of liquid crystals (LCs) offer enormous opportunities for their potential use in advanced mobile and smart displays, as well as novel non-display applications. Here, we present snapshots of the research carried out on emerging applications of LCs ranging from electronics to holography and self-powered systems. In addition, we will show our recent results focused on the development of new LC applications, such as programmable transistors, a transparent and active-type two-dimensional optical array and self-powered display systems based on LCs, and will briefly discuss their novel concepts and basic operating principles. Our research will give insights not only into comprehensively understanding technical and scientific applications of LCs, but also developing new discoveries of other LC-based devices. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available
Open AccessReview Liquid-Crystal-Enabled Active Plasmonics: A Review
Materials 2014, 7(2), 1296-1317; doi:10.3390/ma7021296
Received: 17 January 2014 / Revised: 1 February 2014 / Accepted: 12 February 2014 / Published: 18 February 2014
Cited by 35 | PDF Full-text (1303 KB) | HTML Full-text | XML Full-text
Abstract
Liquid crystals are a promising candidate for development of active plasmonics due to their large birefringence, low driving threshold, and versatile driving methods. We review recent progress on the interdisciplinary research field of liquid crystal based plasmonics. The research scope of this [...] Read more.
Liquid crystals are a promising candidate for development of active plasmonics due to their large birefringence, low driving threshold, and versatile driving methods. We review recent progress on the interdisciplinary research field of liquid crystal based plasmonics. The research scope of this field is to build the next generation of reconfigurable plasmonic devices by combining liquid crystals with plasmonic nanostructures. Various active plasmonic devices, such as switches, modulators, color filters, absorbers, have been demonstrated. This review is structured to cover active plasmonic devices from two aspects: functionalities and driven methods. We hope this review would provide basic knowledge for a new researcher to get familiar with the field, and serve as a reference for experienced researchers to keep up the current research trends. Full article
(This article belongs to the Special Issue Liquid Crystals) Print Edition available

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