Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
6.6
5.0
Journals
Polymers
Special Issues
Polymer-Based Materials in Liquid Crystals
share announcement

Polymer-Based Materials in Liquid Crystals

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Applications".

Deadline for manuscript submissions: closed (31 January 2022) | Viewed by 22045

Special Issue Editors

Prof. Dr. Ko-Ting Cheng

E-Mail Website
Guest Editor
Department of Optics and Photonics, National Central University, Taoyuan 320317, Taiwan
Interests: physics and electro-optics of LCs; asymmetrical optics of LCs; polarization optics of LCs; green optics of LCs; LC devices
Special Issues, Collections and Topics in MDPI journals
Dr. Hsiu-Hui Chen

E-Mail Website
Guest Editor
Institute of Organic and Polymeric Materials, Research and Development Center of Smart Textile Technology, National Taipei University of Technology, Taipei 106, Taiwan
Interests: synthesis and application of discotic and polymerizeable LCs

Special Issue Information

Dear Colleagues,

Liquid crystals (LCs) possess specific anisotropic properties, including birefringence, dielectric anisotropy, magnetic anisotropy, and viscosity anisotropy. Several LC-based photonic applications, such as displays, lenses, polarization converters, biosensors, antennae, and smart windows, have been extensively developed in recent decades. In developing the above LC devices, polymer derivatives may play important roles to construct specific LC structures, such as polymer–network LCs, polymer–dispersed LCs, and polymer–stabilized LCs. The combination of polymer-based materials and LCs has attracted increasing attention in academia and in different industries. New conjugated LC materials with innovative design and semiconducting behavior that deviates from conventional polymer materials are gaining popularity. Highly conjugated polymer–network LC materials with covalent bonding or noncovalent bonding are viewed as new-generation materials in organic electronic devices because their self-assembling and self-healing properties allow structures to be built from molecular to macroscopic scales. “Smart materials” concepts have also been highly attractive in recent years. Some examples, having long-range crystalline ordering by complementary or guest–host interactions, including π–π interaction, hydrogen bonding, dipolar interactions, coordinative covalent bonding, and van der Waals forces, produce patterned self-assembly and form highly conjugated polymer–network LC materials.

The proposed Special Issue of Polymers, entitled “Polymer-Based Materials in Liquid Crystals,” aims to consolidate studies about polymers in LCs in the electro-optical and chemical fields. Topics for the Special Issue include but are not limited to the physics and chemistry of polymers in LCs, the applications and developments of LC devices with polymers, the syntheses of LC polymers, new types of highly ordered polymer-LC materials, and others.

Dr. Ko-Ting Cheng
Dr. Hsiu-Hui Chen
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • LCs
  • LC polymers
  • LC display/smart/lighting/sensing devices
  • highly conjugated LCs

Published Papers (9 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

13 pages, 26694 KiB  
Article
Vertical Alignment of Liquid Crystal on Sustainable 2,4-Di-tert-butylphenoxymethyl-Substituted Polystyrene Films
by DaEun Yang, Chowon Jin and Hyo Kang
Polymers 2022, 14(7), 1302; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14071302 - 23 Mar 2022
Viewed by 2239
Abstract
We synthesized sustainable 2,4-di-tert-butylphenoxymethyl-substituted polystyrenes (PDtBP#, # = 88, 68, 35, and 19, where # is molar percent contents of 2,4-di-tert-butylphenoxymethyl moiety), using post-polymerization modification reactions in order to study their liquid crystal (LC) alignment behaviors. In [...] Read more.
We synthesized sustainable 2,4-di-tert-butylphenoxymethyl-substituted polystyrenes (PDtBP#, # = 88, 68, 35, and 19, where # is molar percent contents of 2,4-di-tert-butylphenoxymethyl moiety), using post-polymerization modification reactions in order to study their liquid crystal (LC) alignment behaviors. In general, LC cells fabricated using polymer film with higher molar content of 2,4-di-tert-butylphenoxymethyl side groups showed vertical LC alignment behavior. LC alignment behavior in LC cell was related to the surface energy of the polymer alignment layer. For example, when the total surface energy value of the polymer layer was smaller than about 29.4 mJ/m2, vertical alignment behaviors were observed, generated by the nonpolar 2,4-di-tert-butylphenoxymethyl moiety with long and bulky carbon groups. Orientation stability was observed at 200 °C in the LC cells fabricated using PDtBP88 as the LC alignment layer. Therefore, as a natural compound modified polymer, PDtBP# can be used as a candidate LC alignment layer for environmentally friendly applications. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

12 pages, 3648 KiB  
Article
Photo-Embossed Surface Relief Structures with Improved Aspect Ratios and Their Applications in Liquid Crystal Devices
by Xiulan Yang, Minzhao Gu, Qunmei Wei, Yang Zhang, Sihan Wu, Qin Wu, Xiaowen Hu, Wei Zhao and Guofu Zhou
Polymers 2022, 14(1), 171; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14010171 - 02 Jan 2022
Cited by 1 | Viewed by 1625
Abstract
Photo-embossing has been developed as a convenient and economical method for creating complex surface relief structures in polymer films. The pursuit for large aspect ratios of the photo-embossed structures has never stopped. Here, we demonstrate a simple strategy to obtain improved aspect ratios [...] Read more.
Photo-embossing has been developed as a convenient and economical method for creating complex surface relief structures in polymer films. The pursuit for large aspect ratios of the photo-embossed structures has never stopped. Here, we demonstrate a simple strategy to obtain improved aspect ratios by adding a quick solvent developing step into the photo-embossing process. A good solvent for the monomer is used to remove unreacted monomers from the unexposed region, resulting in deepened valleys of the surface reliefs. In a polymer film as thin as 2.5 µm, the height of the surface reliefs can be increased by a factor of three to around 1.0 µm. This strategy is also shown to be compatible with other methods used to improve the aspect ratios of the photo-embossed structures. Lastly, we employ these surface relief structures in the fabrication of liquid crystal (LC) devices and investigate their performances for visible light regulation. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

13 pages, 5469 KiB  
Article
Low-Mass Liquid Crystalline Materials Blended in Recycled Thermoplastic Polyester Elastomer for Corrosion Inhibitor Application
by Chun-Jui Chen, Bo-Wei Huang, Po-Jung Tseng, Zhi-Yu Yang, Xiang Huang, Syang-Peng Rwei and Hsiu-Hui Chen
Polymers 2021, 13(18), 3188; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13183188 - 20 Sep 2021
Cited by 2 | Viewed by 2392
Abstract
In this work, the development and application of multicomponents obtained from recycled polyethylene terephthalate (r-PET) waste and monotropic liquid crystals as anticorrosion coatings are reported. The r-PET raw material was alcoholyzed and reproduced as a thermoplastic polyester elastomer (TPEE) with [...] Read more.
In this work, the development and application of multicomponents obtained from recycled polyethylene terephthalate (r-PET) waste and monotropic liquid crystals as anticorrosion coatings are reported. The r-PET raw material was alcoholyzed and reproduced as a thermoplastic polyester elastomer (TPEE) with different amounts (n%, n = 0, 1, 3, and 5) of 1,6-hexanediamine (HDA). Then, a fluorine-containing liquid crystal (4-cyano-3-fluorophenyl 4-ethylbenzoate (4CFE)) was incorporated into the TPEE mixture via solvent blending to modify and enhance the water resistance. The adhesion behavior of the coating on glass and iron substrates was evaluated by cross-cut tests and immersion tests in aqueous NaCl. In the corrosion resistance measurements, all of the coating samples fabricated with 10 ± 1 mm thickness were less active toward electrochemical corrosion (PEF% > 99%) than the bare iron plate, indicating that our work provided better protection against corrosion of the iron plate. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

13 pages, 3270 KiB  
Article
Effect of Position and Structure of the Terminal Moieties in the Side Group on the Liquid Crystal Alignment Behavior of Polystyrene Derivatives
by DaEun Yang, Kyutae Seo and Hyo Kang
Polymers 2021, 13(16), 2822; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13162822 - 22 Aug 2021
Viewed by 1928
Abstract
We synthesized a series of polystyrene derivatives containing various side groups, such as the 4-(tert-butyl)-phenoxymethyl, 3-(tert-butyl)-phenoxymethyl, 2-(tert-butyl)-phenoxymethyl, 4-cumyl-phenoxymethyl, and 4-trityl-phenoxymethyl groups, through a polymer modification reaction to examine the liquid crystal (LC) alignment of these derivatives. In [...] Read more.
We synthesized a series of polystyrene derivatives containing various side groups, such as the 4-(tert-butyl)-phenoxymethyl, 3-(tert-butyl)-phenoxymethyl, 2-(tert-butyl)-phenoxymethyl, 4-cumyl-phenoxymethyl, and 4-trityl-phenoxymethyl groups, through a polymer modification reaction to examine the liquid crystal (LC) alignment of these derivatives. In general, the vertical LC alignment on polymer films can be affected by the position and structure of the terminal moiety of the polymer side group. For example, the LC cells fabricated with 4-(tert-butyl)-phenoxymethyl-substituted polystyrene having a tert-butyl moiety as a para-type attachment to the phenoxy groups of the polystyrene derivatives exhibited vertical LC alignment, whereas the LC cells prepared from 3-(tert-butyl)- and 2-(tert-butyl)-phenoxymethyl-substituted polystyrene films exhibited planar LC alignment. In addition, the LC cells fabricated from 4-cumyl- and 4-trityl-phenoxymethyl-substituted polystyrene films with additional phenyl rings in the side groups exhibited planar LC alignment, in contrast to the LC alignment of the (tert-butyl)-phenoxymethyl-substituted polystyrene series. The vertical LC orientation was well correlated with the surface energy of these polymer films. For example, vertical LC orientation, which mainly originates due to the nonpolar tertiary carbon moiety having bulky groups, was observed when the surface energy of the polymer was lower than 36.6 mJ/m2. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

8 pages, 5676 KiB  
Article
A Planar Fresnel Lens in Reflection Type Based on Azo-Dye-Doped Cholesteric Liquid Crystals Fabricated by Photo-Alignment
by Bing-Yau Huang, Ting-Hui Chen, Tzu-Yeh Chen, Jia-De Lin, Tsung-Hsien Lin and Chie-Tong Kuo
Polymers 2020, 12(12), 2972; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12122972 - 12 Dec 2020
Cited by 3 | Viewed by 1805
Abstract
This paper presents a focusing efficiency and focal length tunable planar Fresnel lens in reflection type based on azo-dye-doped cholesterol liquid crystal film. The Fresnel-like pattern of a pumping beam can be formed by a Sagnac interferometer. When the azo-dye molecules are irradiated [...] Read more.
This paper presents a focusing efficiency and focal length tunable planar Fresnel lens in reflection type based on azo-dye-doped cholesterol liquid crystal film. The Fresnel-like pattern of a pumping beam can be formed by a Sagnac interferometer. When the azo-dye molecules are irradiated by the pumping beam, the photoalignment effect will be induced in the bright (odd) zones due to the trans–cis photoisomerization of azo-dye molecules. Thus, the structures of cholesteric liquid crystals in the odd zones will reorient from the imperfectly planar textures to the perfectly planar textures. The different structures of cholesteric liquid crystals in two adjacent zones will give rise to phase difference for the reflected light and thus function as a Fresnel lens. The focusing efficiency of the proposed Fresnel lens can be controlled by the applied voltages and affected by the polarization state of incident light. Moreover, various focal lengths of the Fresnel lens can be achieved by rewriting a different center radius of the Fresnel-like pattern. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

7 pages, 1908 KiB  
Article
Preferential Circularly Polarized Luminescence from a Nano-Segregated Liquid Crystalline Phase Using a Polymerized Twisted Nematic Platform
by Jae-Jin Lee and Suk-Won Choi
Polymers 2020, 12(11), 2529; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12112529 - 29 Oct 2020
Cited by 4 | Viewed by 1750
Abstract
In this study, a polymerized twisted nematic (TN) network was used as an extrinsic chiral platform to overcome the heterogeneity during spontaneous symmetry breaking in a mixed system comprising an achiral bent-core molecule and rod-like mesogen. The TN platform was prepared by photopolymerizing [...] Read more.
In this study, a polymerized twisted nematic (TN) network was used as an extrinsic chiral platform to overcome the heterogeneity during spontaneous symmetry breaking in a mixed system comprising an achiral bent-core molecule and rod-like mesogen. The TN platform was prepared by photopolymerizing a reactive mesogen dispersed in a low molecular weight liquid crystal with TN orientation. The use of TN orientation to correct the degeneracy in bent-core molecular systems has been previously reported; however, to the best of our knowledge, this is the first study that uses an extrinsic chiral platform of a polymerized TN network. The heterogeneity in the nano-segregated phase of the achiral mixture was suppressed using the extrinsic TN platform with a twisted angle θ of ≥ |±30°|. When an achiral mixture doped with a luminescent guest molecule was refilled into the extrinsic chiral platform, preferential deracemization with one-handedness occurred, corresponding to the handedness of the TN platform. Therefore, circularly polarized luminescence with a preferential handedness can be achieved using this extrinsic chiral platform. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

17 pages, 4766 KiB  
Article
High-Contrast and Scattering-Type Transflective Liquid Crystal Displays Based on Polymer-Network Liquid Crystals
by Cheng-Kai Liu, Wei-Hsuan Chen, Chung-Yu Li and Ko-Ting Cheng
Polymers 2020, 12(4), 739; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12040739 - 26 Mar 2020
Cited by 7 | Viewed by 2911
Abstract
The methods to enhance contrast ratios (CRs) in scattering-type transflective liquid crystal displays (ST-TRLCDs) based on polymer-network liquid crystal (PNLC) cells are investigated. Two configurations of ST-TRLCDs are studied and are compared with the common ST-TRLCDs. According to the comparisons, CRs are effectively [...] Read more.
The methods to enhance contrast ratios (CRs) in scattering-type transflective liquid crystal displays (ST-TRLCDs) based on polymer-network liquid crystal (PNLC) cells are investigated. Two configurations of ST-TRLCDs are studied and are compared with the common ST-TRLCDs. According to the comparisons, CRs are effectively enhanced by assembling a linear polarizer at the suitable position to achieve better dark states in the transmissive and reflective modes of the reported ST-TRLCDs with the optimized configuration, and its main trade-off is the loss of brightness in the reflective modes. The PNLC cell, which works as an electrically switchable polarizer herein, can be a PN-90° twisted nematic LC (PN-90° TNLC) cell or a homogeneous PNLC (H-PNLC) cell. The optoelectric properties of PN-90° TNLC and those of H-PNLC cells are compared in detail, and the results determine that the ST-TRLCD with the optimized configuration using an H-PNLC cell can achieve the highest CR. Moreover, no quarter-wave plate is used in the ST-TRLCD with the optimized configuration, so a parallax problem caused by QWPs can be solved. Other methods for enhancing the CRs of the ST-TRLCDs are also discussed. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

16 pages, 3956 KiB  
Article
Preparation and Characterization of Semi-Alicyclic Polyimide Resins and the Derived Alignment Layers for Liquid Crystal Display Technology
by Hong-sheng Bi, Xin-xin Zhi, Peng-hui Wu, Yan Zhang, Lin Wu, Yao-yao Tan, Yan-Jiang Jia, Jin-gang Liu and Xiu-min Zhang
Polymers 2020, 12(1), 217; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12010217 - 15 Jan 2020
Cited by 14 | Viewed by 3636
Abstract
Uniform alignment of rigid-rod liquid crystal (LC) molecules under applied voltage is critical for achievement of high-quality display for thin-film transistor-driven liquid crystal display devices (TFT-LCDs). The polymeric components that can induce the alignment of randomly aligned LC molecules are called alignment layers [...] Read more.
Uniform alignment of rigid-rod liquid crystal (LC) molecules under applied voltage is critical for achievement of high-quality display for thin-film transistor-driven liquid crystal display devices (TFT-LCDs). The polymeric components that can induce the alignment of randomly aligned LC molecules are called alignment layers (ALs). In the current work, a series of organo-soluble polyimide (SPI) ALs were designed and prepared from an alicyclic dianhydride, hydrogenated 3,3′,4,4′-biphenyltetracarboxylic dianhydride (HBPDA), and various aromatic diamines, including 4,4′-methylenedianiline (MDA) for SPI-1, 4,4′-aminodianiline (NDA) for SPI-2, 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenylmethane (TMMDA) for SPI-3, and 3,3′-diethyl-5,5′-dimethyl-4,4′-diaminodiphenylmethane (DMDEDA) for SPI-4. The derived SPI resins were all soluble in N-methyl-2-pyrrolidone (NMP). Four SPI alignment agents with the solid content of 6 wt.% were prepared by dissolving the SPI resins in the mixed solvent of NMP and butyl cellulose (BC) (NMP/BC = 80:20, weight ratio). Liquid crystal minicells were successfully fabricated using the developed SPI varnishes as the LC molecule alignment components. The SPI ALs showed good alignment ability for the LC molecules with the pretilt angles in the range of 1.58°–1.97°. The LC minicells exhibited good optoelectronic characteristics with voltage holding ratio (VHR) values higher than 96%. The good alignment ability of the SPI ALs is mainly attributed to the good comprehensive properties of the SPI layers, including high volume resistivity, high degree of imidization at the processing temperature (230 °C), good rubbing resistance, good thermal stability with glass transition temperatures (Tgs) higher than 260 °C, and excellent optical transparency with the transmittance higher than 97% at the wavelength of 550 nm. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Figure 1

7 pages, 2123 KiB  
Article
Electrically-Tunable Blue Phase Liquid Crystal Microlens Array Based on a Photoconductive Film
by Bing-Yau Huang, Shuan-Yu Huang, Chia-Hsien Chuang and Chie-Tong Kuo
Polymers 2020, 12(1), 65; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12010065 - 02 Jan 2020
Cited by 7 | Viewed by 2454
Abstract
This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive [...] Read more.
This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive mask resulting in the variation of conductivity is adopted to produce the gradient distribution of the electric field. The reorientations of liquid crystals according to the gradient distribution of the electric field induce the variation of the refractive index. Thus, the incident light experiences the gradient distribution of the refractive index and results in the focusing phenomenon. The study investigates the dependence of lens performance on UV exposure time, the focal length of the lens, and focusing intensities with various incident polarizations. The BPLC microlens array exhibits advantages such as electrically tunability, polarization independence, and fast response time. Full article
(This article belongs to the Special Issue Polymer-Based Materials in Liquid Crystals)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-9
Back to TopTop