LIQUID CRYSTALS
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2023
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IF 2.2
Yongxing Guo,Jinghua Zhao,Yi Li,Wei Liu,Yonggang Yang
Polymer-stabilised cholesteric liquid crystal (PSCLC) films attracted much attention in decoration and anti-counterfeiting. Herein, the PSCLC films were prepared using the mixtures of epoxy monomers through cationic photopolymerisation. The structural colour was tunable by changing the concentration of chiral dopant in the reaction mixture and polymerisation temperature. Due to polymerisation shrinkage, microcracks were formed at the surfaces of the PSCLC films, which originated from the oily streak defects of the CLC mixtures. Colourful patterns were prepared by controlling the polymerisation temperature. In addition, since light can leak out through the microcracks, the tetraphenylethylene-doped patterns can be applied in anti-counterfeiting.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2023
·
IF 2.2
Shuai-Yin Ma,Yuan-Sen Zhi,Hong-Shuang Zhang,Xiao-Zhi He,Bao-Yan Zhang,Fan-Bao Meng,Zhi-Na Ji
In this study, we have synthesised fluorescent liquid crystal polymers with good fluorescence and optical properties through effective molecular design. Firstly, two series of cholesteric liquid crystal polymers (PN and PS series) were prepared by graft copolymerisation of cholesteric monomer(N1), monomer containing cyanobiphenyls with different length of carbon-chain (N2 and N3) and monomer containing bromine (6-Br) with polymethylhydrosiloxane chain as the polymer backbone. Secondly, we obtained fluorescent polymers RPN and RPS series by etherification reaction of PN and PS series with fluorescent monomer (F). The molecular structures and mesomorphic behaviour of monomers and polymers were characterised by usual ways. All the polymers are confirmed to consist with molecular design. The fluorescence of the polymers was investigated by fluorescence spectroscopy and fluorescent images. The fluorescence intensity of polymers is highly dependent on temperature. Fluorescent cholesteric liquid crystal polymers emitted different intensity fluorescence under ultraviolet irradiation and some regularities were summarised. RPN series with short carbon-chain meets our expectations for performance with dual effects of fluorescence and selective reflection, which were well verified. The effect of monomers with different chain lengths on the properties of fluorescent polymers has been described.
研究领域:
材料科学
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化学
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产品关联
DOI
高影响因子
Nanomaterials
·
2017
·Vol. 7
·期 11
·376
·
IF 3.553
Yali Lin,Yujie Yang,Yuwei Shan,Lingli Gong,Jingzhi Chen,Sensen Li,Lujian Chen
Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidics. Water-soluble magnetofluid with Fe3O4nanoparticles incorporated in the inner aqueous core of CLC shells is responsible for the non-invasive transportable capability. With the aid of an external magnetic field, the reflection interactions between neighboring microshells and microdroplets were identified by varying the mutual distance in a group of magnetically transportable and unmovable spherical CLC structures. The temperature-dependent optical reflection patterns were investigated in close-packed hexagonal arrangements of seven CLC microdroplets and microshells with inverse helicity handedness. Moreover, we demonstrated that the magnetic field-assisted assembly of microshells array into geometric figures of uppercase English letters “L” and “C” was successfully achieved. We hope that these findings can provide good application prospects for security pattern designs.Keywords:magnetic nanoparticles;cholesteric liquid crystal;Bragg reflection;microfluidics
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULAR CRYSTALS AND LIQUID CRYSTALS
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2020
·
IF 0.512
Gege Jin,Yongmin Guo,Limin Wu,Yi Li,Baozong Li,Yonggang Yang
Three series of meta-perfluoroalkylphenol esters are synthesized. Both SmA and SmC phases are identified. Their clearing points increase with increasing the perfluorocarbon chain length, while decrease with increasing the alkoxy chain length. Comparison of the 3-tridecafluorohexylbenzoates and 3-tridecafluorohexylphenol esters, the 3-tridecafluorohexylbenzoates show higher clearing points, indicating that the direction of the ester bond plays an important role in the thermostability of the liquid crystalline phases. Moreover, it was proposed that the compounds with short and long alkoxy chains packed into different structures.
研究领域:
材料化学
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分子结构研究
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DOI
高影响因子
MATERIALS & DESIGN
·
2018
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IF 4.525
Mei Chen,Xiao Liang,Wei Hu,Lanying Zhang,Cuihong Zhang,Huai Yang
In this paper, we promote a new polymer microsphere-filled cholesteric-liquid crystal (PFLC) system sandwiched between two flexible substrates for making a robust composite film with both bistable optical performance and high mechanical strength . The effects of the size of the polymer microspheres (PMs) and the pitch of the cholesteric liquid crystals (ChLCs) on the electro-optical performance of the as-made PFLC films were systematically investigated. Results show that the optical appearance of the optimized PFLC film can be reversibly changed between transparent and light-scattering states according to electric field by switching the ChLCs between planar (P) and focal conic (FC) states. Moreover, both P and FC states are stable for more than one year after removing the electric field, which is due to the great reduced polymer specific surface area of 1.78 m 2 /g and the spatial hindrance from the in situ thermally polymerized PMs, respectively. Aside from the long-term optical stability, the high content of the densely packed PMs also endows the PFLC film with a satisfactory shearing strength of 206.0 kPa between the top and bottom substrates, showing great potential applications in a wide range of uses, such as smart windows , electronic paper or writing tablets.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
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2025
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IF 19
Jiaqi Huang,Guanfeng Gao,Xuebing Wen,Ming Yuan,Nan Hou,Yuyang Pu,Yifan Feng,Xiao-Fang Jiang,Xiaowen Hu,Guofu Zhou
Nonreciprocal devices, enabling asymmetric light transmission, are essential for many photonic applications. However, nonreciprocal devices driven by circularly polarized incident light, without relying on optical nonlinearity or magnetic fields, have been rarely reported. This study introduces a novel nonreciprocal device based on a photothermally driven cholesteric-to-isotropic phase transition (CIT) in cholesteric liquid crystals (CLCs). The device enables nonreciprocal transmission of circularly polarized light (CPL) without requiring external bias, magnetic fields, or optical nonlinearity. By incorporating a polydopamine (PDA)-doped polyvinyl acetate (PVA) layer for photothermal conversion, the device achieves self-biasing through heat generated by the incident signal light. The performance is tunable, with transmission contrast and insertion loss adjustable via the PDA concentration. At 808 nm CPL, the device achieves an isolation ratio of 7.7 dB and an insertion loss of 1.1 dB. Additionally, extending the photonic bandgap of the CLCs allows nonreciprocal performance at 405 nm CPL, with a high isolation ratio of 16.5 dB. The device also functions as an optical switch, enabling low-power signal light transmission with pump light assistance, and shows promise for applications in digital holography. These capabilities highlight the device's potential for use in all-optical communication networks and chirality-based photonic systems.
研究领域:
光学
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材料科学
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产品关联
DOI
高影响因子
OPTICS COMMUNICATIONS
·
2024
·
IF 2.2
Na Zhao,Xu Li,Yuzhou Chen,Dong Zhou,Yu Huang,Yongjun Liu
Liquid crystals (LCs) are commonly used to enhance the temperature sensitivity of fiber optic temperature sensors. Most studies utilized non-polymerizable LC-filled optical fibers, which suffer from drawbacks such as complex structure, low temperature detection capability, and narrow measurement range. In this study, a temperature sensor with a wide measurement range, high sensitivity, and simple fabrication process was proposed by directly integrating polymerizable cholesteric liquid crystal (CLC) films onto the end face of optical fibers. The effects of various components in CLC on temperature response were investigated and the temperature sensor fabricated from sample Ⅱ-4 exhibited the best performance. It can detect temperatures ranging from 30 to 270 °C. Within the range of 30–150 °C, its sensitivity is 381 pm/°C, while from 150 to 270 °C, the sensitivity increases to 879 pm/°C. Moreover, it achieves a rapid response time of just 300 ms. Its small size allows monitoring in confined spaces, expanding LC sensor applications.
研究领域:
材料科学
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光学工程
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
2024
·
IF 2.4
Zongqi Li,Jinghua Zhao,Liming Wu,Yi Li,Wei Liu,Yonggang Yang
Photorecording materials have been applied for information recording. Herein, a cinnamate liquid crystal with an enantiotropic nematic phase was synthesised, which can be isomerised and polymerised under the irradiation of the 365-nm UV light. Cholesteric liquid crystal polymer network (CLCN) films were prepared using the mixtures of it, LC242, a chiral dopant and a photoinitiator. The CLCN films possess a slight gradient helical pitch which increases from the bottom to the top of the films. The formation of this structure should be driven by the photoisomerisation of the cinnamate. Under the irradiation of 365-nm UV light with a low intensity, the CLC mixtures show a photochromic behaviour which is proposed to be driven by the formation of oligomers. Based on this, the CLC mixtures can be applied for optical recording.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 33
·22325-22335
·
IF 3.3
Huimin Zhang,Fei Li,Junqin Li,Zemin He,Jianjing Gao,Lifen Wen,Yuzhen Zhao,Zongcheng Miao
Bistable cholesteric liquid crystals have promising application prospects in various fields, such as smart windows and displays. However, the long-term stability of two individual states is not easy to achieve, hindering their practical use. In this research, the bistable feature was enhanced by constructing a microsphere-type polymer with a liquid-crystalline epoxy/thiol monomer in negative dielectric anisotropic cholesteric liquid crystals. Spectroscopic and optical examinations revealed that either the transparent planar state or the opaque focal conic state can be maintained without the aid of an external field. Moreover, they can be switched to each other by applying a high- or low-frequency electric field. Further, factors such as the chemical structure of thiol compounds, curing temperature and curing time were investigated to explore their influences on the micro morphology of the polymer and thereby the electro-optical properties. In addition, the frequency-dependent driving scheme was analysed. Finally, bistable switching was demonstrated using an optimized sample. This energy-efficient bistable film shines light on future applications in smart windows, photonic paper and other electro-optical devices.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DYES AND PIGMENTS
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2023
·
IF 4.5
Mengmeng Zhu,Ying Cao,Yuge Liang,Chao Ma,Hongbo Lu,Miao Xu,Longzhen Qiu,Jun Zhu
The transient planar (TP) state during the relaxation process, from homeotropic (H) to planar (P) state, of dye-doped cholesteric liquid crystals (DDCLCs) can be eliminated by adjusting the elastic constants, reducing the time and haze of the relaxation process. However, the elastic constants are easily influenced by temperature. Therefore, the operating temperature range for fast-relaxation DDCLCs is relatively narrow. This work demonstrates that a polymer helical template can be formed in the P state of DDCLCs by thiol-Michael addition polymerization . It can significantly expand the temperature range from 20 °C to 60 °C for fast-relaxation DDCLCs. More importantly, polymer-stabilized dye-doped cholesteric liquid crystals (PS-DDCLCs) did not show any reduction in the absorption of the dye or discoloration after polymerization. PS-DDCLCs could still achieve tri-state switching and could be used for fast-relaxation smart windows capable of adapting to increasing environmental temperatures. The proposed smart window can be used in vehicles and aircraft to prevent glare and protect privacy.
研究领域:
材料科学
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光学工程
✓ 已验证
DOI
高影响因子
Chemistry-An Asian Journal
·
2023
·Vol. 18
·期 19
·e202300636
·
IF 4.1
Jinghua Zhao,Runwei Yu,Limin Wu,Yi Li,Wei Liu,Yonggang Yang
Graphical Photochromic cholesteric liquid crystals (CLCs) were prepared, which could be applied for the preparation of colourful polymer-stabilized CLC (PSCLC) patterns. Based on handedness inversion, the obtained PSCLC patterns were suitably applied for anti-counterfeiting. Handedness inversion has been widely studied in supramolecular chemistry and material sciences. Herein, a photoisomerizable chiral dopant was synthesized, which could induce the formation of a cholesteric phase with right-handedness. The Bragg reflection band of the cholesteric liquid crystal (CLC) mixture shifted to the long wavelength with extending 365 nm UV light irradiation time. Based on this photochromic property, a colourful polymer-stabilized CLC (PSCLC) film was prepared using a grayscale mask. A handedness reversible CLC mixture was prepared using a mixture of this chiral dopant and S5011. With extending the UV light irradiation time, the handedness of the CLC mixture changed from right- to left-handedness. A patterned PSCLC film was prepared using this CLC mixture. Complementary images were observed under right- and left-handedness circularly polarized lights. The results shown here not only give us a better understanding the competition between photopolymerization and photoisomerization, but also lay the foundations for decoration and anti-counterfeiting.
研究领域:
材料科学
·
超分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LIQUID CRYSTALS
·
2023
·
IF 2.2
Runwei Yu,Jinghua Zhao,Limin Wu,Yi Li,Wei Liu,Yonggang Yang
Colourful polymer-stabilised cholesteric liquid crystal (PSCLC) film attracted much attention for their applications in decoration and anti-counterfeiting. Herein, a chiral dopant was synthesised using trans-p-hexoxycinnamic acid. With the addition of this chiral dopant in a reactive LC mixture, both thermochromic and photochromic phenomena were found. The Bragg reflection band of the CLC mixture shifted to long wavelength with extending 365-nm UV light irradiation time or increasing temperature. The structural colour can cover the visible range. The photochromic property of the CLC mixture was driven by the photoisomerisation of the chiral dopant. Colourful PSCLC patterns were prepared based on the thermochromic and/or photochromic properties and using masks. The results shown here not only give us a better understanding the competition between photopolymerisation and photoisomerisation, but also lay a foundation for the preparation of the decorations.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）