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Saeed MH, Zhang S, Cao Y, Zhou L, Hu J, Muhammad I, Xiao J, Zhang L, Yang H. Recent Advances in The Polymer Dispersed Liquid Crystal Composite and Its Applications. Molecules 2020; 25:E5510. [PMID: 33255525 PMCID: PMC7727789 DOI: 10.3390/molecules25235510] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/16/2022] Open
Abstract
Polymer dispersed liquid crystals (PDLCs) have kindled a spark of interest because of their unique characteristic of electrically controlled switching. However, some issues including high operating voltage, low contrast ratio and poor mechanical properties are hindering their practical applications. To overcome these drawbacks, some measures were taken such as molecular structure optimization of the monomers and liquid crystals, modification of PDLC and doping of nanoparticles and dyes. This review aims at detailing the recent advances in the process, preparations and applications of PDLCs over the past six years.
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Affiliation(s)
- Mohsin Hassan Saeed
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China; (M.H.S.); (Y.C.); (L.Z.); (I.M.)
| | - Shuaifeng Zhang
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (S.Z.); (J.H.)
| | - Yaping Cao
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China; (M.H.S.); (Y.C.); (L.Z.); (I.M.)
| | - Le Zhou
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China; (M.H.S.); (Y.C.); (L.Z.); (I.M.)
| | - Junmei Hu
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (S.Z.); (J.H.)
| | - Imran Muhammad
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China; (M.H.S.); (Y.C.); (L.Z.); (I.M.)
| | - Jiumei Xiao
- Department of Applied Mechanics, University of Sciences and Technology Beijing, Beijing 100083, China;
| | - Lanying Zhang
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China; (M.H.S.); (Y.C.); (L.Z.); (I.M.)
| | - Huai Yang
- Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China; (M.H.S.); (Y.C.); (L.Z.); (I.M.)
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Zhao Y, Li S, Zhang D, Zhao Y, Ye Y, Li Z, Li Z. Improved TDM scheme and data extracting algorithm for polymerization evaluation. OPTICS EXPRESS 2020; 28:17979-17987. [PMID: 32679999 DOI: 10.1364/oe.394199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
To quickly evaluate holographic photopolymers with different formulations, the most effective method is to record a volume holographic grating in the samples and detect the grating's diffraction in real time. Since the volume grating is highly sensitive to incident angle, existing schemes need to precisely control many space-related parameters. This study proposes an improved scheme, in which two different sized spots are used to reduce the requirements for the overlap of the two spots and the installation precision of the samples. Transmittances, diffractive efficiencies and diffractive asymmetries are obtained at a high sampling rate, through a specifically designed algorithm with the data from uncalibrated high-speed photodiodes. The experimental results show that the proposed scheme performance well in evaluating holographic photopolymer.
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Ma J, Wu T, Cui Y, Li J, Wang J, Su P. Modified monomer diffusion model for volume holographic grating formation in photopolymers. APPLIED OPTICS 2020; 59:3952-3958. [PMID: 32400666 DOI: 10.1364/ao.388633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Monomer diffusion models are important in describing the formation mechanism of the volume holographic grating in photopolymers. The most representative of these models is the first-order diffusion model, which neglects the influence of the exposure intensity threshold and dissolved oxygen in a polymer. This model causes a significant deviation between the theoretical simulation and the experimental results. Therefore, we propose a modified monomer diffusion model, which is more consistent with experimental results on refractive index modulation than other models.
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Semkin A, Sharangovich S. Holographic Formation of Non-uniform Diffraction Structures by Arbitrary Polarized Recording Beams in Liquid Crystal-photopolymer Compositions. Polymers (Basel) 2019; 11:polym11050861. [PMID: 31083580 PMCID: PMC6571608 DOI: 10.3390/polym11050861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/04/2019] [Accepted: 05/09/2019] [Indexed: 11/16/2022] Open
Abstract
In this work, the theoretical model of non-uniform diffraction structures’ holographic formation in liquid crystal-photopolymer (LC-PPM) composite materials with a dye-sensitizer is developed. The model takes into account the arbitrary character of amplitude and phase spatial distributions of recording light field, its arbitrary polarization state and also a non-linearity of the recording process. Two the most common types of liquid crystal-photopolymer composite are investigated: Holographic polymer-dispersed liquid crystals (H-PDLC) and polymer-stabilized liquid crystals (PSLC). Numerical simulations for the most common cases of holographic formation schemes are made. It is shown that due to the photo-induced Freedericksz transition, in the case of arbitrary polarization states of recording light beams, the non-uniform polarization diffraction grating (PDG) is formed in LC-PPM. Numerical simulations’ results show that PDG’s contribution to the change of the dielectric tensor of the media is comparable with the contribution of the photopolymerization-diffusion process.
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Affiliation(s)
- Artem Semkin
- Department of Microwave and Quantum Radio Engineering, Tomsk State University of Control Systems and Radioelectronics, 634050, Tomsk, Russia.
| | - Sergey Sharangovich
- Department of Microwave and Quantum Radio Engineering, Tomsk State University of Control Systems and Radioelectronics, 634050, Tomsk, Russia.
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Malallah R, Li H, Qi Y, Cassidy D, Muniraj I, Al-Attar N, Sheridan JT. Improving the uniformity of holographic recording using multi-layer photopolymer: Part II. Experimental results. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:334-344. [PMID: 30874186 DOI: 10.1364/josaa.36.000334] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 01/11/2019] [Indexed: 06/09/2023]
Abstract
In the first part of this study, a 3D nonlocal photopolymerization driven diffusion model was developed and applied to simulate the absorption and polymerization taking place during holographic exposures of a multi-layer. The Beer-Lambert law was used to choose appropriate dye concentrations for each layer, with the objective of improving the resulting volume grating uniformity and thus diffraction characteristics. The predictions made, using previously estimated physical parameter values, indicated that improvements in the uniformity of the recorded modulation were possible. In this paper the results of experiments carried out to explore the validity of these predictions are presented. Improvements in material response are demonstrated experimentally, with improved grating diffraction (narrower angular selectivity) being observed for appropriately sensitized multi-layers.
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