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Kawagoe Y, Kikugawa G, Shirasu K, Kinugawa Y, Okabe T. Dissipative Particle Dynamics Simulation for Reaction-Induced Phase Separation of Thermoset/Thermoplastic Blends. J Phys Chem B 2024; 128:2018-2027. [PMID: 38373192 PMCID: PMC10911110 DOI: 10.1021/acs.jpcb.3c07756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/05/2024] [Accepted: 02/08/2024] [Indexed: 02/21/2024]
Abstract
Reaction-induced phase separation occurs during the curing reaction when a thermoplastic resin is dissolved in a thermoset resin, which enables toughening of the thermoset resin. As resin properties vary significantly depending on the morphology of the phase-separated structure, controlling the morphology formation is of critical importance. Reaction-induced phase separation is a phenomenon that ranges from the chemical reaction scale to the mesoscale dynamics of polymer molecules. In this study, we performed curing simulations using dissipative particle dynamics (DPD) coupled with a reaction model to reproduce reaction-induced phase separation. The curing reaction properties of the thermoset resin were determined by ab initio quantum chemical calculations, and the DPD parameters were determined by all-atom molecular dynamics simulations. This enabled mesoscopic simulations, including reactions that reflect the intrinsic material properties. The effects of the thermoplastic resin concentration, molecular weight, and curing conditions on the phase-separation morphology were evaluated, and the cure shrinkage and stiffness of each cured resin were confirmed to be consistent with the experimental trends. Furthermore, the local strain field under tensile deformation was visualized, and the inhomogeneous strain field caused by the phase-separated structures of two resins with different stiffnesses was revealed. These results can aid in understanding the toughening properties of thermoplastic additives at the molecular level.
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Affiliation(s)
- Yoshiaki Kawagoe
- Department
of Aerospace Engineering, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Gota Kikugawa
- Institute
of Fluid Science, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Keiichi Shirasu
- Department
of Finemechanics, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Yuuki Kinugawa
- Department
of Aerospace Engineering, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Tomonaga Okabe
- Department
of Aerospace Engineering, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
- Department
of Materials Science and Engineering, University
of Washington, P.O. Box 352120, Seattle, Washington 98195-1750, United States
- Research
Center for Structural Materials, Polymer Matrix Hybrid Composite Materials
Group, National Institute for Materials
Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
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2
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Yempally S, Kacem E, Ponnamma D. Influence of phase-separated structural morphologies on the piezo and triboelectric properties of polymer composites. DISCOVER NANO 2023; 18:93. [PMID: 37392317 DOI: 10.1186/s11671-023-03868-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023]
Abstract
Simplified and flexible fabrication methods, high output performance, and extreme flexibility of polymer-based nanocomposites represent versatile designs in self-powering devices for wearable electronics, sensors, and smart societies. Examples include polyvinylidene fluoride and its copolymers-based piezoelectric nanogenerators, green and recyclable triboelectric nanogenerators, etc. Advanced functionalities, multi-functional properties, and the extensive lifetime required for nanogenerators inspire researchers to focus on structural modifications of the polymeric materials, to fully exploit their performances. Phase separation is a physicochemical process in which polymeric phases rearrange, resulting in specific structures and properties, that ultimately influence mechanical, electronic, and other functional properties. This article will study the phase separation strategies used to modify the polymeric base, both physically and chemically, to generate the maximum electric power upon mechanical and frictional deformation. The effect of interfacial modification on the efficiency of the nanogenerators, chemical and mechanical stability, structural integrity, durable performance, and morphological appearance will be extensively covered in this review. Moreover, piezo- and triboelectric power generation have numerous challenges, such as poor resistance to mechanical deformation, reduced cyclic performance stability, and a high cost of production. These often depend on the method of developing the nanogenerators, and phase separation provides a unique advantage in reducing them. The current review provides a one-stop solution to understand and disseminate the phase separation process, types and mechanisms, advantages, and role in improving the piezoelectric and triboelectric performances of the nanogenerators.
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Affiliation(s)
- Swathi Yempally
- Center for Advanced Materials, Qatar University, P O Box 2713, Doha, Qatar
| | - Eya Kacem
- Materials Science and Technology Program, Department of Mathematics, Statistics and Physics, College of Arts and Sciences, Qatar University, 2713, Doha, Qatar
| | - Deepalekshmi Ponnamma
- Materials Science and Technology Program, Department of Mathematics, Statistics and Physics, College of Arts and Sciences, Qatar University, 2713, Doha, Qatar.
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3
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Kakiuchida H, Matsuyama A, Kobayashi E, Ogiwara A. Thermoresponsive mobility of liquid crystals and reactive mesogens during photopolymerization-induced phase separation. Phys Rev E 2022; 106:044704. [PMID: 36397491 DOI: 10.1103/physreve.106.044704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Molecular interactions between liquid crystals (LCs) and reactive mesogens (RMs) at temperatures across the phase transition regions were comprehensively studied during photopolymerization-induced phase separation (PPIPS) beginning with raw mixtures until the formation of polymer network liquid crystals (PNLCs). Then, the molecules were found to be nonuniformly more and less mobile in response to temperature as PPIPS progressed. Optical birefringence and infrared absorption were carefully measured throughout PPIPS, using 4-cyano-4'-hexylbiphenyl (6CB) and 1,4bis-[4-(3-acryloyloxypropyloxy) benzoyloxy]-2-methylbenzene (RM257) as typical LCs and RMs. Microscopic views of thermoresponsive changes in the molecular orientation order of both LCs and RMs were obtained: LCs and RMs in raw mixtures interacted with one another but uniformly transformed their molecular orientation. Such interactions continuously change to become nonuniform with progress in PPIPS. At the incipient stages of PPIPS, RMs, which are polymerized but not completely networked, inhibit LCs from changing their molecular orientation and vice versa. As PPIPS progresses, some LCs become more mobile and some less mobile owing to RM constraints. The domain configuration of the submicrometer phase separation affects the thermoresponsive mobility of LCs and RMs, that is, LCs become more mobile in LC-richer areas. The quantitative knowledge here provides comprehensive insight that LCs and RMs are mutually constrained and that such interactive behavior varies nonuniformly as PPIPS progresses.
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Affiliation(s)
- Hiroshi Kakiuchida
- Innovative Functional Materials Research Institute, National Institute of Advanced Industrial Science and Technology, Nagoya 463-8560, Japan
| | - Akihiko Matsuyama
- Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka 820-8502, Japan
| | | | - Akifumi Ogiwara
- Department of Electronic Engineering, Kobe City College of Technology, Kobe 651-2194, Japan
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4
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Ding N, Hosein ID. Simulations of Structure and Morphology in Photoreactive Polymer Blends under Multibeam Irradiation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:6700-6715. [PMID: 35493698 PMCID: PMC9037196 DOI: 10.1021/acs.jpcc.1c09993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/21/2022] [Indexed: 06/14/2023]
Abstract
We present a theoretical study of the organization of photoreactive polymer blends under irradiation by multiple arrays of intersecting optical beams. In a simulated medium possessing an integrated intensity-dependent refractive index, optical beams undergo self-focusing and reduced divergence. A corresponding intensity-dependent increase in molecular weight induces polymer blend instability and consequent phase separation, whereby the medium can evolve into an intersecting waveguide lattice structure, comprising high refractive index cylindrical cores and a surrounding low refractive index medium (cladding). We conduct simulations for two propagation angles and a range of thermodynamic, kinetic, and polymer blend parameters to establish correlations to structure and morphology. We show that spatially correlated structures, namely, those that have a similar intersecting three-dimensional (3D) pattern as the arrays of intersecting optical beams, are achieved via a balance between the competitive processes of photopolymerization rate and phase separation dynamics. A greater intersection angle of the optical beams leads to higher correlations between structures and the optical beam pattern and a wider parameter space that achieves correlated structures. This work demonstrates the potential to employ complex propagating light patterns to create 3D organized structures in multicomponent photoreactive soft systems.
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Bao X, Li H, Zhang H. Model for the phase separation of poly(N-isopropylacrylamide)-clay nanocomposite hydrogel based on energy-density functional. Phys Rev E 2020; 101:062118. [PMID: 32688525 DOI: 10.1103/physreve.101.062118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
The time-dependent Ginzburg-Landau (TDGL) mesoscopic method is utilized to simulate the phase separation of the poly(N-isopropylacrylamide)-clay nanocomposite hydrogel in the three-dimensional case, where the Cahn-Hilliard-Cook equation with a proposed free energy, which consists of the stretching and mixing energy based on Flory's mean theory, is considered. The main features of the presently proposed model include the following: (i) the proposed free energy consists of both the stretching and mixing energy; (ii) the processes of polymer chains detaching from and reattaching on crosslinks are considered in the proposed free energy; (iii) polymer chains have inhomogeneous chain lengths, which are divided into different types. A stabilized semi-implicit difference scheme is used to numerically solve the corresponding Cahn-Hilliard-Cook equation. Numerical results show the process of the phase separation and are consistent with morphology of the nanocomposite hydrogel.
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Affiliation(s)
- Xuelian Bao
- School of Mathematical Sciences, Beijing Normal University, Beijing, 100875, P.R. China
| | - Hua Li
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Republic of Singapore
| | - Hui Zhang
- Laboratory of Mathematics and Complex Systems, Ministry of Education and School of Mathematical Sciences, Beijing Normal University, Beijing, 100875, P.R. China
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Bouchaour T, Bouberka Z, Dali Youcef B, Maschke U. Kinetic analysis of the swelling behavior of poly( n-butylacrylate-1,6-hexanedioldiacrylate) networks in 4-cyano-4′- n-pentyl-biphenyl (5CB). J Appl Polym Sci 2017. [DOI: 10.1002/app.45452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Tewfik Bouchaour
- Unité Matériaux et Transformations-UMET (UMR CNRS No. 8207), Bâtiment C6; Université Lille 1-Sciences et Technologies; Villeneuve d'Ascq Cedex 59655 France
- Laboratoire de Recherche sur les Macromolécules (LRM); Faculté des Sciences, Université Aboubakr Belkaïd; Tlemcen 13000 Algeria
| | - Zohra Bouberka
- Unité Matériaux et Transformations-UMET (UMR CNRS No. 8207), Bâtiment C6; Université Lille 1-Sciences et Technologies; Villeneuve d'Ascq Cedex 59655 France
- Laboratoire Physico-Chimie des Matériaux-Catalyse et Environnement (LPCM-CE); Université des Sciences et de la Technologie d'Oran, USTO; BP 1505, El M'naouer Oran 31000 Algeria
| | - Boumédiène Dali Youcef
- Unité Matériaux et Transformations-UMET (UMR CNRS No. 8207), Bâtiment C6; Université Lille 1-Sciences et Technologies; Villeneuve d'Ascq Cedex 59655 France
- Laboratoire de Recherche sur les Macromolécules (LRM); Faculté des Sciences, Université Aboubakr Belkaïd; Tlemcen 13000 Algeria
| | - Ulrich Maschke
- Unité Matériaux et Transformations-UMET (UMR CNRS No. 8207), Bâtiment C6; Université Lille 1-Sciences et Technologies; Villeneuve d'Ascq Cedex 59655 France
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7
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Biria S, Morim DR, An Tsao F, Saravanamuttu K, Hosein ID. Coupling nonlinear optical waves to photoreactive and phase-separating soft matter: Current status and perspectives. CHAOS (WOODBURY, N.Y.) 2017; 27:104611. [PMID: 29092420 DOI: 10.1063/1.5001821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nonlinear optics and polymer systems are distinct fields that have been studied for decades. These two fields intersect with the observation of nonlinear wave propagation in photoreactive polymer systems. This has led to studies on the nonlinear dynamics of transmitted light in polymer media, particularly for optical self-trapping and optical modulation instability. The irreversibility of polymerization leads to permanent capture of nonlinear optical patterns in the polymer structure, which is a new synthetic route to complex structured soft materials. Over time more intricate polymer systems are employed, whereby nonlinear optical dynamics can couple to nonlinear chemical dynamics, opening opportunities for self-organization. This paper discusses the work to date on nonlinear optical pattern formation processes in polymers. A brief overview of nonlinear optical phenomenon is provided to set the stage for understanding their effects. We review the accomplishments of the field on studying nonlinear waveform propagation in photopolymerizable systems, then discuss our most recent progress in coupling nonlinear optical pattern formation to polymer blends and phase separation. To this end, perspectives on future directions and areas of sustained inquiry are provided. This review highlights the significant opportunity in exploiting nonlinear optical pattern formation in soft matter for the discovery of new light-directed and light-stimulated materials phenomenon, and in turn, soft matter provides a platform by which new nonlinear optical phenomenon may be discovered.
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Affiliation(s)
- Saeid Biria
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA
| | - Derek R Morim
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Fu An Tsao
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Kalaichelvi Saravanamuttu
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Ian D Hosein
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA
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8
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Spatial Frequency Responses of Anisotropic Refractive Index Gratings Formed in Holographic Polymer Dispersed Liquid Crystals. MATERIALS 2016; 9:ma9030188. [PMID: 28773314 PMCID: PMC5456659 DOI: 10.3390/ma9030188] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 02/24/2016] [Accepted: 02/29/2016] [Indexed: 11/16/2022]
Abstract
We report on an experimental investigation of spatial frequency responses of anisotropic transmission refractive index gratings formed in holographic polymer dispersed liquid crystals (HPDLCs). We studied two different types of HPDLC materials employing two different monomer systems: one with acrylate monomer capable of radical mediated chain-growth polymerizations and the other with thiol-ene monomer capable of step-growth polymerizations. It was found that the photopolymerization kinetics of the two HPDLC materials could be well explained by the autocatalytic model. We also measured grating-spacing dependences of anisotropic refractive index gratings at a recording wavelength of 532 nm. It was found that the HPDLC material with the thiol-ene monomer gave higher spatial frequency responses than that with the acrylate monomer. Statistical thermodynamic simulation suggested that such a spatial frequency dependence was attributed primarily to a difference in the size of formed liquid crystal droplets due to different photopolymerization mechanisms.
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9
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Zhang G, Liu G, Shi Z, Qiao G. Dynamics of spinodal decomposition coupled with chemical reaction in thermosetting phenol-formaldehyde resin-based solutions and its application in monolithic porous materials. RSC Adv 2014. [DOI: 10.1039/c3ra46490c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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10
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Wang Q, Hiroshima H, Atobe H. A Dynamic System to evaluate the UV Shrinkage Characteristics of UV Photopolymers used for Nanoimprint. J PHOTOPOLYM SCI TEC 2010. [DOI: 10.2494/photopolymer.23.33] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Rathi P, Park SJ, Kyu T. Effects of photointensity gradient on directional crystal growth in blends of crystalline polymer and photoreactive monomer undergoing photopolymerization-induced phase transformation. J Chem Phys 2009; 130:174904. [DOI: 10.1063/1.3126663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Rathi P, Kyu T. Theory and computation of photopolymerization-induced phase transition and morphology development in blends of crystalline polymer and photoreactive monomer. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:031802. [PMID: 19391963 DOI: 10.1103/physreve.79.031802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Indexed: 05/27/2023]
Abstract
A hypothetical phase diagram of a crystalline polymer/photoreactive monomer mixture has been calculated on the basis of phase field (PF) free energy of crystal solidification in conjunction with Flory-Huggins (FH) free energy of liquid-liquid demixing to guide the morphology development during photopolymerization of poly(ethylene oxide)/triacrylate blend. The self-consistent solution of the combined PF-FH theory exhibits a crystalline-amorphous phase diagram showing the coexistence of solid+liquid gap bound by the liquidus and solidus lines, followed by an upper critical solution temperature at a lower temperature. When photopolymerization was triggered in the isotropic region, i.e., slightly above the crystal melting transition temperatures, the depressed melting transition line moves upward. When it surpasses the reaction temperature, both crystallization and phase separation occur. The temporal evolution of phase morphology is examined in the context of time-dependent Ginzburg-Landau equations coupled with the energy balance (heat conduction) equation using the aforementioned PF-FH free-energy densities. Of particular interest is that the emerged morphology in the crystalline blends depends on the competition between dynamics of liquid-liquid phase separation and/or liquid-solid phase transition (i.e., crystallization) and photopolymerization rates.
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Affiliation(s)
- Pankaj Rathi
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, USA
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13
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Park SJ, Rathi P, Kyu T. Photopolymerization-induced directional crystal growth in reactive mixtures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:051804. [PMID: 17677090 DOI: 10.1103/physreve.75.051804] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Indexed: 05/16/2023]
Abstract
Photopolymerization-induced crystallization has been demonstrated in blends of polyethylene oxide-diacrylate at temperatures above the depressed melting temperature of the crystalline component. Upon exposure to ultraviolet irradiation, the melting transition curve moves upward and eventually surpasses the reaction temperature, thereby inducing phase separation as well as crystallization. The present paper demonstrates the occurrence of directionally solidified interface morphologies of polymer crystals subjected to a photointensity gradient. The epitaxially grown seaweed or degenerate structures were observed at the circumference (low-intensity region) while the dense branched spherulites developed at the core high-intensity region.
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Affiliation(s)
- Soo Jeoung Park
- Department of Polymer Engineering, University of Akron, Akron, OH 44325, USA
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14
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Crawford N, Dadmun M, Bunning T, Natarajan L. Time-resolved light scattering of the phase separation in polymer-dispersed liquid crystals formed by photo-polymerization induced phase separation. POLYMER 2006. [DOI: 10.1016/j.polymer.2006.06.058] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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16
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Jin MY, Lee YJ, Lee K, Lee SD, Kim JH. Physical mechanism for in-plane molecular orientation in polymer-dispersed ferroelectric liquid crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:031703. [PMID: 16605542 DOI: 10.1103/physreve.73.031703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Indexed: 05/08/2023]
Abstract
The physical mechanism of liquid crystal (LC) alignment in ferroelectric LC (FLC) droplets dispersed in a photocurable polymer matrix was studied. The orientational ordering of both FLC molecules and the polymer matrix was induced by a rubbed polyimide alignment layer. There existed an optimum FLC droplet size for the production of uniformly oriented molecules and smectic layers for maximum electro-optic modulation. The alignment quality was critically dependent on the droplet size, shape, the helical pitch, and the phase transition sequence of the FLCs. The molecular structure formed inside the FLC droplets resulted from a delicate balance between the elastic energy stored in a restricted geometry and surface interactions at the FLC-polymer interface.
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Affiliation(s)
- Min Young Jin
- Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791, Korea
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17
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Xia J, Wang J, Lin Z, Qiu F, Yang Y. Phase Separation Kinetics of Polymer Dispersed Liquid Crystals Confined between Two Parallel Walls. Macromolecules 2006. [DOI: 10.1021/ma0527045] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jianfeng Xia
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Jun Wang
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Zhiqun Lin
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Feng Qiu
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Yuliang Yang
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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Meng S, Kyu T, Natarajan LV, Tondiglia VP, Sutherland RL, Bunning TJ. Holographic Photopolymerization-Induced Phase Separation in Reference to the Phase Diagram of a Mixture of Photocurable Monomer and Nematic Liquid Crystal. Macromolecules 2005. [DOI: 10.1021/ma0480906] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Scott Meng
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Thein Kyu
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Lalgudi V. Natarajan
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Vincent P. Tondiglia
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Richard L. Sutherland
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Timothy J. Bunning
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
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Lin YH, Ren H, Wu YH, Liang X, Wu ST. Pinning effect on the phase separation dynamics of thin polymer-dispersed liquid crystals. OPTICS EXPRESS 2005; 13:468-474. [PMID: 19488374 DOI: 10.1364/opex.13.000468] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The surface pining effects on phase separation dynamics of polymer-dispersed liquid crystals (PDLCs) with thin cell gaps are demonstrated. Comparing various boundary conditions, the inner surfaces of the substrates with or without polyimide layers [but no rubbing] cannot provide enough anchoring force, so in either case the liquid crystal (LC) droplets flow and coalesce to form larger and less uniform droplets. However, if the inner surfaces of the substrates are coated with rubbed polyimide layers with anchoring energy >1x10-4 J/m2, almost all the nucleated LC droplets grow at a fixed position during phase separation. The appearance of the coalescence is not obvious and the formed LC droplets are relatively uniform. The surface anchoring has a significant effect on the morphology of PDLCs.
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20
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Meng S, Nanjundiah K, Kyu T, Natarajan LV, Tondiglia VP, Bunning TJ. Transport Controlled Pattern Photopolymerization in a Single-Component System. Macromolecules 2004. [DOI: 10.1021/ma0356055] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Scott Meng
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Kumar Nanjundiah
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Thein Kyu
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Lalgudi V. Natarajan
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Vincent P. Tondiglia
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
| | - Timothy J. Bunning
- Department of Polymer Engineering, University of Akron, Akron, Ohio 44325; Science Applications International Corporation, Dayton, Ohio 45431; and Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433
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Kwok AY, Prime EL, Qiao GG, Solomon DH. Synthetic hydrogels 2. Polymerization induced phase separation in acrylamide systems. POLYMER 2003. [DOI: 10.1016/j.polymer.2003.09.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bouchaour T, Benmouna F, Coqueret X, Benmouna M, Maschke U. Swelling of crosslinked polyacrylates in isotropic and anisotropic solvents. J Appl Polym Sci 2003. [DOI: 10.1002/app.12608] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kyu T, Nwabunma D. Simulations of Microlens Arrays Formed by Pattern-Photopolymerization-Induced Phase Separation of Liquid Crystal/Monomer Mixtures. Macromolecules 2001. [DOI: 10.1021/ma010567f] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thein Kyu
- Institute of Polymer Engineering, The University of Akron, Akron, Ohio 44325-0301
| | - Domasius Nwabunma
- Institute of Polymer Engineering, The University of Akron, Akron, Ohio 44325-0301
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Kyu T, Chiu HW. Morphology development during polymerization-induced phase separation in a polymer dispersed liquid crystal. POLYMER 2001. [DOI: 10.1016/s0032-3861(01)00389-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kyu T, Nwabunma D, Chiu HW. Theoretical simulation of holographic polymer-dispersed liquid-crystal films via pattern photopolymerization-induced phase separation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:061802. [PMID: 11415131 DOI: 10.1103/physreve.63.061802] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2000] [Indexed: 05/06/2023]
Abstract
A theoretical simulation has been performed to elucidate the emergence of nematic domains during pattern photopolymerization-induced phase separation in holographic polymer-dispersed liquid crystals. We consider a reference system consisting of a single-component nematic, namely, 4-n-heptyl-4(')-cyanobiphenyl (T(NI)=42 degrees C), and a polymer network made from multifunctional monomers. To mimic pattern photopolymerization, the reaction rate was varied periodically in space through wave mixing. In the theoretical development, the photopolymerization kinetics was coupled with the time-dependent Ginzburg-Landau model C equations by incorporating the local free energy densities pertaining to isotropic liquid-liquid mixing, nematic ordering, and network elasticity. The simulated morphological patterns in the concentration and orientation order parameter fields show discrete layers of liquid-crystal droplets alternating periodically with polymer-network-rich layers. The Fourier transforms of these patterns show sharp diffraction spots arising from the periodic layers. As the layer thickness is reduced, the liquid-crystal molecules are confined in the narrow stripes. The liquid-crystal domains appear uniform along the stripes, which in turn gives rise to sharper diffraction spots in Fourier space. Of particular interest is that our simulated stratified patterns are in qualitative agreement with reported experimental observations.
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Affiliation(s)
- T Kyu
- Institute of Polymer Engineering, The University of Akron, Akron, Ohio 44325, USA.
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