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Tanaka S, Takezawa Y, Kanie K, Muramatsu A. Forming a Homeotropic SmA Structure of Liquid Crystalline Epoxy Resin on an Amine-Modified Surface. ACS OMEGA 2023; 8:32365-32371. [PMID: 37720757 PMCID: PMC10500675 DOI: 10.1021/acsomega.3c01498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 07/14/2023] [Indexed: 09/19/2023]
Abstract
The molecular orientation of a liquid crystalline (LC) epoxy resin (LCER) on silane coupling surfaces of amorphous soda-lime-silica glass substrates was investigated. The LC epoxy monomer on the silane coupling surfaces of the substrates was revealed to form a smectic A (SmA) phase with planar alignments because of the relatively low surface free energy. An LCER with a curing agent, however, formed a homeotropically aligned SmA structure by curing on a substrate surface modified using a silane coupling agent with amino groups. This formation of homeotropic alignment was considered due to the attribution of the reaction between the amino group on the surface of the substrate and the epoxy group of the LCER. The homeotropic alignment had a relatively high orientation parameter of 0.95. Therefore, it is expected to possess high thermal conductivity and be applied as high-thermal-conductivity adhesives or packaging materials for electrical and electronic devices.
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Affiliation(s)
- Shingo Tanaka
- Research
& Development Group, Hitachi, Ltd., 7-1-1 Omika, Hitachi 319-1292, Ibaraki, Japan
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Miyagi, Japan
| | - Yoshitaka Takezawa
- Advanced
Technology Research & Development Center, Showa Denko Materials Co., Ltd., 48 Wadai, Tsukuba 300-4247, Ibaraki, Japan
| | - Kiyoshi Kanie
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Miyagi, Japan
- International
Center for Synchrotron Radiation Innovation Smart, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Miyagi, Japan
| | - Atsushi Muramatsu
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Miyagi, Japan
- International
Center for Synchrotron Radiation Innovation Smart, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Miyagi, Japan
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2
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Tanaka S, Takezawa Y, Kanie K, Muramatsu A. Homeotropically Aligned Monodomain-like Smectic-A Structure in Liquid Crystalline Epoxy Films: Analysis of the Local Ordering Structure by Microbeam Small-Angle X-ray Scattering. ACS OMEGA 2020; 5:20792-20799. [PMID: 32875213 PMCID: PMC7450511 DOI: 10.1021/acsomega.0c01603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/30/2020] [Indexed: 06/11/2023]
Abstract
For the development of functional thin films with high thermal conductivity, the local ordering structure of a cured liquid crystalline epoxy resin (LCER) droplet was investigated by using synchrotron radiation microbeam small-angle X-ray scattering. The cured LCER in the vicinity of a substrate with low surface free energy was revealed to form a polydomain smectic-A (SmA) structure in which the normal direction of the layers was random in each domain, although the alignment was planar near the air interface. On the other hand, the cured LCER on a substrate with high surface free energy formed a homeotropically aligned SmA structure in the region within 21 μm from the surface of the substrate. Therefore, a 20 μm thick LCER film was fabricated and found to form a homeotropically aligned monodomain-like SmA structure throughout the whole film with a high thermal conductivity (0.81-5.8 W m-1 K-1). This film with a high thermal conductivity is expected to be applicable for adhesion and precoating materials for electrical and electronic devices.
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Affiliation(s)
- Shingo Tanaka
- Advanced
Technology Research & Development Center, Hitachi Chemical Company, Ltd., 48 Wadai, Tsukuba, Ibaraki 300-4247, Japan
- Research
& Development Group, Hitachi, Ltd., 7-1-1 Omika, Hitachi, Ibaraki 319-1292, Japan
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Yoshitaka Takezawa
- Advanced
Technology Research & Development Center, Hitachi Chemical Company, Ltd., 48 Wadai, Tsukuba, Ibaraki 300-4247, Japan
| | - Kiyoshi Kanie
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Atsushi Muramatsu
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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3
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Takana H, Guo M. Numerical simulation on electrostatic alignment control of cellulose nano-fibrils in flow. NANOTECHNOLOGY 2020; 31:205602. [PMID: 31986491 DOI: 10.1088/1361-6528/ab703d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The alignment process of the cellulose nano-fibrils (CNFs) in an alternating electric field and elongational flow is numerically simulated for the fabrication of strong cellulose filaments. The order parameter of CNFs in the flow channel is evaluated by solving the Smoluchowski equation for the orientation distribution function of the CNFs. The results show that CNF alignment in the electric field is enhanced with applied voltage because the electrostatic torque is dominant over the Brownian rotation. An optimal fibril length is shown to exist for electrostatic alignment coupled with elongational flow effect.
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Affiliation(s)
- Hidemasa Takana
- Institute of Fluid Science, Tohoku University, Sendai, Japan
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4
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Curing Reaction and Dielectric Properties of Rigid and Elastic Liquid Crystal Epoxy Networks Modified with Nanofillers. INT J POLYM SCI 2018. [DOI: 10.1155/2018/9578654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The aim of the paper is to compare the progress of the curing reaction and the dielectric properties of liquid crystalline epoxy networks of different elasticity and to investigate how modification with nanofillers influences their properties. The study focuses on a liquid crystalline epoxy monomer with four aromatic rings in the mesogen, cross-linked with 4,4′-diaminodiphenylmethane (DDM) and pimelic acid (PA) to produce rigid and elastic polymer networks. The obtained results are compared to networks modified with nanofillers (diphenyl aluminum phosphate nanorods). The curing process is monitored in situ with broadband dielectric spectroscopy, which is a good tool to view the progress of the reaction. Two stages with different reaction dynamics are observed in the studied cases. Dielectric properties of the products cured with two chosen agents show significant differences in the obtained parameters (activation energy, glass transition, and fragility index) as well as in the dynamics of the α and β relaxations. Although the curing agent is the main factor determining the properties of the product, the nanofiller additive also modifies the values of specific parameters that characterize both the process of the reaction and the properties of the final composites. Particularly, adding the nanofiller raises the glass transition temperature in both the cases. The obtained results are in good agreement with the earlier calorimetric study.
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Włodarska M, Mossety-Leszczak B, Bąk GW, Kisiel M, Dłużniewski M, Okrasa L. Epoxy matrix with triaromatic mesogenic unit in dielectric spectroscopy observation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 194:102-110. [PMID: 29328951 DOI: 10.1016/j.saa.2018.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/14/2017] [Accepted: 01/03/2018] [Indexed: 06/07/2023]
Affiliation(s)
- Magdalena Włodarska
- Institute of Physics, Lodz University of Technology, Wólczańska 219, 90-924 Łódź, Poland.
| | - Beata Mossety-Leszczak
- Department of Industrial and Materials Chemistry, Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland
| | - Grzegorz W Bąk
- Institute of Physics, Lodz University of Technology, Wólczańska 219, 90-924 Łódź, Poland
| | - Maciej Kisiel
- Department of Industrial and Materials Chemistry, Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland
| | - Maciej Dłużniewski
- Institute of Physics, Lodz University of Technology, Wólczańska 219, 90-924 Łódź, Poland
| | - Lidia Okrasa
- Department of Molecular Physics, Lodz University of Technology, Żeromskiego 116, 90-924 Łódź, Poland
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Tanaka S, Hojo F, Takezawa Y, Kanie K, Muramatsu A. Highly Oriented Liquid Crystalline Epoxy Film: Robust High Thermal-Conductive Ability. ACS OMEGA 2018; 3:3562-3570. [PMID: 31458608 PMCID: PMC6641456 DOI: 10.1021/acsomega.7b02088] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 03/15/2018] [Indexed: 06/10/2023]
Abstract
The molecular orientation effect of a liquid crystalline (LC) epoxy resin (LCER) on thermal conductivity was investigated, with the thermal conductivity depending on the surface free energy of amorphous soda-lime-silica glass substrate surfaces modified using physical surface treatments. The LC epoxy monomer was revealed to form a smectic A (SmA) phase with homeotropic alignments on the surfaces of substrates that possess high surface free energies of 71.3 and 72.7 mN m-1, but forming a planar alignment on the surface of a substrate that possesses a relatively low surface free energy of 46.3 mN m-1. The optical microscopy observations and the X-ray analyses revealed that the LC epoxy monomer also induced a homeotropically aligned SmA structure due to cross-linking with a curing agent on the high-free-energy surface. The orientational order parameter of the resulting homeotropic SmA structure was calculated from the grazing incidence small-angle X-ray scattering patterns to be 0.73-0.75. The thermal conductivity of the cross-linked LCER forming a homeotropically aligned SmA structure was also estimated to be 2.0 and 5.8 W m-1 K-1 for the average and maximum in the direction of the Sm layer normal. The value of the thermal conductivity was remarkable among the thermosetting polymers and ceramic glass, and the LCER could be applied for high-thermal-conductive adhesives and packaging materials in electrical and electronic devices.
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Affiliation(s)
- Shingo Tanaka
- Research
& Development group, Hitachi, Ltd., 7-1-1 Omika, Hitachi, Ibaraki 319-1292, Japan
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Fusao Hojo
- Research
& Development group, Hitachi, Ltd., 7-1-1 Omika, Hitachi, Ibaraki 319-1292, Japan
| | - Yoshitaka Takezawa
- Advanced
Technology Research & Development Center, Hitachi Chemical Co., Ltd., 48 Wadai, Tsukuba, Ibaraki 300-4247, Japan
| | - Kiyoshi Kanie
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Atsushi Muramatsu
- Institute
of Multidisciplinary Research for Advanced Material, Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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7
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Wang G, Garvey CJ, Zhao H, Huang K, Kong L. Toward the Fabrication of Advanced Nanofiltration Membranes by Controlling Morphologies and Mesochannel Orientations of Hexagonal Lyotropic Liquid Crystals. MEMBRANES 2017; 7:membranes7030037. [PMID: 28753973 PMCID: PMC5618122 DOI: 10.3390/membranes7030037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/10/2017] [Accepted: 07/12/2017] [Indexed: 01/27/2023]
Abstract
Water scarcity has been recognized as one of the major threats to human activity, and, therefore, water purification technologies are increasingly drawing attention worldwide. Nanofiltration (NF) membrane technology has been proven to be an efficient and cost-effective way in terms of the size and continuity of the nanostructure. Using a template based on hexagonal lyotropic liquid crystals (LLCs) and partitioning monomer units within this structure for subsequent photo-polymerisation presents a unique path for the fabrication of NF membranes, potentially producing pores of uniform size, ranging from 1 to 5 nm, and large surface areas. The subsequent orientation of this pore network in a direction normal to a flat polymer film that provides ideal transport properties associated with continuous pores running through the membrane has been achieved by the orientation of hexagonal LLCs through various strategies. This review presents the current progresses on the strategies for structure retention from a hexagonal LLCs template and the up-to-date techniques used for the reorientation of mesochanels for continuity through the whole membrane.
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Affiliation(s)
- Guang Wang
- Institute for Frontier Materials, Deakin University, Locked Bag 20000, Geelong 3220, Australia.
| | - Christopher J Garvey
- Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC 2232, Australia.
| | - Han Zhao
- School of Mechanical Engineering, Hefei University of Technology, No. 193 Tunxi Road, Hefei 230009, China.
| | - Kang Huang
- School of Mechanical Engineering, Hefei University of Technology, No. 193 Tunxi Road, Hefei 230009, China.
| | - Lingxue Kong
- Institute for Frontier Materials, Deakin University, Locked Bag 20000, Geelong 3220, Australia.
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8
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Cho SH, Lee JY, Douglas EP. Synthesis and Thermal Properties of Liquid Crystalline Thermoset containing Rigid-Rod Epoxy. HIGH PERFORM POLYM 2016. [DOI: 10.1177/0954008306056484] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
4,4′-diglycidyloxy- α-methylstilbene (DOMS) and a novel liquid crystalline thermoset, D2A1 which is obtained from the reaction between DOMS and aniline were synthesized. The thermosets have been characterized with cross-polarized optical microscopy, differential scanning calorimetry, thermogravimetric analysis (TGA) and other techniques. D2A1 was smectic at room temperature and turned to nematic at 85°C upon heating, then turned isotropic at 135°C. Activation energies for decomposition ( Ed) using TGA were calculated according to the technique of Flynn-Wall to determine Ed as a function of conversion α by a weight loss process.
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Affiliation(s)
- Seung Hyun Cho
- Polymer Technology Institute, Sungkyunkwan University, Suwon 440-746, Korea
| | - Jun Young Lee
- Polymer Technology Institute, Sungkyunkwan University, Suwon 440-746, Korea
| | - Elliot P. Douglas
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
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9
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Li Y, Rios O, Kessler MR. Thermomagnetic processing of liquid-crystalline epoxy resins and their mechanical characterization using nanoindentation. ACS APPLIED MATERIALS & INTERFACES 2014; 6:19456-19464. [PMID: 25318760 DOI: 10.1021/am505874t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A thermomagnetic processing method was used to produce a biphenyl-based liquid-crystalline epoxy resin (LCER) with oriented liquid-crystalline (LC) domains. The orientation of the LCER was confirmed and quantified using two-dimensional X-ray diffraction. The effect of molecular alignment on the mechanical and thermomechanical properties of the LCER was investigated using nanoindentation and thermomechanical analysis, respectively. The effect of the orientation on the fracture behavior was also examined. The results showed that macroscopic orientation of the LC domains was achieved, resulting in an epoxy network with an anisotropic modulus, hardness, creep behavior, and thermal expansion.
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Affiliation(s)
- Yuzhan Li
- School of Mechanical and Materials Engineering, Washington State University , P.O. Box 642920, Pullman, Washington 99164, United States
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10
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Li Y, Kessler MR. Liquid crystalline epoxy resin based on biphenyl mesogen: Effect of magnetic field orientation during cure. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Wlodarska M, Maj A, Mossety-Leszczak B, Bak GW, Galina H, Okrasa L, Izdebski M. Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy. JOURNAL OF POLYMER RESEARCH 2013. [DOI: 10.1007/s10965-013-0227-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Yuryev Y, Wood-Adams PM. Crystallization of Poly(L
-/D
-Lactide) in the Presence of Electric Fields. MACROMOL CHEM PHYS 2012. [DOI: 10.1002/macp.201100448] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Phillips PM, Mei N, Soulé ER, Reven L, Rey AD. Textures in polygonal arrangements of square nanoparticles in nematic liquid crystal matrices. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:13335-13341. [PMID: 21942338 DOI: 10.1021/la203226g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A systematic analysis of defect textures in faceted nanoparticles with polygonal configurations embedded in a nematic matrix is performed using the Landau-de Gennes model, homeotropic strong anchoring in a square domain with uniform alignment in the outer boundaries. Defect and textures are analyzed as functions of temperature T, polygon size R, and polygon number N. For nematic nanocomposites, the texture satisfies a defect charge balance equation between bulk and surface (particle corner) charges. Upon decreasing the temperature, the central bulk defects split and together with other -1/2 bulk defects are absorbed by the nanoparticle's corners. Increasing the lattice size decreases confinement and eliminates bulk defects. Increasing the polygon number increases the central defect charge at high temperature and the number of surface defects at lower temperatures. The excess energy per particle is lower in even than in odd polygons, and it is minimized for a square particle arrangement. These discrete modeling results show for first time that, even under strong anchoring, defects are attached to particles as corner defects, leaving behind a low energy homogeneous orientation field that favors nanoparticle ordering in nematic matrices. These new insights are consistent with recent thermodynamic approaches to nematic nanocomposites that predict the existence of novel nematic/crystal phases and can be used to design nanocomposites with orientational and positional order.
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Affiliation(s)
- Paul M Phillips
- Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A2B2, Canada
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14
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Koerner H, Ober CK, Xu H. Probing electric field response of LC thermosets via time-resolved X-ray and dielectric spectroscopy. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.03.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Chen Y, Yang Z, Wu XY, Ni CY, Ren ZG, Lang JP. Dielectric anisotropy of the single crystal of isopropylviologen copper(i) triiodide. Phys Chem Chem Phys 2011; 13:10781-6. [DOI: 10.1039/c1cp20422j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Qu ZR, Ye Q, Zhao H, Fu DW, Ye HY, Xiong RG, Akutagawa T, Nakamura T. Homochiral Laminar Europium Metal–Organic Framework with Unprecedented Giant Dielectric Anisotropy. Chemistry 2008; 14:3452-6. [DOI: 10.1002/chem.200701449] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Habibi Y, Heim T, Douillard R. AC electric field-assisted assembly and alignment of cellulose nanocrystals. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/polb.21479] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Huang C, Katz HE, West JE. Solution-processed organic field-effect transistors and unipolar inverters using self-assembled interface dipoles on gate dielectrics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:13223-13231. [PMID: 18020470 DOI: 10.1021/la702409m] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Self-assembled monolayers (SAMs) of polarized and nonpolarized organosilane molecules on gate insulators induced tunable threshold voltage shifting and current modulation in organic field-effect transistors (OFETs) made from solution-deposited 5,5'-bis(4-hexylphenyl)-2,2'-bithiophene (6PTTP6), defining depletion-mode and enhancement-mode operation. p-Channel inverters were made from pairs of OFETs with an enhancement-mode driver and a depletion-mode load to implement full-swing and high-gain organic logic circuits. The experimental results indicate that the shift of the transfer characteristics is governed by the built-in electric field of the SAM. The effect of surface functional groups affixed to the dielectric substrate on the grain appearance and film mobility is also determined.
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Affiliation(s)
- Cheng Huang
- Department of Materials Science and Engineering and Department of Electrical and Computer Engineering, G. W. C. Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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19
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Ye Q, Zhao H, Qu ZR, Fu DW, Xiong RG, Cui YP, Akutagawa T, Chan PWH, Nakamura T. Large anisotropy and effect of deuteration on permittivity in an olefin copper(I) complex. Angew Chem Int Ed Engl 2007; 46:6852-6. [PMID: 17674390 DOI: 10.1002/anie.200700629] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Qiong Ye
- Ordered Matter Science Research Center and School of Electronic Science and Engineering, Southeast University, Nanjing, 211189, China
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20
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Ye Q, Zhao H, Qu ZR, Fu DW, Xiong RG, Cui YP, Akutagawa T, Chan P, Nakamura T. Large Anisotropy and Effect of Deuteration on Permittivity in an Olefin Copper(I) Complex. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200700629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Ku AY, Saville DA, Aksay IA. Electric-field-induced orientation of surfactant-templated nanoscopic silica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:8156-62. [PMID: 17585784 DOI: 10.1021/la0636154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
While exhibiting a well-defined nanometer-level structure, surfactant-templated nanoscopic silicas produced via self-assembly do not always possess long-range order. We demonstrate that long-range order can be controlled by guiding the self-assembly of nanostructured silica-surfactant hybrids with low-strength electric fields (E approximately 200 V/m) to produce nanoscopic silica with both the micrometer- and nanometer-level structures oriented parallel to the applied field. Under the influence of the electric field, nanoscopic silica particles migrate, elongate, and merge into fibers with a rate of migration proportional to the applied field strength. The linear dependence with the field strength indicates that the process is governed by electroosmotic flow but not by polarization effects. Realignment of the short-range ordered surfactant nanochannels along the fiber axis accompanies the migration.
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Affiliation(s)
- Anthony Y Ku
- Department of Chemical Engineering, Princeton University, Princeton, NJ 08544, USA
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22
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Wincure BM, Rey AD. Nanoscale analysis of defect shedding from liquid crystal interfaces. NANO LETTERS 2007; 7:1474-9. [PMID: 17472407 DOI: 10.1021/nl0701408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A new defect-forming mechanism is predicted for liquid crystals undergoing an isotropic-to-nematic phase transition. A continuum theory characterizes how +1/2 defects (D<30 nm) evolve within and then shed from the interface (cross section approximately 100 nm) of a growing 5CB (4-n-4'-pentyl-4-cyanobiphenyl) nanodroplet (20 nm<D<2000 nm). Free energy density, defect core shapes, and the evolving defect core structure are presented at the nanoscale to better understand liquid crystal anisotropy and orientation during interfacial defect shedding.
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Affiliation(s)
- Benjamin M Wincure
- Department of Chemical Engineering and McGill Institute of Advanced Materials, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada
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23
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24
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Lee JY. Transverse alignment of liquid crystalline epoxy resin on carbon fiber surface. J Appl Polym Sci 2006. [DOI: 10.1002/app.24305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Lee JY. Relationship between anisotropic orientation and curing of liquid crystalline epoxy resin. J Appl Polym Sci 2006. [DOI: 10.1002/app.24352] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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27
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Al-Haik MS, Garmestani H, Li DS, Hussaini MY, Sablin SS, Tannenbaum R, Dahmen K. Mechanical properties of magnetically oriented epoxy. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20037] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Controlled local organization of lyotropic liquid crystalline polymer thin films with electric fields. POLYMER 2002. [DOI: 10.1016/s0032-3861(02)00256-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Park C, Robertson R. Crystallization of poly(ethylene oxide) in a photopolymerizable monomer under an electric field. POLYMER 2001. [DOI: 10.1016/s0032-3861(00)00591-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jones MA, Bohn PW. Total Internal Reflection Fluorescence and Electrocapillary Investigations of Adsorption at the Water−Dichloroethane Electrochemical Interface. 2. Fluorescence-Detected Linear Dichroism Investigation of Adsorption-Driven Reorientation of Di-N-butylaminonaphthylethenylpyridiniumpropylsulfonate. J Phys Chem B 2001. [DOI: 10.1021/jp002370f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. A. Jones
- Department of Chemistry, Materials Research Laboratory, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
| | - P. W. Bohn
- Department of Chemistry, Materials Research Laboratory, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801
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Cheng SX, Chung TS. Dynamic Responses of a Thermotropic Main-Chain Liquid Crystalline Polyester during Polymerization under Electric Fields. J Phys Chem B 2000. [DOI: 10.1021/jp000518p] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Si-Xue Cheng
- Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, and Department of Chemical and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - Tai-Shung Chung
- Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, and Department of Chemical and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
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Bunning TJ, Adams W, Ober CK, Korner H. Synchrotron Radiation for Probing the Electric Field Alignment of LC Macromolecules and Polymers. INT J POLYM MATER PO 2000. [DOI: 10.1080/00914030008035051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Fitz BD, Mijovic J. Molecular Dynamics in Cyanate Ester Resin Networks and Model Cyanurate Compounds. Macromolecules 2000. [DOI: 10.1021/ma9911243] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Benjamin D. Fitz
- Block Drug Company, Inc., Research and Technologies Laboratories, 257 Cornelison Ave., Jersey City, New Jersey 07302, and Department of Chemical Engineering, Chemistry and Materials Science, Polytechnic University, 6 Metrotech Center, Brooklyn, New York 11201
| | - Jovan Mijovic
- Block Drug Company, Inc., Research and Technologies Laboratories, 257 Cornelison Ave., Jersey City, New Jersey 07302, and Department of Chemical Engineering, Chemistry and Materials Science, Polytechnic University, 6 Metrotech Center, Brooklyn, New York 11201
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Abstract
The effect of magnetic fields on the orientation and properties of 4,4'-bis(2,3-epoxypropoxy)-alpha-methylstilbene cured with sulfanilamide has been studied. This epoxy system is initially isotropic and forms a smectic A phase upon curing. A magnetic field was applied during the cure reaction, resulting in alignment of the molecules along the direction of the applied field. Measurement of the orientation parameter of the fully cured material by wide-angle X-ray scattering (WAXS) showed that orientation improved with an increase in field strength. The orientation parameters of the smectic layer normals calculated from the inner reflection of the WAXS pattern attained a maximum level of approximately 0.8 at a field strength of approximately 12 T. The orientation parameters calculated from the outer reflection of the WAXS pattern were considerably lower, possibly due to the presence of amorphous regions associated with domain boundaries or the loss of molecular alignment within the smectic layers due to topological restrictions of the cross-linking sites. Orientation resulted in an anisotropic linear thermal expansion coefficient after curing, although the overall volumetric expansion was constant. The elastic tensile modulus increased with the square of the orientation parameter, attaining a maximum value of 8.1 GPa, compared to 3.1 GPa for the unoriented material. The change in modulus with orientation could be fit with a simple model for the modulus of anisotropic materials.
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Kurihara S, Iwamoto K, Nonaka T. Preparation and structure of polymer networks by polymerization of liquid crystalline monomers in DC electric field. POLYMER 1998. [DOI: 10.1016/s0032-3861(97)10268-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Steehler J, Lu W, Kemery P, Bohn P. Electric field induced permeability modulation in pure and mixed Langmuir-Blodgett multilayers of hemicyanine dyes and octadecanoic acid on nanoporous solid supports. J Memb Sci 1998. [DOI: 10.1016/s0376-7388(97)00261-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Shiota A, Ober CK. Orientation of Liquid Crystalline Epoxides under ac Electric Fields. Macromolecules 1997. [DOI: 10.1021/ma961745l] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atsushi Shiota
- Department of Materials Science and Engineering, Bard Hall, Cornell University, Ithaca, New York 14853-1501
| | - Christopher K. Ober
- Department of Materials Science and Engineering, Bard Hall, Cornell University, Ithaca, New York 14853-1501
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