76
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Fuchigami Y, Takigawa T, Urayama K. Electrical Actuation of Cholesteric Liquid Crystal Gels. ACS Macro Lett 2014; 3:813-818. [PMID: 35590706 DOI: 10.1021/mz5003382] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate that the cholesteric liquid crystal (CLC) gels with a global helical variation in their orientation exhibit the pronounced electro-optical and electromechanical effects under an unconstrained geometry. A sufficiently high electric field imposed along the helical axis drives a finite elongation exceeding 30% along the field axis, as well as a finite redshift of the selective reflection band which is opposite to the blueshift often observed for the conventional CLCs and the in situ polymer stabilized CLCs under an electric field.
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77
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Katashima T, Asai M, Urayama K, Chung UI, Sakai T. Mechanical properties of tetra-PEG gels with supercoiled network structure. J Chem Phys 2014; 140:074902. [DOI: 10.1063/1.4863917] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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78
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Katsuno C, Konda A, Urayama K, Takigawa T, Kidowaki M, Ito K. Pressure-responsive polymer membranes of slide-ring gels with movable cross-links. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:4636-4640. [PMID: 23836706 DOI: 10.1002/adma.201301252] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/07/2013] [Indexed: 05/28/2023]
Abstract
Polymer membranes comprising slide-ring gels with movable cross-links exhibit a nonlinear pressure-dependence in the fluidic flow rate. The proportional constant between the flow rate and pressure significantly changes at a critical pressure. The slide-ring gels are promising polymer membrane materials, which would allow for the on-off control of fluid permeability using an imposed pressure.
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79
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Sawa Y, Urayama K, Takigawa T, Gimenez-Pinto V, Mbanga BL, Ye F, Selinger JV, Selinger RLB. Shape and chirality transitions in off-axis twist nematic elastomer ribbons. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:022502. [PMID: 24032851 DOI: 10.1103/physreve.88.022502] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Indexed: 06/02/2023]
Abstract
Using both experiments and finite element simulations, we explore the shape evolution of off-axis twist nematic elastomer ribbons as a function of temperature. The elastomers are prepared by cross-linking the mesogens with planar anchoring of the director at top and bottom surfaces with a 90° left-handed twist. Shape evolution depends sensitively on the off-axis director orientation at the sample midplane. Both experiments and theoretical studies show that when the director at midplane is parallel to either the ribbon's long or short axes, ribbons form either helicoids or spirals depending on aspect ratio and temperature. Simulation studies show that if the director at midplane is off-axis, ribbons never form helicoids, instead evolving to distorted spiral shapes. Experimental studies for two samples with off-axis geometry show agreement with this prediction. Samples in all these geometries show a remarkable transition from right- to left-handed chiral shapes on change of temperature. Simulations predict off-axis samples also change their macroscopic chirality at fixed temperature, depending on the angular offset. These results provide insight into the mechanisms driving shape evolution and macroscopic chirality, enabling engineering design of these materials for future applications.
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80
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81
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Higaki H, Takigawa T, Urayama K. Nonuniform and Uniform Deformations of Stretched Nematic Elastomers. Macromolecules 2013. [DOI: 10.1021/ma400771z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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82
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Konda A, Mayumi K, Urayama K, Takigawa T, Ito K. Influence of Structural Characteristics on Stretching-Driven Swelling of Polyrotaxane Gels with Movable Cross Links. Macromolecules 2012. [DOI: 10.1021/ma301089k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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83
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Higaki H, Urayama K, Takigawa T. Memory and Development of Textures of Polydomain Nematic Elastomers. MACROMOL CHEM PHYS 2012. [DOI: 10.1002/macp.201200239] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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84
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Yamazaki H, Takeda M, Kohno Y, Ando H, Urayama K, Takigawa T. Dynamic Viscoelasticity of Poly(butyl acrylate) Elastomers Containing Dangling Chains with Controlled Lengths. Macromolecules 2011. [DOI: 10.1021/ma201941v] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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85
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Bitoh Y, Akuzawa N, Urayama K, Takigawa T, Kidowaki M, Ito K. Peculiar Nonlinear Elasticity of Polyrotaxane Gels with Movable Cross-Links Revealed by Multiaxial Stretching. Macromolecules 2011. [DOI: 10.1021/ma201530z] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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86
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Boulberdaa M, Urayama K, Nebigil CG. Prokineticin receptor 1 (PKR1) signalling in cardiovascular and kidney functions. Cardiovasc Res 2011; 92:191-8. [DOI: 10.1093/cvr/cvr228] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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87
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Konda A, Urayama K, Takigawa T. Strain-Rate-Dependent Poisson’s Ratio and Stress of Polymer Gels in Solvents Revealed by Ultraslow Stretching. Macromolecules 2011. [DOI: 10.1021/ma102767t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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88
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89
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Tada T, Urayama K, Mabuchi T, Muraoka K, Takigawa T. Nonlinear stress relaxation of carbon black-filled rubber vulcanizates under various types of deformation. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/polb.22017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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90
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Sawa Y, Urayama K, Takigawa T, DeSimone A, Teresi L. Thermally Driven Giant Bending of Liquid Crystal Elastomer Films with Hybrid Alignment. Macromolecules 2010. [DOI: 10.1021/ma1003979] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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91
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Bitoh Y, Akuzawa N, Urayama K, Takigawa T. Strain energy function of swollen polybutadiene elastomers studied by general biaxial strain testing. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/polb.21945] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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92
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Urayama K. Electro-Opto-Mechanical Effects in Swollen Nematic Elastomers. LIQUID CRYSTAL ELASTOMERS: MATERIALS AND APPLICATIONS 2010. [DOI: 10.1007/12_2010_107] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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93
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Murata N, Konda A, Urayama K, Takigawa T, Kidowaki M, Ito K. Anomaly in Stretching-Induced Swelling of Slide-Ring Gels with Movable Cross-Links. Macromolecules 2009. [DOI: 10.1021/ma901661d] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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94
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Urayama K, Kohmon E, Kojima M, Takigawa T. Polydomain−Monodomain Transition of Randomly Disordered Nematic Elastomers with Different Cross-Linking Histories. Macromolecules 2009. [DOI: 10.1021/ma9004692] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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95
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Fukunaga A, Urayama K, Koelsch P, Takigawa T. Electrically driven director-rotation of swollen nematic elastomers as revealed by polarized Fourier transform infrared spectroscopy. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:051702. [PMID: 19518469 DOI: 10.1103/physreve.79.051702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Indexed: 05/27/2023]
Abstract
We have investigated the director reorientation behavior of unconstrained nematic gels (nematic elastomer swollen by low molecular mass liquid crystals) under electric fields by means of polarized Fourier transform infrared (FTIR) spectroscopy. The polarized FTIR reveals that the director rotates about the (y) axis normal to the original director ( x axis) and field directions ( z axis), and the nematic order remains unchanged in the plane where the director stays confined during rotation. The rotation angle of director (theta) is estimated as a function of imposed voltage amplitude on the basis of the absorbances of the cyano group which is aligned along the long axis of the mesogen for light linearly polarized in the x and y directions. The director-rotation drives a two-dimensional macroscopic deformation which is characterized by a contraction along the x axis, an extension in the z direction, and nonappreciable length change along the y axis. The strain in the x direction is linearly proportional to sin;{2} theta in agreement with the expectation of soft or semisoft elasticity theory for thin nematic elastomer films where the shear contribution becomes negligibly small.
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96
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Fukunaga A, Urayama K, Takigawa T, DeSimone A, Teresi L. Dynamics of Electro-Opto-Mechanical Effects in Swollen Nematic Elastomers. Macromolecules 2008. [DOI: 10.1021/ma801639j] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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97
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Urayama K, Dedeoglu DB, Guilini C, Frantz S, Ertl G, Messaddeq N, Nebigil CG. Transgenic myocardial overexpression of prokineticin receptor-2 (GPR73b) induces hypertrophy and capillary vessel leakage. Cardiovasc Res 2008; 81:28-37. [DOI: 10.1093/cvr/cvn251] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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98
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Urayama K, Taoka Y, Nakamura K, Takigawa T. Markedly compressible behaviors of gellan hydrogels in a constrained geometry at ultraslow strain rates. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.05.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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99
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100
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Nosaka S, Ishida T, Urayama K, Takigawa T. Steady flow properties of a mixed solvent through a poly(N-isopropylacrylamide) gel. J Memb Sci 2007. [DOI: 10.1016/j.memsci.2007.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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