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Folks WR, Keast S, Krentzel TA, Zalar B, Zeng H, Reznikov YA, Neubert M, Kumar S, Finotello D, Lavrentovich OD. Photocontrol of Smectic Spacing. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259808024385] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- W. R. Folks
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
- b Department of Physics , Kent State University , Kent , OH , 44242
| | - S. Keast
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
| | - T. A. Krentzel
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
| | - B. Zalar
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
| | - H. Zeng
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
| | - Yu. A. Reznikov
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
| | - M. Neubert
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
| | - S. Kumar
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
- b Department of Physics , Kent State University , Kent , OH , 44242
| | - D. Finotello
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
- b Department of Physics , Kent State University , Kent , OH , 44242
| | - O. D. Lavrentovich
- a Liquid Crystal Institute, Kent State University , Kent , OH , 44242
- c Chemical Physics Program, Kent State University , Kent , OH , 44242
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Bhatt NS, Zhang S, Keast SS, Neubert ME, Rosenblatt C. Velocity of an electric-field-induced synclinic solitary wave invading the anticlinic liquid crystal phase. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 63:062703. [PMID: 11415154 DOI: 10.1103/physreve.63.062703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2001] [Indexed: 05/23/2023]
Abstract
The electric-field dependence of the velocity of synclinic fingers invading the anticlinic phase is determined by a time-of-flight technique. The time delay for a rapid increase in the transmitted optical intensity through the sample is measured between two points as a function of their separation along the trajectory of the solitary wave. The data are quantitatively consistent with the rapid velocities deduced from a previous measurement [Liq. Cryst. 27, 249 (2000)], demonstrating that the previous data were not affected by multiple nucleation sites occurring at higher fields.
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Affiliation(s)
- N S Bhatt
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Wen B, Zhang S, Keast SS, Neubert ME, Taylor PL, Rosenblatt C. Freedericksz transition in an anticlinic liquid crystal. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 62:8152-8158. [PMID: 11138100 DOI: 10.1103/physreve.62.8152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2000] [Indexed: 05/23/2023]
Abstract
The Freedericksz geometry is used to show experimentally that a very-long-pitch, surface stabilized, anticlinic liquid crystal undergoes a two-step electric-field-induced transition to the synclinic phase. The liquid crystal remains undistorted below the threshold field E(th). For E>E(th), a Freedericksz transition occurs, wherein molecules in adjacent smectic layers undergo unequal azimuthal rotations about the layer normal, resulting in a nonzero polarization that couples to the applied field. Measurements of E(th) as a function of temperature are reported. Related quasielastic light scattering measurements demonstrate that acoustic Goldstone mode fluctuations are quenched by a dc electric field E>E(th). At high fields a transition to the synclinic phase occurs via solitary waves.
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Affiliation(s)
- B Wen
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Zhang S, Keast SS, Neubert ME, Petschek RG, Rosenblatt C. Electric field-induced acoustic-optic mode coupling in an anticlinic liquid crystal. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 62:R5911-R5914. [PMID: 11102013 DOI: 10.1103/physreve.62.r5911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2000] [Indexed: 05/23/2023]
Abstract
A dc electric field was applied perpendicular to the tilt plane of a pitch-compensated (unwound helix) anticlinic liquid crystal. By means of quasielastic light scattering, the field was found to couple the acoustic and optic Goldstone modes, resulting in an increase of the relaxation time tau(beta) of the acousticlike eigenmode. Elastic constants were estimated from the relaxation time data.
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Affiliation(s)
- S Zhang
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Link DR, Radzihovsky L, Natale G, Maclennan JE, Clark NA, Walsh M, Keast SS, Neubert ME. Ring-pattern dynamics in smectic-C* and smectic-C*A freely suspended liquid crystal films. Phys Rev Lett 2000; 84:5772-5775. [PMID: 10991051 DOI: 10.1103/physrevlett.84.5772] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/1999] [Indexed: 05/23/2023]
Abstract
Ring patterns of concentric 2pi solitons in molecular orientation form in freely suspended chiral smectic-C films in response to an in-plane rotating electric field. We present measurements of the driven dynamics of ring formation under conditions of synchronous winding and of the zero-field relaxation of ring patterns, and propose a simple model which enables their quantitative description in low polarization DOBAMBC. In smectic-C*A TFMHPOBC we observe an odd-even layer number effect, with odd layer number films exhibiting order of magnitude slower relaxation rates than even layer films. We show that this rate difference is due to a much larger spontaneous polarization in odd layer number films.
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Affiliation(s)
- D R Link
- Condensed Matter Laboratory, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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Zhang S, Wen B, Keast SS, Neubert ME, Taylor PL, Rosenblatt C. Freedericksz transition in an anticlinic liquid crystal. Phys Rev Lett 2000; 84:4140-4143. [PMID: 10990630 DOI: 10.1103/physrevlett.84.4140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2000] [Indexed: 05/23/2023]
Abstract
It is shown experimentally that a very-long-pitch, surface-stabilized, anticlinic liquid crystal undergoes a two-step electric-field-induced transition to the synclinic phase. The liquid crystal remains undistorted below a threshold field E(th). For E>E(th), a Freedericksz transition occurs, wherein molecules in adjacent smectic layers undergo unequal azimuthal rotations about the layer normal. At higher fields a transition to the synclinic phase occurs via solitary waves.
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Affiliation(s)
- S Zhang
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Patel P, Keast SS, Neubert ME, Kumar S. Nonexistence of incommensurate smectic-A phases in binary mixtures of 8OBCAB and DB8OCN. Phys Rev Lett 1992; 69:301-304. [PMID: 10046638 DOI: 10.1103/physrevlett.69.301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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