1
|
Nastishin Y, Savaryn V, Lychkovskyy E, Yakovlev MY, Vankevych P, Krupych O, Hrabchak V, Boiko O, Nazarenko V, Lavrentovich O. Effect of UV-light irradiation on phase diagram of lyotropic chromonic liquid crystal. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.12.079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
2
|
Bisoyi HK, Li Q. Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications. Chem Rev 2016; 116:15089-15166. [PMID: 27936632 DOI: 10.1021/acs.chemrev.6b00415] [Citation(s) in RCA: 400] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Light-driven phenomena both in living systems and nonliving materials have enabled truly fascinating and incredible dynamic architectures with terrific forms and functions. Recently, liquid crystalline materials endowed with photoresponsive capability have emerged as enticing systems. In this Review, we focus on the developments of light-driven liquid crystalline materials containing photochromic components over the past decade. Design and synthesis of photochromic liquid crystals (LCs), photoinduced phase transitions in LC, and photoalignment and photoorientation of LCs have been covered. Photomodulation of pitch, polarization, lattice constant and handedness inversion of chiral LCs is discussed. Light-driven phenomena and properties of liquid crystalline polymers, elastomers, and networks have also been analyzed. The applications of photoinduced phase transitions, photoalignment, photomodulation of chiral LCs, and photomobile polymers have been highlighted wherever appropriate. The combination of photochromism, liquid crystallinity, and fabrication techniques has enabled some fascinating functional materials which can be driven by ultraviolet, visible, and infrared light irradiation. Nanoscale particles have been incorporated to widen and diversify the scope of the light-driven liquid crystalline materials. The developed materials possess huge potential for applications in optics, photonics, adaptive materials, nanotechnology, etc. The challenges and opportunities in this area are discussed at the end of the Review.
Collapse
Affiliation(s)
- Hari Krishna Bisoyi
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University , Kent, Ohio 44242, United States
| | - Quan Li
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University , Kent, Ohio 44242, United States
| |
Collapse
|
3
|
Statman D, Statman AT, Wozniak K, Brennan C. Comparison of photoinduced reorientation of ortho-, meta-, and para-methyl red-doped nematic liquid crystals on rubbed polyimide. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:022503. [PMID: 26382419 DOI: 10.1103/physreve.92.022503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Indexed: 06/05/2023]
Abstract
We compare the photoinduced reorientation of the easy axis on rubbed polyimide surfaces for the nematic E7 doped with three isomers of methyl red; ortho, meta, and para. Using optical techniques, the angle and the pitch of the director at the polymer surface were measured before, during, and after photoexcitation of the dye. Optical absorbances were also measured before and after photoexcitation. Extrapolation lengths, hence anchoring energies, were determined with the on/off application of a magnetic field for meta- and para-methyl red-doped nematics. Because of an elastic reorientation of the easy axis in the presence of the magnetic field, we could not determine the extrapolation length of the ortho-methyl red-doped nematic. Our results confirm that photoinduced reorientation is facilitated by desorption of all dyes from the polymer surface. While there is little evidence of weak photoinduced adsorption of meta- and para-methyl red to the surface during photoexcitation, there is strong evidence of photoinduced adsorption of ortho-methyl red, which is long lasting.
Collapse
Affiliation(s)
- David Statman
- Physics Department and Chemistry Department, Allegheny College, Meadville, Pennsylvania 16335, USA
| | - Ariel T Statman
- Physics Department, Allegheny College, Meadville, Pennsylvania 16335, USA
| | - Kaitlin Wozniak
- Physics Department, Allegheny College, Meadville, Pennsylvania 16335, USA
| | | |
Collapse
|
4
|
Lucchetti L, Simoni F. Role of space charges on light-induced effects in nematic liquid crystals doped by methyl red. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:032507. [PMID: 24730864 DOI: 10.1103/physreve.89.032507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Indexed: 06/03/2023]
Abstract
We show that both the extraordinarily large nonlinear response and the light-induced permanent reorientation in liquid crystals doped by the azo dye methyl red originates from the same phenomenon of modification of the charge density on the irradiated surface. The demonstration is done by applying ac voltage to the samples, showing that in this case no permanent anchoring is possible. The measurements confirm the role of photoisomerization that gives a transient contribution to the actual reorientation process only in the high dose regime. This result allows us to draw a picture for light-induced effects that might be applied to a large class of compounds.
Collapse
Affiliation(s)
- L Lucchetti
- Dipartimento di Scienze e Ingegneria della Materia, dell'Ambiente ed Urbanistica and CNISM, Università Politecnica delle Marche, Ancona, Italy
| | - F Simoni
- Dipartimento di Scienze e Ingegneria della Materia, dell'Ambiente ed Urbanistica and CNISM, Università Politecnica delle Marche, Ancona, Italy
| |
Collapse
|
5
|
Saint-Jalm S, Miniewicz A, Karpinski P, Jarek-Mikulska U, Galewski Z. Photo-induced birefringence in a nematic liquid crystal mixture doped with light-switchable mesogenic azobenzene derivatives. J Mol Liq 2012. [DOI: 10.1016/j.molliq.2012.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
6
|
Yaroshchuk O, Reznikov Y. Photoalignment of liquid crystals: basics and current trends. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c1jm13485j] [Citation(s) in RCA: 403] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
7
|
Fuh AYG, Chen CC, Cheng KT, Liu CK, Chen WK. Polarization-independent holographic gratings based on azo-dye-doped polymer-dispersed liquid-crystal films. APPLIED OPTICS 2010; 49:275-280. [PMID: 20062516 DOI: 10.1364/ao.49.000275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We demonstrate polarization-independent holographic gratings (PIHGs) based on azo-dye-doped polymer-dispersed liquid crystal films. The PIHGs are recorded by irradiation under an intensity-modulated interference field, generated by two linearly polarized green optical beams, and by simultaneously applying a suitable AC voltage to the sample. The photoexcited azo dyes are adsorbed onto the UV-cured polymer film with their long axes parallel to the normal of the substrate. When the applied voltage is switched off, the PIHGs are generated with periodic modulation of liquid-crystal structures with transparently homeotropic and randomly scattered alignments. Additionally, the generated PIHGs can be completely switched off by an applied voltage.
Collapse
Affiliation(s)
- Andy Ying-Guey Fuh
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | | | | | | | | |
Collapse
|
8
|
Fuh AYG, Chen CC, Liu CK, Cheng KT. Polarizer-free, electrically switchable and optically rewritable displays based on dye-doped polymer-dispersed liquid crystals. OPTICS EXPRESS 2009; 17:7088-7094. [PMID: 19399084 DOI: 10.1364/oe.17.007088] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This work demonstrates the feasibility of a polarizer-free, electrically switchable and optically rewritable display based on dye-doped polymer-dispersed liquid crystals (DD-PDLCs). Experimental results indicate that the doped dyes are homeotropically adsorbed onto the polymer film when an appropriate AC voltage is applied during patterning. The adsorbed dyes in the illuminated region then align the liquid crystals homeotropically, and produce a transparent pattern in the scattering background without any polarizer. Notably, the adsorbed dyes can be erased and readsorbed using thermal and optical treatments, respectively. The switching time of the fabricated display is of the order of milliseconds, and the contrast ratio is approximately 30.
Collapse
Affiliation(s)
- Andy Ying-Guey Fuh
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | | | | | | |
Collapse
|
9
|
Lucchetti L, Gentili M, Simoni F, Pavliuchenko S, Subota S, Reshetnyak V. Surface-induced nonlinearities of liquid crystals driven by an electric field. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:061706. [PMID: 19256857 DOI: 10.1103/physreve.78.061706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Indexed: 05/27/2023]
Abstract
We report the study of the effect of a static electric field on the huge optical nonlinearity of methyl-red doped nematic liquid crystals. Experimental data are well fitted using a theoretical model that takes into account the modulation of the surface charge density due to the impinging light beam. It is demonstrated that the optical nonlinearity can be varied by orders of magnitude with application of a low voltage below the threshold of the Fredericks transition. These results confirm the previously proposed model of surface induced nonlinear effects.
Collapse
Affiliation(s)
- L Lucchetti
- Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio and CNISM, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
| | | | | | | | | | | |
Collapse
|
10
|
Fedorenko D, Slyusarenko K, Ouskova E, Reshetnyak V, Ha K, Karapinar R, Reznikov Y. Light-induced gliding of the easy orientation axis of a dye-doped nematic liquid crystal. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:061705. [PMID: 18643285 DOI: 10.1103/physreve.77.061705] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Indexed: 05/26/2023]
Abstract
We studied the effect of light-induced gliding of the easy axis of dye-doped nematic liquid crystal on an aligning polymer surface. The observed drift of the easy axis is over tens of degrees and is caused by light-induced anisotropic adsorption and/or desorption of dye molecules on or from the aligning layer in the presence of light-induced bulk torque. We present a theoretical model that explains the experimental data in terms of the light-induced changes of the adsorbed dye molecules angular distribution due to their exchange with the dye molecules from the liquid crystal bulk.
Collapse
Affiliation(s)
- Denis Fedorenko
- Institute of Physics, National Academy of Sciences of Ukraine, 46 Prospect Nauki, Kyiv, Ukraine.
| | | | | | | | | | | | | |
Collapse
|
11
|
Zola RS, Lenzi EK, Evangelista LR, Barbero G. Memory effect in the adsorption phenomena of neutral particles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:042601. [PMID: 17500940 DOI: 10.1103/physreve.75.042601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 12/21/2006] [Indexed: 05/15/2023]
Abstract
The adsorption-desorption phenomenon of neutral particles dissolved in an isotropic fluid is investigated by using a nonsingular kernel in the kinetic equation at the limiting surfaces. To account for the relevance of a memory effect, three types of kernels in the kinetic equation are considered. Similar kernels have been used to investigate nonexponential relaxation including several contexts such as dielectric relaxation, diffusion-controlled relaxation in liquids, liquid crystals, and amorphous polymers. A suitable choice for a temporal kernel can account for the relative importance of physisorption or chemisorption, according to the time scale governing the adsorption phenomena, and can be the key mechanism to understand the specific roles of both processes. By using a general procedure, the time evolution of the density of particles is determined in closed analytical form. The analysis is relevant in the description of the adsorption phenomena in general.
Collapse
Affiliation(s)
- R S Zola
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020-900 Maringá, Paraná, Brazil
| | | | | | | |
Collapse
|
12
|
Alexe-Ionescu AL, Uncheselu C, Lucchetti L, Barbero G. Phenomenological model for the optically induced easy direction. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:021701. [PMID: 17358354 DOI: 10.1103/physreve.75.021701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 11/13/2006] [Indexed: 05/14/2023]
Abstract
We present a phenomenological model to interprete the optically induced easy direction in a nematic cell in the slab approximation. One of the surfaces of the sample is supposed to give strong anchoring, whereas the other, covered with photosensible material, very weak anchoring. We assume that a surface nematic molecule is submitted to a potential connected with its interaction with the surface easy direction, with the surface nematic field, and with the optical induced anisotropy. The case in which the coupling with the nematic order in the bulk is important is considered too. A differential equation for the time evolution of the surface director is proposed, in which the viscous torque is balanced by the torque related to the surface fields. We show that our theoretical predictions are in agreement with experimental data on the optical induced surface orientation. The dependence of the anchoring energy strength on the irradiation time for dye-doped liquid crystals is also investigated.
Collapse
Affiliation(s)
- A L Alexe-Ionescu
- Departamentul de Fizica, Universitatea Politehnica din Bucuresti, Splaiul Independentei 313, Ro-060042 Bucharest, Romania
| | | | | | | |
Collapse
|