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Wu Y, Zou C, Shi Y, Song Z, Xiao J, Yu M, Gao Y, Wang Q, Yang H. Reverse-Mode Polymer-Stabilized Liquid Crystal Films with Enhanced Peel Strength and Electro-Optical Performance Based on Photoreactive Self-Assembly Alignment Layers and Patterned Polymer Walls. ACS APPLIED MATERIALS & INTERFACES 2024; 16:40046-40055. [PMID: 39025782 DOI: 10.1021/acsami.4c08934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Polymer-stabilized liquid crystal (PSLC) is a promising material toward the practical application of serving as energy-saving reverse-mode smart windows owing to its superior electro-optical (E-O) properties, simple and efficient processability, and compatibility to most practical circumstances. However, its feeble peel strength originated from low polymer content and poor adhesion between polymer networks and substrates inhibited its large-scale flexible film production. It is still a challenging task to derive good mechanical properties and superior E-O performance for PSLCs at the same time. In this study, a highly durable liquid crystal/polymer composite film showing enhanced peel strength and excellent E-O properties was attained by simultaneously building photoreactive self-assemble alignment layers through an efficient one-step method and the sculpture of a patterned polymer wall structure. This film has comprehensive ascendant E-O properties of lower driving voltages, faster response times, and higher contrast ratio, together with an over 30 times lift of the peel strength. The effectuation mechanisms of the alignment, E-O properties, peel-strength, microstructures, and cyclic durability of the films have been systematically studied. This novel liquid crystal/polymer composite film demonstrates advantages in every aspect of performance compared to traditional PSLC devices, which hoards promising applications in smart windows for cars and buildings.
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Affiliation(s)
- Yishuo Wu
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Cheng Zou
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Yingjie Shi
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhexu Song
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Jiumei Xiao
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Meina Yu
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanzi Gao
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Qian Wang
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Huai Yang
- School of Materials Science and Engineering, Peking University, Beijing 100083, China
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2
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Kawakami C, Hara M, Nagano S, Seki T. Induction of Highly Ordered Liquid Crystalline Phase of an Azobenzene Side Chain Polymer by Contact with 4'-Pentyl-4-cyanobiphenyl: An In Situ Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:619-626. [PMID: 36545757 DOI: 10.1021/acs.langmuir.2c02950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The orientation of liquid crystal (LC) molecules is significantly governed by solid interfaces and free surfaces, and a variety of functional materials have been developed using these properties. Although LC materials are already in industrial use, particularly for LC display panels, various studies have been conducted in recent years to better grasp the interface behavior of LC molecules. In this work, we succeeded in in situ observations of induction of higher ordered LC phases at the interface between a side-chain LC azobenzene polymer film with a thickness of ∼400 nm and a low-molecular-mass nematic LC, 4'-pentyl-4-cyanobiphenyl of 35 μm thickness, using small-angle X-ray scattering measurements and polarized optical microscopy. It is revealed that the two different mesogens cooperatively form hybrid higher ordered smectic LC phases probably through weak electron transfer immediately after interfacial contact. The induction process consists of three stages in terms of dynamic structure evolutions. Upon UV irradiation, the hybrid smectic LC structure diminished. This study provides new insights into the behavior of LC molecules near the alignment film on the solid substrate.
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Affiliation(s)
- Chikara Kawakami
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Mitsuo Hara
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Shusaku Nagano
- Department of Chemistry, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan
| | - Takahiro Seki
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
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3
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Park K, Hyeon S, Kang KM, Eum K, Kim J, Kim DW, Jung HT. Long-Range alignment of liquid crystalline small molecules on Metal-Organic framework micropores by physical anchoring. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2021.09.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Template-assisted interfacial self-assembly of amphiphilic poly(ethylene oxide)–poly(propylene oxide)-based triblock copolymers for automatic control of molecular alignment. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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5
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Zhang Y, Yang W, Gu M, Wei Q, Lv P, Li M, Liu D, Zhao W, Broer DJ, Zhou G. Versatile homeotropic liquid crystal alignment with tunable functionality prepared by one-step method. J Colloid Interface Sci 2021; 608:2290-2297. [PMID: 34774317 DOI: 10.1016/j.jcis.2021.10.159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/18/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022]
Abstract
Alignment layers are vital to the function of numerous devices based on liquid crystal (LC) materials. The pursue of versatile, effective and even flexible alignment layers, preferably prepared by simple methods, is still actively ongoing. Herein, we propose a facile one-step method by mixing silanes into the starting LC mixtures, which in contact with a glass substrate secede and self-assemble in-situ to form a stable and highly effective homeotropic alignment layer at the interface. Tetradecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride (TDTA) is selected as the example to demonstrate the method, although a number of other silanes can produce similar results. With only 0.05 vol% of TDTA added to a mixture of liquid crystals and reactive mesogens, a uniform monolayer is chemically attached to the substrate, which automatically aligns the LCs homeotropically. Furthermore, by blending the TDTA with acrylate functionalized silanes like 3-(trimethoxysilyl)propyl methacrylate (A174), additional reactive functional groups can be easily introduced into the alignment layer, therefore offering opportunities to adjust the interface properties. An electro-responsive smart window based on the polymer stabilized liquid crystals (PSLCs) is successfully prepared using a one-step method, demonstrating excellent electro-optic performances and notably enhanced adhesion between the substrate and the in-situ formed polymer network. These findings are valuable especially for the development of flexible LC devices.
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Affiliation(s)
- Yang Zhang
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China; Solar Energy Research Institute, Yunnan Normal University, Kunming 650500, China
| | - Weiping Yang
- Solar Energy Research Institute, Yunnan Normal University, Kunming 650500, China
| | - Minzhao Gu
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China
| | - Qunmei Wei
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China
| | - Pengrong Lv
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China
| | - Ming Li
- Solar Energy Research Institute, Yunnan Normal University, Kunming 650500, China.
| | - Danqing Liu
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China; Stimuli-responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, Eindhoven 5600 MB, the Netherlands
| | - Wei Zhao
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China; Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
| | - Dirk J Broer
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China; Stimuli-responsive Functional Materials and Devices, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, Eindhoven 5600 MB, the Netherlands
| | - Guofu Zhou
- SCNU-TUE Joint Lab of Device Integrated Responsive Materials (DIRM), National Center for International Research on Green Optoelectronics, South China Normal University, No 378, West Waihuan Road, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China; Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; Shenzhen Guohua Optoelectronics Tech. Co. Ltd., Shenzhen 518110, China
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6
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Son I, Son SR, An J, Choi JW, Kim S, Lee WY, Lee JH. Photoluminescent surface-functionalized graphene quantum dots for spontaneous interfacial homeotropic orientation of liquid crystals. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115901] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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Zhou L, Su Q, Wu F, Wan Y, Xu P, Dong A, Li Q, Qian W. Using Reflectometric Interference Spectroscopy to Real-Time Monitor Amphiphile-Induced Orientational Responses of Liquid-Crystal-Loaded Silica Colloidal Crystal Films. Anal Chem 2020; 92:12071-12078. [DOI: 10.1021/acs.analchem.0c02749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lele Zhou
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Qianqian Su
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Feng Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yizhen Wan
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Pengfei Xu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Ao Dong
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Qiang Li
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Weiping Qian
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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8
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Hinckley AP, Muscat AJ. Detecting and Removing Defects in Organosilane Self-Assembled Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:2563-2573. [PMID: 32097555 DOI: 10.1021/acs.langmuir.9b02753] [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
Defects occur as self-assembled monolayers form, and the number and type of defects depend on the surface preparation and deposition solvent, among other parameters. Indirect measures to detect defects using a layer property, such as the thickness or bond vibrational frequency, are used routinely for process development but often lack sensitivity. Direct measures using an atomic probe offer a glimpse of defect structures but over a small fraction of the layer. Direct detection after reacting defects by etching or deposition is more common, and this approach has advanced our understanding of how monolayers form and has led to improved monolayers for a variety of applications. Here we show that a series of TiCl4 gas pulses reacts with defects in organosilane layers on SiO2 depositing TiO, which was measured by X-ray photoelectron spectroscopy. The defects were silanol groups and siloxane bridge bonds at the interface between the layer and the SiO2 surface and on agglomerates physisorbed to the layer. As the TiO saturation coverage or the total number of defects decreased, the incubation period in which no TiO was detected became longer. Cleaning the layer by solvent extraction to remove nonpolar agglomerates followed by an aqueous mixture of ammonium hydroxide and hydrogen peroxide, which is Standard Clean 1, a common particle removal step for silicon surfaces, produced an organosilane monolayer without agglomerates based on atomic force microscopy. After a second organosilane immersion, the monolayer density rose to 3.8 molecules/nm2. This monolayer inhibited the deposition of TiO on the SiO2 surface for 250 pulses of TiCl4 and 200 complete TiO2 atomic layer deposition cycles using TiCl4 and water vapor, and it failed at 300 complete cycles. The Standard Clean 1 solution not only removed defects left by solvent extraction but also led to the reorganization of the organosilane layer.
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Affiliation(s)
- Adam P Hinckley
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Anthony J Muscat
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States
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9
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Chinky, Kumar P, Sharma V, Malik P, Raina K. Nano particles induced vertical alignment of liquid crystal for display devices with augmented morphological and electro-optical characteristics. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.06.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Wang S, Zhang G, Chen Q, Zhou J, Wu Z. Sensing of cocaine using polarized optical microscopy by exploiting the conformational changes of an aptamer at the water/liquid crystal interface. Mikrochim Acta 2019; 186:724. [DOI: 10.1007/s00604-019-3855-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 09/19/2019] [Indexed: 11/29/2022]
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11
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Yanagimachi T, Li X, Nealey PF, Kurihara K. Surface anchoring of nematic liquid crystal on swollen polymer brush studied by surface forces measurement. Adv Colloid Interface Sci 2019; 272:101997. [PMID: 31421457 DOI: 10.1016/j.cis.2019.101997] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/08/2019] [Accepted: 07/30/2019] [Indexed: 11/25/2022]
Abstract
Surface anchoring plays a fundamental role in controlling the molecular alignment of a bulk liquid crystal (LC). It has been previously shown that the pretilt angle of a nematic liquid crystal (NLC) can be controlled by changing the grafting density of a liquid crystalline polymer, poly(6-(4-methoxy-azobenzene-4'-oxy) hexyl methacrylate) (PMMAZO). In this study, the thickness of the swollen PMMAZO brush was measured by employing the surface forces apparatus (SFA). NLC 4-cyano-4'-pentylbiphenyl (5CB) and toluene were used as the solvents. It was shown that both 5CB and toluene were good solvents for PMMAZO. The repulsive force in 5CB appeared at D0 = 98.2 ± 4.6 nm for high grafting density (HD) surfaces, and at 32.1 ± 4.5 nm for the low grafting density (LD) surfaces. These results indicated that the PMMAZO molecules extended nearly perpendicular to the HD surfaces, while they laid on the substrate for the LD surfaces. The interaction between 5CB and the mesogenic group of PMMAZO was stronger than that for toluene. These results could support the expected surface anchoring mechanism of 5CB by the PMMAZO brush.
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12
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Filarsky F, Schmuck C, Schultz HJ. Impact of Modified Silica Beads on Methane Hydrate Formation in a Fixed-Bed Reactor. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b01952] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Florian Filarsky
- Institute of Organic Chemistry, Chair of Organic Chemistry, University of Duisburg-Essen, Universitätsstr. 7, 45141 Essen, Germany
- Faculty of Chemistry, Chemical Engineering, University of Applied Sciences Niederrhein, Adlerstr. 32, 47798 Krefeld, Germany
| | - Carsten Schmuck
- Institute of Organic Chemistry, Chair of Organic Chemistry, University of Duisburg-Essen, Universitätsstr. 7, 45141 Essen, Germany
| | - Heyko Juergen Schultz
- Faculty of Chemistry, Chemical Engineering, University of Applied Sciences Niederrhein, Adlerstr. 32, 47798 Krefeld, Germany
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13
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Traeger JC, Lamberty Z, Schwartz DK. Influence of Oligonucleotide Grafting Density on Surface-Mediated DNA Transport and Hybridization. ACS NANO 2019; 13:7850-7859. [PMID: 31244029 DOI: 10.1021/acsnano.9b02157] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Adsorption of soluble DNA to surfaces decorated with complementary DNA plays an important role in many bionanotechnology applications, and previous studies have reported complex dependencies of the surface density of immobilized DNA on hybridization. While these effects have been speculatively ascribed to steric or electrostatic effects, the influence of surface-mediated molecular transport (i.e., intermittent "hopping diffusion") has not been fully appreciated. Here, single-molecule tracking and Förster resonance energy transfer (FRET) were employed to characterize the mobility and the hybridization efficiency of adsorbed ssDNA oligonucleotides ("target") at solid-liquid interfaces exhibiting surface-immobilized ssDNA ("probe") over a wide range of surface grafting densities. Two distinct regimes were observed, with qualitatively different transport and hybridization behaviors. At dilute grafting density, only 1-3% of target molecules were observed to associate with probes (i.e., to hybridize). Adsorbing target molecules often searched unsuccessfully and "flew", via desorption-mediated diffusion, to secondary locations before hybridizing. In contrast, at high probe grafting density, approximately 20% of target DNA hybridized to immobilized probes, and almost always in the vicinity of initial adsorption. Moreover, following a dehybridization event, target molecules rehybridized at high probe density, but rehybridization was infrequent in the dilute density regime. Interestingly, the intermittent interfacial transport of mobile target molecules was suppressed by the presence of immobilized probe DNA, presumably due to an increased probability of readsorption following each "hop". Together, these findings suggested that many salient effects of grafting density on surface-mediated DNA hybridization can be directly related to the mechanisms of surface-mediated intermittent diffusion.
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Affiliation(s)
- Jeremiah C Traeger
- Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | - Zachary Lamberty
- Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States
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14
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Mukai K, Imai K, Hara M, Nagano S, Seki T. A High‐Density Azobenzene Side Chain Polymer Brush for Azimuthal and Zenithal Orientational Photoswitching of a Nematic Liquid Crystal. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201800234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Koji Mukai
- Department of Molecular and Macromolecular ChemistryGraduate School of Engineering, Nagoya University Furo-cho, Chikusa Nagoya 464-8603 Japan
| | - Kenjiro Imai
- Department of Molecular and Macromolecular ChemistryGraduate School of Engineering, Nagoya University Furo-cho, Chikusa Nagoya 464-8603 Japan
| | - Mitsuo Hara
- Department of Molecular and Macromolecular ChemistryGraduate School of Engineering, Nagoya University Furo-cho, Chikusa Nagoya 464-8603 Japan
| | - Shusaku Nagano
- Nagoya University Venture Business Laboratory Furo-cho, Chikusa Nagoya 464-8603 Japan
| | - Takahiro Seki
- Department of Molecular and Macromolecular ChemistryGraduate School of Engineering, Nagoya University Furo-cho, Chikusa Nagoya 464-8603 Japan
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15
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Li X, Yanagimachi T, Bishop C, Smith C, Dolejsi M, Xie H, Kurihara K, Nealey PF. Engineering the anchoring behavior of nematic liquid crystals on a solid surface by varying the density of liquid crystalline polymer brushes. SOFT MATTER 2018; 14:7569-7577. [PMID: 30065982 DOI: 10.1039/c8sm00991k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controlling the orientation of liquid crystal (LC) molecules towards contacting surfaces is a crucial requirement for the development of LC displays and passive electro-optical devices. Up to now, research has been focused on photo-responses of a LC azobenzene polymer system to obtain either planar or homeotropic orientation of LCs. It remains a challenge, however, to tune the polar angle of LC molecules on the solid surface and gain more insights about the polymer chain conformation extending in LC medium. Here, we deposit a liquid crystalline side chain polymer brush, poly(6-(4-methoxy-azobenzene-4'-oxy)hexyl methacrylate) (PMMAZO), onto the solid surface with film thickness varying between ∼3 nm and 13 nm; therefore, the grafting density of the brush layer ranges from 0.0219 to 0.0924 chains per nm2. When LCs are confined in hybrid cells with a top surface eliciting uniform homeotropic anchoring and a bottom surface covered by the PMMAZO brush, the out-of-plane polar angle of 4-pentyl-4'-cyanobiphenyl (5CB) on the brush layer gradually changes from ∼0° to ∼62° by simply increasing the grafting brush density. The surface forces apparatus (SFA) measurement is used to determine 5CB as a good solvent for the PMMAZO brush and understand the relationship between the chain conformation in 5CB and the anchoring behavior of LC molecules on the polymer brush layer. For high grafting density, the polymer chain in 5CB extends significantly away from the substrate, making the side chain mesogens on average almost parallel to the substrate; for the low-density case, the main chain extends in the narrow region around the surface for aligning the mesogens perpendicular to the substrate.
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Affiliation(s)
- Xiao Li
- Institute for Molecular Engineering, University of Chicago, Chicago, USA.
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16
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Jones SA, Bailey J, Walker DRE, Bryan-Brown GP, Jones JC. Method for Tuneable Homeotropic Anchoring at Microstructures in Liquid Crystal Devices. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10865-10873. [PMID: 30132669 DOI: 10.1021/acs.langmuir.8b01951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A simple method for vapour-phase deposition of a silane surfactant is presented, which produces tuneable homeotropic anchoring in liquid crystals. Both the zenithal anchoring energy and surface slip are measured by fitting to the latching threshold versus pulse width characteristic of a zenithal bistable nematic liquid crystal device based on a deep, submicron grating. The method is shown to give microscopic anchoring strength between 5 × 10-5 and 2 × 10-4 J/m2, with a surface slip of about 100 nm. The silanated surfaces are characterized using atomic force microscopy and X-ray photoelectron spectroscopy, which show a direct relationship between the surface coverage of silane groups and the resulting anchoring energy.
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Affiliation(s)
- Sophie A Jones
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , U.K
| | - James Bailey
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , U.K
- Dynamic Vision Systems , Leeds Innovation Centre , 103 Clarendon Road , Leeds LS2 9DF , U.K
| | - David R E Walker
- DisplayData Limited , Malvern Hills Science Park , Malvern , Worcstershire WR13 5SZ , U.K
| | - Guy P Bryan-Brown
- DisplayData Limited , Malvern Hills Science Park , Malvern , Worcstershire WR13 5SZ , U.K
| | - J Cliff Jones
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , U.K
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17
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Sivaranjini B, Mangaiyarkarasi R, Ganesh V, Umadevi S. Vertical Alignment of Liquid Crystals Over a Functionalized Flexible Substrate. Sci Rep 2018; 8:8891. [PMID: 29891908 PMCID: PMC5995910 DOI: 10.1038/s41598-018-27039-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/14/2018] [Indexed: 12/03/2022] Open
Abstract
A simple and effective approach for vertical alignment of liquid crystals (LCs) over a functionalized transparent flexible substrate is described. Surface characterization of this commercially available plastic substrate through X-ray photoelectron spectroscopy (XPS) and attenuated total reflection infrared spectroscopy (ATR-IR) indicated that cellulose acetate is main component of the transparent substrate. This substrate was chemically functionalized with a suitable LC compound. A trimethoxysilane terminated new rod-shaped mesogen is synthesized and covalently attached to the pre-treated film through silane condensation reaction. LC functionalization of the polymer film is confirmed through contact angle (CA), atomic force microscopy (AFM), XPS and ATR-IR spectroscopy studies. Versatility of the LC modified flexible substrates for the alignment of bulk LC sample at substrate-LC interface was assessed for nematic (N) and smectic A (SmA) phases. Remarkably, LC functionalized cellulose acetate films were found to be highly efficient in assisting a perfect homeotropic alignment of LCs (for both, a room temperature N and a high temperature SmA phase) over the entire area of the LC sample under observation indicating their superior aligning ability in comparison to their unmodified and octadecyltrimethoxysilane (OTS) modified counterparts. The demonstrated method of surface modification of flexible polymer film is easy, surface modified substrates are stable for several months, retained their aligning ability intact and more importantly they are reusable with maximum delivery.
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Affiliation(s)
- B Sivaranjini
- Department of Industrial Chemistry, Alagappa University, Karaikudi, 630003, India
| | - R Mangaiyarkarasi
- Department of Industrial Chemistry, Alagappa University, Karaikudi, 630003, India
| | - V Ganesh
- Electrodics and Electrocatalysis Division (EEC), CSIR - Central Electrochemical Research Institute (CSIR-CECRI), Karaikudi, 630003, India
| | - S Umadevi
- Department of Industrial Chemistry, Alagappa University, Karaikudi, 630003, India.
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Oswald P, Ignés-Mullol J. Modeling a photoinduced planar-to-homeotropic anchoring transition triggered by surface azobenzene units in a nematic liquid crystal. Phys Rev E 2017; 96:032704. [PMID: 29347016 DOI: 10.1103/physreve.96.032704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Indexed: 06/07/2023]
Abstract
The performance of light-controlled liquid crystal anchoring surfaces depends on the nature of the photosensitive moieties and on the concentration of spacer units. Here, we study the kinetics of photosensitive liquid crystal cells that incorporate an azobenzene-based self-assembled monolayer. We characterize the photoinduced homeotropic-to-planar transition and the subsequent reverse relaxation in terms of the underlying isomerization of the photosensitive layer. We show that the response time can be precisely adjusted by tuning the lateral packing of azobenzene units by means of inert spacer molecules. Using simple kinetic assumptions and a well-known model for the energetics of liquid crystal anchoring we are able to capture the details of the optical microscopy experimental observations. Our analysis provides fitted values for all the relevant material parameters, including the zenithal and the azimuthal anchoring strength.
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Affiliation(s)
- Patrick Oswald
- Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Jordi Ignés-Mullol
- Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique, F-69342 Lyon, France
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
- Departament de Ciència de Materials i Química Física, Universitat de Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain
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19
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Roscioni OM, Muccioli L, Zannoni C. Predicting the Conditions for Homeotropic Anchoring of Liquid Crystals at a Soft Surface. 4-n-Pentyl-4'-cyanobiphenyl on Alkylsilane Self-Assembled Monolayers. ACS APPLIED MATERIALS & INTERFACES 2017; 9:11993-12002. [PMID: 28287693 DOI: 10.1021/acsami.6b16438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have studied, using atomistic molecular dynamics simulations, the alignment of the nematic liquid-crystal 4-n-pentyl-4'-cyanobiphenyl (5CB) on self-assembled monolayers (SAMs) formed from octadecyl- and/or hexyltrichlorosilane (OTS and HTS) attached to glassy silica. We find a planar alignment on OTS at full coverage and an intermediate situation at partial OTS coverage because of the penetration of 5CB molecules into the monolayer, which also removes the tilt of the OTS SAM. Binary mixtures of HTS and OTS SAMs instead induce homeotropic (i.e., perpendicular) alignment. A comparison with the existing experimental literature is provided.
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Affiliation(s)
- Otello Maria Roscioni
- Dipartimento di Chimica Industriale "Toso Montanari" Università di Bologna , viale Risorgimento 4, IT-40136 Bologna, Italy
| | - Luca Muccioli
- Dipartimento di Chimica Industriale "Toso Montanari" Università di Bologna , viale Risorgimento 4, IT-40136 Bologna, Italy
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" Università di Bologna , viale Risorgimento 4, IT-40136 Bologna, Italy
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20
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Macri KM, Noonan PS, Schwartz DK. Receptor-Mediated Liposome Fusion Kinetics at Aqueous/Liquid Crystal Interfaces. ACS APPLIED MATERIALS & INTERFACES 2015; 7:20400-20409. [PMID: 26317496 DOI: 10.1021/acsami.5b06351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Membrane fusion events are essential to cell biology, and a number of reductionist systems have been developed to mimic the behavior of these biological motifs. One such system monitors the DNA hybridization-mediated fusion of liposomes with the liquid crystal (LC) interface by observing changes in LC orientation using a simple optical detection scheme. We have systematically explored key parameters of this system to determine their effects on individual elementary steps of the complex fusion mechanism. The liposome composition, specifically the degree of lipid unsaturation and PE content, decreased the bilayer rigidity, thereby increasing the rate of vesicle rupture under the stress applied by DNA hybridization. In contrast, the presence of cholesterol had the opposite effect on the mechanical properties of the bilayer, and hence of the membrane fusion rates. The accessibility of receptor moieties (i.e., complementary DNA oligonucleotides) affected the fusion kinetics by modulating the rate of hybridization events. DNA accessibility was controlled by systematic variation of the length of the DNA receptor molecules and the thickness of the steric barrier comprised of adsorbed PEGylated lipids. These results provide design rules for understanding the trade-offs between response kinetics and other important system properties, such as nonspecific adsorption. Moreover, these findings improve our understanding of the biophysical properties of membrane fusion, an important process in both natural and model systems used for bioassay and bioimaging applications.
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Affiliation(s)
- Katherine M Macri
- Department of Chemical and Biological Engineering, University of Colorado Boulder , Boulder, Colorado 80309-0596, United States
| | - Patrick S Noonan
- Department of Chemical and Biological Engineering, University of Colorado Boulder , Boulder, Colorado 80309-0596, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder , Boulder, Colorado 80309-0596, United States
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21
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Kim DY, Lee SA, Kang DG, Park M, Choi YJ, Jeong KU. Photoresponsive carbohydrate-based giant surfactants: automatic vertical alignment of nematic liquid crystal for the remote-controllable optical device. ACS APPLIED MATERIALS & INTERFACES 2015; 7:6195-6204. [PMID: 25738306 DOI: 10.1021/acsami.5b00259] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Photoresponsive carbohydrate-based giant surfactants (abbreviated as CELAnD-OH) were specifically designed and synthesized for the automatic vertical alignment (VA) layer of nematic (N) liquid crystal (LC), which can be applied for the fabrication of remote-controllable optical devices. Without the conventional polymer-based LC alignment process, a perfect VA layer was automatically constructed by directly adding the 0.1 wt % CELA1D-OH in the N-LC media. The programmed CELA1D-OH giant surfactants in the N-LC media gradually diffused onto the substrates of LC cell and self-assembled to the expanded monolayer structure, which can provide enough empty spaces for N-LC molecules to crawl into the empty zones for the construction of VA layer. On the other hand, the CELA3D-OH giant surfactants forming the condensed monolayer structure on the substrates exhibited a planar alignment (PA) rather than a VA. Upon tuning the wavelength of light, the N-LC alignments were reversibly switched between VA and PA in the remote-controllable LC optical devices. Based on the experimental results, it was realized that understanding the interactions between N-LC molecules and amphiphilic giant surfactants is critical to design the suitable materials for the automatic LC alignment.
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22
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Li L, Garde S. Binding, structure, and dynamics of hydrophobic polymers near patterned self-assembled monolayer surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:14204-14211. [PMID: 25337813 DOI: 10.1021/la503537b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We use molecular dynamics simulations to study the binding, conformations, and dynamics of a flexible 25-mer hydrophobic polymer near well-defined patterned self-assembled monolayers containing a hydrophobic strip (with -CH3 head-groups) having different widths in a hydrophilic (-OH) background. We show that the polymer binds favorably to hydrophobic strips of all widths, including the subnanometer ones comprising 3, 2, or even 1 row of -CH3 head-groups, with the binding strength varying from about 107 to 25 kJ/mol for the widest to the narrowest strip. Near wide hydrophobic patches containing 5 or more -CH3 rows, pancakelike conformations are dominant, whereas hairpinlike structures become preferred ones near the narrower strips. In the vicinity of the narrowest 1-row strip, the polymer folds into semiglobular conformations, thus maintaining sufficient contact with the strip while sequestering its hydrophobic groups away from water. We also show that the confinement makes the translational dynamics of the polymer anisotropic as well as conformational dependent. Our results may help to understand and manipulate the self-assembly and dynamics of soft matter, such as polymers, peptides, and proteins, at inhomogeneous patterned surfaces.
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Affiliation(s)
- Lijuan Li
- The Howard P. Isermann Department of Chemical and Biological Engineering and The Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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23
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Ishida T, Oyama M, Terada KI, Haga MA. Dynamic pattern formation of liquid crystals using binary self-assembled monolayers on an ITO surface under DC voltage. Phys Chem Chem Phys 2014; 16:25008-13. [DOI: 10.1039/c4cp03622k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Noonan PS, Mohan P, Goodwin AP, Schwartz DK. DNA Hybridization-Mediated Liposome Fusion at the Aqueous Liquid Crystal Interface. ADVANCED FUNCTIONAL MATERIALS 2014; 24:3206-3212. [PMID: 25506314 PMCID: PMC4262931 DOI: 10.1002/adfm.201303885] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The prominence of receptor-mediated bilayer fusion in cellular biology motivates development of biomimetic strategies for studying fusogenic mechanisms. An approach is reported here for monitoring receptor-mediated fusion that exploits the unique physical and optical properties of liquid crystals (LC). PEG-functionalized lipids are used to create an interfacial environment capable of inhibiting spontaneous liposome fusion with an aqueous/LC interface. Then, DNA hybridization between oligonucleotides within bulk phase liposomes and a PEG-lipid monolayer at an aqueous/LC interface is exploited to induce receptor-mediated liposome fusion. These hybridization events induce strain within the liposome bilayer, promote lipid mixing with the LC interface, and consequently create an interfacial environment favoring re-orientation of the LC to a homeotropic (perpendicular) state. Furthermore, the bi-functionality of aptamers is exploited to modulate DNA hybridization-mediated liposome fusion by regulating the availability of the appropriate ligand (i.e., thrombin). Here, a LC-based approach for monitoring receptor (i.e., DNA hybridization)-mediated liposome fusion is demonstrated, liposome properties that dictate fusion dynamics are explored, and an example of how this approach may be used in a biosensing scheme is provided.
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Affiliation(s)
- Patrick S. Noonan
- Department of Chemical and Biological Engineering University of Colorado Boulder Boulder, CO 80309–0424
| | - Praveena Mohan
- Department of Chemical and Biological Engineering University of Colorado Boulder Boulder, CO 80309–0424
| | - Andrew P. Goodwin
- Department of Chemical and Biological Engineering University of Colorado Boulder Boulder, CO 80309–0424
| | - Daniel K. Schwartz
- Department of Chemical and Biological Engineering University of Colorado Boulder Boulder, CO 80309–0424
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25
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Nguyen TD, Carrillo JMY, Matheson MA, Brown WM. Rupture mechanism of liquid crystal thin films realized by large-scale molecular simulations. NANOSCALE 2014; 6:3083-3096. [PMID: 24264516 DOI: 10.1039/c3nr05413f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The ability of liquid crystal (LC) molecules to respond to changes in their environment makes them an interesting candidate for thin film applications, particularly in bio-sensing, bio-mimicking devices, and optics. Yet the understanding of the (in)stability of this family of thin films has been limited by the inherent challenges encountered by experiment and continuum models. Using unprecedented large-scale molecular dynamics (MD) simulations, we address the rupture origin of LC thin films wetting a solid substrate at length scales similar to those in experiment. Our simulations show the key signatures of spinodal instability in isotropic and nematic films on top of thermal nucleation, and importantly, for the first time, evidence of a common rupture mechanism independent of initial thickness and LC orientational ordering. We further demonstrate that the primary driving force for rupture is closely related to the tendency of the LC mesogens to recover their local environment in the bulk state. Our study not only provides new insights into the rupture mechanism of liquid crystal films, but also sets the stage for future investigations of thin film systems using peta-scale molecular dynamics simulations.
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Affiliation(s)
- Trung Dac Nguyen
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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26
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Upadhyay AP, Sadhukhan P, Roy S, Ganesh S Pala R, Sivakumar S. Brownian motion retarded polymer-encapsulated liquid crystal droplets anchored over a patterned substrate via click chemistry. RSC Adv 2014. [DOI: 10.1039/c4ra02734e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Formation of a five-membered strong triazole ring to facilitate the highly stable anchoring of LC droplet encapsulated polymer capsules over a patterned substrate.
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Affiliation(s)
| | - Prasenjit Sadhukhan
- Department of Chemical Engineering
- Indian Institute of Technology
- Kanpur, India
| | - Sudeshna Roy
- DST Unit of Soft Nanofabrication
- Indian Institute of Technology Kanpur
- Kanpur, India
| | - Raj Ganesh S Pala
- Department of Chemical Engineering
- Indian Institute of Technology
- Kanpur, India
| | - Sri Sivakumar
- Department of Chemical Engineering
- Indian Institute of Technology
- Kanpur, India
- DST Unit of Soft Nanofabrication
- Indian Institute of Technology Kanpur
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27
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Effect of molecular structure and packing density of an azo self-assembled monolayer on liquid crystal alignment. J Colloid Interface Sci 2013; 407:310-7. [DOI: 10.1016/j.jcis.2013.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 06/01/2013] [Accepted: 06/06/2013] [Indexed: 11/19/2022]
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28
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Noonan PS, Roberts RH, Schwartz DK. Liquid Crystal Reorientation Induced by Aptamer Conformational Changes. J Am Chem Soc 2013; 135:5183-9. [DOI: 10.1021/ja400619k] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Patrick S. Noonan
- Department of Chemical
and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309-0424,
United States
| | - Richard H. Roberts
- Department of Chemical
and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309-0424,
United States
| | - Daniel K. Schwartz
- Department of Chemical
and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309-0424,
United States
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29
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30
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Liu Y, Cheng D, Lin IH, Abbott NL, Jiang H. Microfluidic sensing devices employing in situ-formed liquid crystal thin film for detection of biochemical interactions. LAB ON A CHIP 2012; 12:3746-53. [PMID: 22842797 PMCID: PMC3448960 DOI: 10.1039/c2lc40462a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Although biochemical sensing using liquid crystals (LC) has been demonstrated, relatively little attention has been paid towards the fabrication of in situ-formed LC sensing devices. Herein, we demonstrate a highly reproducible method to create uniform LC thin film on treated substrates, as needed, for LC sensing. We use shear forces generated by the laminar flow of aqueous liquid within a microfluidic channel to create LC thin films stabilized within microfabricated structures. The orientational response of the LC thin films to targeted analytes in aqueous phases was transduced and amplified by the optical birefringence of the LC thin films. The biochemical sensing capability of our sensing devices was demonstrated through experiments employing two chemical systems: dodecyl trimethylammonium bromide (DTAB) dissolved in an aqueous solution, and the hydrolysis of phospholipids by the enzyme phospholipase A(2) (PLA(2)).
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Affiliation(s)
- Ye Liu
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Daming Cheng
- Material Science Program, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
| | - I-Hsin Lin
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Nicholas L. Abbott
- Material Science Program, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
| | - Hongrui Jiang
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
- Material Science Program, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, WI 53706, USA
- Fax: 1-608-262-1267; Tel: 1-608-265-9418;
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31
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Sohn EH, Kang H, Kim DG, Song K, Lee JC. Collapse of Homeotropic Liquid-Crystal Alignment by Increased Molecular Packing on Comb-Like Polymer Surfaces. Chemphyschem 2012; 13:2061-7. [DOI: 10.1002/cphc.201200051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/19/2012] [Indexed: 11/11/2022]
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