1
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Huang C, Zhang X, Lyu X. Encounter between Gyroid and Lamellae in Janus Colloidal Particles Self-Assembled by a Rod-Coil Block Copolymer. Macromol Rapid Commun 2024; 45:e2300696. [PMID: 38160322 DOI: 10.1002/marc.202300696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Controlling the internal structure of block copolymer (BCP) particles has a significant influence on its functionalities. Here, a structure-controlling method is proposed to regulate the internal structure of BCP Janus colloidal particles using different surfactants. Different microphase separation processes take place in two connected halves of the Janus particles. An order-order transition between gyroid and lamellar phases is observed in polymeric colloids. The epitaxial growth during the structural transformation from gyroid to lamellar phase undergoes a two-layered rearrangement to accommodate the interdomain spacing mismatch between these two phases. This self-assembly behavior can be ascribed to the preferential wetting of BCP chains at the interface, which can change the chain conformation of different blocks. The Janus colloidal particles can further experience a reversible phase transition by restructuring the polymer particles under solvent vapor. It is anticipated that the new phase behavior found in Janus particles can not only enrich the self-assembly study of BCPs but also provide opportunities for various applications based on Janus particles with ordered structures.
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Affiliation(s)
- Chunzhi Huang
- Key Laboratory of Advanced Materials Technologies, International (HongKong Macao and Taiwan) Joint Laboratory on Advanced Materials Technologies, College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Xinyue Zhang
- Key Laboratory of Advanced Materials Technologies, International (HongKong Macao and Taiwan) Joint Laboratory on Advanced Materials Technologies, College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Xiaolin Lyu
- Key Laboratory of Advanced Materials Technologies, International (HongKong Macao and Taiwan) Joint Laboratory on Advanced Materials Technologies, College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian, 350108, China
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2
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Xu GX, Yuan XF, Liu QS, Wang H. Concentration Scaling on Linear Viscoelastic Properties of Cellular Suspensions and Effects of Equilibrium Phase Behavior. Int J Mol Sci 2023; 24. [PMID: 36835519 DOI: 10.3390/ijms24044107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
Concentration scaling on linear viscoelastic properties of cellular suspensions has been studied by rheometric characterisation of Phormidium suspensions and human blood in a wide range of volume fraction under small amplitude oscillatory shear experiments. The rheometric characterisation results are analysed by the time-concentration superposition (TCS) principle and show a power law scaling of characteristic relaxation time, plateau modulus and the zero-shear viscosity over the concentration ranges studied. The results show that the concentration effect of Phormidium suspensions on their elasticity is much stronger than that of human blood due to its strong cellular interactions and a high aspect ratio. For human blood, no obvious phase transition could be observed over the range of hematocrits studied here and with respect to a high-frequency dynamic regime, only one concentration scaling exponent could be identified. For Phormidium suspensions with respect to a low-frequency dynamic regime, three concentration scaling exponents in the volume fraction Region I (0.36≤ϕ/ϕref≤0.46), Region II (0.59≤ϕ/ϕref≤2.89) and Region III (3.11≤ϕ/ϕref≤3.44) are identified. The image observation shows that the network formation of Phormidium suspensions occurs as the volume fraction is increased from Region I to Region II; the sol-gel transition takes place from Region II to Region III. In combination with analysis of other nanoscale suspensions and liquid crystalline polymer solutions reported in the literature, it is revealed that such a power law concentration scaling exponent depends on colloidal or molecular interactions mediated with solvent and is sensitive to the equilibrium phase behaviour of complex fluids. The TCS principle is an unambiguous tool to give a quantitative estimation.
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3
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Lv XC, Lu L, Zuo XX, Achalkumar AS, Zhao AJ, Bermeshev MV, Wang FM, Ngeontae W, Ren XK. Supramolecular Structure and Photo-Thermo-Electric Property of Hydrogen-Bonded Liquid Crystalline Polymer Containing Poly(4-vinylpridine) and Cyanostilbene Side Chains. Chemistry 2023; 29:e202204060. [PMID: 36622137 DOI: 10.1002/chem.202204060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/10/2023]
Abstract
A series of side-chain liquid crystalline polymers P4VP(CN-DBE)x , where x is the molar ratio of cyanostilbene (CN-DBE) to poly(4-vinylpyridine) (P4VP) repeating unit, was synthesized based on the intermolecular hydrogen bonding between P4VP and CN-DBE. Their luminescent property, liquid crystalline structure and photo-thermo-electric property were elucidated using photoluminescence spectra, X-ray diffraction, thermal imaging and thermoelectric experiments. With the increase of x, the supramolecular system can be changed from lamellar structure to hexagonal columnar structure. Moreover, the P4VP(CN-DBE)x polymer with columnar structure exhibits more efficient photothermal effect. The temperature of P4VP(CN-DBE)0.6 can rise to 130 °C within 10 s under the irradiation of ultraviolet lamp. In addition, the supramolecular system possesses unique photo-thermo-electric conversion ability, and 25 mA current can be detected in the circuit coupled with the thermoelectric module. This work broadens the potential applications of hydrogen-bonded polymer, and provides a simple and facile strategy to prepare liquid crystalline polymers with photo-thermo-electric property.
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Affiliation(s)
- Xu-Chen Lv
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, 300350, Tianjin, P. R. China
| | - Lin Lu
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, 300350, Tianjin, P. R. China
| | - Xin-Xiao Zuo
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, 300350, Tianjin, P. R. China
| | | | - Ai-Juan Zhao
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, 300350, Tianjin, P. R. China
| | - Maxim V Bermeshev
- A. V. Topchiev Institute of Petrochemical Synthesis of, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Fu-Min Wang
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, 300350, Tianjin, P. R. China
| | - Wittaya Ngeontae
- Department of Chemistry, Faculty of Science, Khon Kaen University, 40002, Khon Kaen, Thailand
| | - Xiang-Kui Ren
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, 300350, Tianjin, P. R. China
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4
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Inoue Y, Takada K, Kawamura A, Miyata T. Amphiphilic Liquid Crystalline Polymer Micelles That Exhibit a Phase Transition at Body Temperature. ACS Appl Mater Interfaces 2022; 14:31513-31524. [PMID: 35767380 DOI: 10.1021/acsami.2c00592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Liquid crystalline polymers (LCPs), which exhibit unique structures and properties intermediate between those of liquids and solids, are widely utilized as functional and advanced materials for fabricating optical devices and high-performance fibers. This utility stems from their ability to abruptly change their organized structures and mobilities at their liquid crystalline-isotropic phase transition temperatures, similar to the properties of biological membranes. Despite these numerous potential applications of LCPs, no study on their use in medical applications such as drug delivery has been reported. In the present study, we synthesized amphiphilic side-chain LCPs (LCP-g-OEGs, where OEG is oligo(ethylene glycol)) for medical applications, where the LCP-g-OEGs undergo a nematic-isotropic phase transition at body temperature. The LCP-g-OEGs formed micelles with a diameter of approximately 130 nm in aqueous media. The micelles were stable and did not dissociate in aqueous media even when the temperature exceeded the nematic-isotropic phase transition temperature (TNI). Although the release of a dye as a model drug from micelles was suppressed at temperatures lower than TNI, their dye release was drastically enhanced at temperatures higher than TNI. The LCP-g-OEG micelles regulated dye release reversibly in accordance with stepwise changes in temperature, without undergoing dissociation, differing from the behavior of standard temperature-responsive micelles. The temperature-responsive dye release behavior is induced by dramatic changes in their well-organized and dynamic structures as a result of the nematic-isotropic phase transition. These results demonstrate that the LCP-g-OEG micelles have a lot of medical applications as reversibly stimuli-responsive drug carriers.
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Affiliation(s)
- Yasuaki Inoue
- Department of Chemistry and Materials Engineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan
| | - Kazuhito Takada
- Department of Chemistry and Materials Engineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan
| | - Akifumi Kawamura
- Department of Chemistry and Materials Engineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan
- Organization for Research and Development of Innovative Science and Technology, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan
| | - Takashi Miyata
- Department of Chemistry and Materials Engineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan
- Organization for Research and Development of Innovative Science and Technology, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan
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5
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Wang Z, Lan R, Bao J, Shen C, Huang R, Song C, Zhang L, Yang H. Reprogrammable Humidity-Driven Liquid Crystalline Polymer Actuator Enabled by Dynamic Ionic Bonds. ACS Appl Mater Interfaces 2022; 14:17869-17877. [PMID: 35384664 DOI: 10.1021/acsami.2c04662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Liquid crystalline polymer (LCP) is a promising candidate in the design and fabrication of intelligent soft materials due to the combination of programmable anisotropy and elasticity. Here, a novel strategy to fabricate reprogrammable humidity-responsive LCP materials enabled by dynamic ionic cross-links were put forward. The prepared LCP film deforms reversibly with the change of relative humidity (RH). However, the humidity responsivity loses after soaking the film into CaCl2 solution because of the lock of hygroscopic groups by the formed ionic bonds. By selectively cross-linking specific regions of the LCP film, distinctive humidity-driven motions of the film could be realized. More interestingly, by the EDTA-2K solution treatment, ionic cross-links can be interrupted, leading the LCP film responsive to humidity again. Thanks to feasibly removable ionic cross-links, the humidity-directed soft actuator was totally reprogrammable. The behavior of the novel actuator could be manipulated by either the mesogens alignment or the spatially ionic treatment, providing a feasible but robust strategy to fabricate complex humidity-driven soft robots.
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Affiliation(s)
- Zizheng Wang
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Polymers Chemistry and Physics of Ministry of Education, Beijing 100871, China
| | - Ruochen Lan
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Polymers Chemistry and Physics of Ministry of Education, Beijing 100871, China
| | - Jinying Bao
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Polymers Chemistry and Physics of Ministry of Education, Beijing 100871, China
| | - Chen Shen
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Polymers Chemistry and Physics of Ministry of Education, Beijing 100871, China
| | - Rui Huang
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100871, China
| | - Chenjie Song
- Department of Ophthalmology, Capital Medical University, Beijing Anzhen Hospital, Beijing 100029, China
| | - Lanying Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Polymers Chemistry and Physics of Ministry of Education, Beijing 100871, China
| | - Huai Yang
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- Key Laboratory of Polymers Chemistry and Physics of Ministry of Education, Beijing 100871, China
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6
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Hu W, Sun C, Ren Y, Qin S, Shao Y, Zhang L, Wu Y, Wang Q, Yang H, Yang D. Programmable Chromism and Photoluminescence of Spiropyran-Based Liquid Crystalline Polymer with Tunable Glass Transition Temperature. Angew Chem Int Ed Engl 2021; 60:19406-19412. [PMID: 34164902 DOI: 10.1002/anie.202107048] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 11/05/2022]
Abstract
Spiropyran-based materials (SPBMs) can give responses to the stimulations induced by the light, heat, force, or pH, which have been used as triggers for many smart materials. Here, a cross-linkable SPBM containing mesogenic-units is synthesized, which is pale-colored, non-photoluminescent and non-mesogenic at a spiro form, but dark-colored, photoluminescent, and mesogenic at a merocyanine form. Moreover, the dynamic interconversion behavior of the form in the different chemical environments are distinct. Liquid crystalline polymers (LCPs) containing the SPBMs cross-linked via visible light, own a photoswitchable glass transition temperature (Tg ) and retain the switchable property; however, the SPBMs cross-linked via UV light will be locked at the MC state, because the molecular movement was frozen at the room temperature lower than the given Tg of the LCP. Thus, programmable chromism and photoluminescence based on the tunable Tg can be endowed to the functional materials prepared from the SPBMs.
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Affiliation(s)
- Wei Hu
- Beijing Advanced Innovation Center for Materials Genome Engineering & Department of Materials Science and Engineering College of Engineering, Peking University, Beijing, 100871, P. R. China
| | - Chang Sun
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Yunxiao Ren
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Shengyu Qin
- Beijing Advanced Innovation Center for Materials Genome Engineering & Department of Materials Science and Engineering College of Engineering, Peking University, Beijing, 100871, P. R. China
| | - Yu Shao
- Beijing Advanced Innovation Center for Materials Genome Engineering & Department of Materials Science and Engineering College of Engineering, Peking University, Beijing, 100871, P. R. China
| | - Lanying Zhang
- Beijing Advanced Innovation Center for Materials Genome Engineering & Department of Materials Science and Engineering College of Engineering, Peking University, Beijing, 100871, P. R. China
| | - Yu Wu
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, P. R. China
| | - Qian Wang
- Beijing Advanced Innovation Center for Materials Genome Engineering & Department of Materials Science and Engineering College of Engineering, Peking University, Beijing, 100871, P. R. China
| | - Huai Yang
- Beijing Advanced Innovation Center for Materials Genome Engineering & Department of Materials Science and Engineering College of Engineering, Peking University, Beijing, 100871, P. R. China
| | - Dengke Yang
- Chemical Physics Interdisciplinary Program in Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA
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7
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Wang T, Li X, Dong Z, Huang S, Yu H. Vertical Orientation of Nanocylinders in Liquid-Crystalline Block Copolymers Directed by Light. ACS Appl Mater Interfaces 2017; 9:24864-24872. [PMID: 28670902 DOI: 10.1021/acsami.7b06086] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The microphase-separated nanostructures of block copolymers are ideal nanotemplates for advanced fabrication, but they are greatly limited by the rapid and precise manipulation especially at room temperature. Here we report one method of light-directed regulation of nanostructures in thin films of liquid-crystalline diblock copolymers containing azobenzene units as photoresponsive mesogens. The in-plane orientated nanocylinders in thin film can be light-directed into out-of-plane on a time scale of seconds at room temperature. This fast regulation is beneficial from the fast process of photoinduced phase transition of the mesogenic block from liquid crystal to disordered isotropic phase. Several influence factors like the molecular weight of polymer, film thickness, light intensity, and relative humidity were studied in the light-directed processes. In addition, the photoregulated nanostructures demonstrate their capability of being photopatterned and further used as nanotemplates for fabrication of nanoparticles. The light-directed method shows noncontact, precise, and reversible features, enabling it to find further applications in fast control of nanostructures for nanofabrication and nanoengineering.
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Affiliation(s)
- Tianjie Wang
- Department of Materials Science and Engineering, College of Engineering and Engineering and Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, P. R. China
| | - Xiao Li
- Department of Materials Science and Engineering, College of Engineering and Engineering and Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, P. R. China
| | - Zhijiao Dong
- Department of Materials Science and Engineering, College of Engineering and Engineering and Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, P. R. China
| | - Shuai Huang
- Department of Materials Science and Engineering, College of Engineering and Engineering and Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, P. R. China
| | - Haifeng Yu
- Department of Materials Science and Engineering, College of Engineering and Engineering and Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, P. R. China
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8
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Ryabchun A, Raguzin I, Stumpe J, Shibaev V, Bobrovsky A. Cholesteric Polymer Scaffolds Filled with Azobenzene-Containing Nematic Mixture with Phototunable Optical Properties. ACS Appl Mater Interfaces 2016; 8:27227-27235. [PMID: 27633069 DOI: 10.1021/acsami.6b09642] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The past two decades witnessed tremendous progress in the field of creation of different types of responsive materials. Cholesteric polymer networks present a very promising class of smart materials due to the combination of the unique optical properties of cholesteric mesophase and high mechanical properties of polymer networks. In the present work we demonstrate the possibility of fast and reversible photocontrol of the optical properties of cholesteric polymer networks. Several cholesteric photopolymerizable mixtures are prepared, and porous cholesteric network films with different helix pitches are produced by polymerization of these mixtures. An effective and simple method of the introduction of photochromic azobenzene-containing nematic mixture capable of isothermal photoinducing the nematic-isotropic phase transition into the porous polymer matrix is developed. It is found that cross-linking density and degree of polymer network filling with a photochromic nematic mixture strongly influence the photo-optical behavior of the obtained composite films. In particular, the densely cross-linked films are characterized by a decrease in selective light reflection bandwidth, whereas weakly cross-linked systems display two processes: the shift of selective light reflection peak and decrease of its width. It is noteworthy that the obtained cholesteric materials are shown to be very promising for the variety applications in optoelectronics and photonics.
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Affiliation(s)
- Alexander Ryabchun
- Fraunhofer Institute for Applied Polymer Research , Geiselbergstrasse 69, 14476 Potsdam-Golm, Germany
- Chemistry Department, Moscow State University , Lenin Hills 1, 119991 Moscow, Russia
| | - Ivan Raguzin
- Leibniz Institute of Polymer Research , Hohe Strasse 6, 01069 Dresden, Germany
| | - Joachim Stumpe
- University of Potsdam , Am Mühlenberg 11, 14476 Potsdam, Germany
| | - Valery Shibaev
- Chemistry Department, Moscow State University , Lenin Hills 1, 119991 Moscow, Russia
| | - Alexey Bobrovsky
- Chemistry Department, Moscow State University , Lenin Hills 1, 119991 Moscow, Russia
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9
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Wierzba P. Interferometric Sensor of Wavelength Detuning Using a Liquid Crystalline Polymer Waveplate. Sensors (Basel) 2016; 16:E633. [PMID: 27171082 DOI: 10.3390/s16050633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/20/2016] [Accepted: 04/25/2016] [Indexed: 11/16/2022]
Abstract
Operation of a polarization interferometer for measurement of the wavelength changes of a tunable semiconductor laser was investigated. A λ/8 waveplate made from liquid crystalline polymer is placed in one of interferometers’ arms in order to generate two output signals in quadrature. Wavelength was measured with resolution of 2 pm in the wavelength range 628–635 nm. Drift of the interferometer, measured in the period of 500 s, was 8 nm, which corresponded to the change in the wavelength of 1.3 pm. If needed, wavelength-dependent Heydemann correction can be used to expand the range of operation of such interferometer.
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10
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Zhao H, Wie JJ, Copic D, Oliver CR, Orbaek White A, Kim S, Hart AJ. High-Fidelity Replica Molding of Glassy Liquid Crystalline Polymer Microstructures. ACS Appl Mater Interfaces 2016; 8:8110-7. [PMID: 26943057 DOI: 10.1021/acsami.6b00785] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Liquid crystalline polymers have recently been engineered to exhibit complex macroscopic shape adaptivity, including optically- and thermally driven bending, self-sustaining oscillation, torsional motion, and three-dimensional folding. Miniaturization of these novel materials is of great interest for both fundamental study of processing conditions and for the development of shape-changing microdevices. Here, we present a scalable method for high-fidelity replica molding of glassy liquid crystalline polymer networks (LCNs), by vacuum-assisted replica molding, along with magnetic field-induced control of the molecular alignment. We find that an oxygen-free environment is essential to establish high-fidelity molding with low surface roughness. Identical arrays of homeotropic and polydomain LCN microstructures are fabricated to assess the influence of molecular alignment on the elastic modulus (E = 1.48 GPa compared to E = 0.54 GPa), and side-view imaging is used to quantify the reversible thermal actuation of individual LCN micropillars by high-resolution tracking of edge motion. The methods and results from this study will be synergistic with future advances in liquid crystalline polymer chemistry, and could enable the scalable manufacturing of stimuli-responsive surfaces for applications including microfluidics, tunable optics, and surfaces with switchable wetting and adhesion.
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Affiliation(s)
- Hangbo Zhao
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jeong Jae Wie
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department of Polymer Science and Engineering, Inha University , 100 Inha-ro, Nam-gu, Incheon 402-751, Republic of Korea
| | - Davor Copic
- Department of Mechanical Engineering, University of Michigan , 2350 Hayward Street, Ann Arbor, Michigan 48109, United States
| | - C Ryan Oliver
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alvin Orbaek White
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sanha Kim
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - A John Hart
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department of Mechanical Engineering, University of Michigan , 2350 Hayward Street, Ann Arbor, Michigan 48109, United States
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11
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Ryabchun A, Bobrovsky A, Gritsai Y, Sakhno O, Shibaev V, Stumpe J. Stable selective gratings in LC polymer by photoinduced helix pitch modulation. ACS Appl Mater Interfaces 2015; 7:2554-2560. [PMID: 25541812 DOI: 10.1021/am507499p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A cholesteric mixture based on the nematic liquid crystalline side-chain polymer doped with a chiral-photochromic compound was prepared and used as an active medium for creation of stable polarization selective gratings by phototunable modulation of the helix pitch. Such modulation was fabricated in the polymer mixture by a nonpolarized UV-irradiation with spatially modulated intensity that causes E-Z isomerization of a chiral-photochromic dopant, decreasing its helical twisting power. It was shown that the gratings recorded by UV-exposure through a mask are strongly selective to the handedness of circular polarized light. The studied polymer film forms a right-handed helical structure and, correspondingly, the diffraction of only the right-circularly polarized light was found in the transmittance mode. The maximum diffraction efficiencies were found for the wavelength values between the maxima of selective light reflection. The films obtained open very interesting possibilities for further development of materials with stable gratings operating in the entire visible spectral range. Both the position and the width of the spectral range of an efficient diffraction can be easily controlled by the UV exposure and concentration of the dopant. The materials obtained and methods developed can be used for creation of specific diffraction elements for optics and photonics.
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Affiliation(s)
- Alexander Ryabchun
- Fraunhofer Institute for Applied Polymer Research , Geiselbergstr. 69, Potsdam/Golm, 14476 Germany
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12
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Forest MG, Phuworawong P, Wang Q, Zhou R. Rheological signatures in limit cycle behaviour of dilute, active, polar liquid crystalline polymers in steady shear. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2013.0362. [PMID: 25332387 PMCID: PMC4223670 DOI: 10.1098/rsta.2013.0362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We consider the dilute regime of active suspensions of liquid crystalline polymers (LCPs), addressing issues motivated by our kinetic model and simulations in Forest et al. (Forest et al. 2013 Soft Matter 9, 5207-5222 (doi:10.1039/c3sm27736d)). In particular, we report unsteady two-dimensional heterogeneous flow-orientation attractors for pusher nanorod swimmers at dilute concentrations where passive LCP equilibria are isotropic. These numerical limit cycles are analogous to longwave (homogeneous) tumbling and kayaking limit cycles and two-dimensional heterogeneous unsteady attractors of passive LCPs in weak imposed shear, yet these states arise exclusively at semi-dilute concentrations where stable equilibria are nematic. The results in Forest et al. mentioned above compel two studies in the dilute regime that complement recent work of Saintillan & Shelley (Saintillan & Shelley 2013 C. R. Physique 14, 497-517 (doi:10.1016/j.crhy.2013.04.001)): linearized stability analysis of the isotropic state for nanorod pushers and pullers; and an analytical-numerical study of weakly and strongly sheared active polar nanorod suspensions to capture how particle-scale activation affects shear rheology. We find that weakly sheared dilute puller versus pusher suspensions exhibit steady versus unsteady responses, shear thickening versus thinning and positive versus negative first normal stress differences. These results further establish how sheared dilute nanorod pusher suspensions exhibit many of the characteristic features of sheared semi-dilute passive nanorod suspensions.
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Affiliation(s)
- M Gregory Forest
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Panon Phuworawong
- Department of Mathematics and Statistics, Old Dominion University, Norfolk, VA 23529, USA
| | - Qi Wang
- Department of Mathematics, University of South Carolina, Columbia, SC 29208, USA
| | - Ruhai Zhou
- Department of Mathematics and Statistics, Old Dominion University, Norfolk, VA 23529, USA
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McConney ME, Martinez A, Tondiglia VP, Lee KM, Langley D, Smalyukh II, White TJ. Topography from topology: photoinduced surface features generated in liquid crystal polymer networks. Adv Mater 2013; 25:5880-5. [PMID: 23873775 DOI: 10.1002/adma.201301891] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 05/29/2013] [Indexed: 05/12/2023]
Abstract
Films subsumed with topological defects are transformed into complex, topographical surface features with light irradiation of azobenzene-functionalized liquid crystal polymer networks (azo-LCNs). Using a specially designed optical setup and photoalignment materials, azo-LCN films containing either singular or multiple defects with strengths ranging from |½| to as much as |10| are examined. The local order of an azo-LCN material for a given defect strength dictates a complex, mechanical response observed as topographical surface features.
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Affiliation(s)
- Michael E McConney
- Air Force Research Laboratory, Materials and Manufacturing Directorate, 3005 Hobson Way, WPAFB, OH, 45434, USA
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