1
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Kocaman C, Batir O, Bukusoglu E. Optically responsive dry cholesteric liquid crystal marbles. J Colloid Interface Sci 2024; 671:374-384. [PMID: 38815373 DOI: 10.1016/j.jcis.2024.05.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/22/2024] [Accepted: 05/25/2024] [Indexed: 06/01/2024]
Abstract
Dry liquid crystal marbles are structures that consist of cholesteric liquid crystal (CLC) droplets prepared by the mixture of chiral-doped thermotropic LCs encapsulated by cellulose nanocrystals (CNCs) that have been dried under ambient conditions. The characterizations revealed that CLC droplets were successfully encapsulated by self-standing CNC shells and responsive to the external gaseous stimulus. The dry LC marbles offer several advantages over previously reported LC-based gas sensors, such as fast response against minor external stimuli, and ease of handling, which make them particularly attractive for practical applications in sensing. We demonstrate the use of these marbles for detecting toluene vapor, a common industrial solvent and pollutant, which we also use to understand the response characteristics. The dry CLC marbles exhibit a significant response to toluene vapor with a detection limit below 500 ppm, attributed to the change of pitch size of the helical structure of CLC droplets induced by the toluene vapor. The CNC-capsulated CLC droplets were stable in emulsion for up to two weeks, and their dried form exhibited a sensitive response upon toluene exposure. The real-time experiments revealed that the LC marbles can be used multiple times without a significant loss of sensitivity, where 90 % of the maximum response was observed at 13.3 ± 4.7 s. These dry LC marbles can also be utilized in other areas, including drug delivery, optical devices, and biosensors.
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Affiliation(s)
- Ceren Kocaman
- Department of Chemical Engineering, Middle East Technical University, Dumlupınar Bulvarı No.1 Çankaya, Ankara, 06800, Turkiye; Laboratory of Advanced Separations (LAS), École Polytechnique Fédérale de Lausanne (EPFL), Sion 1950, Switzerland
| | - Ozge Batir
- Department of Chemical Engineering, Middle East Technical University, Dumlupınar Bulvarı No.1 Çankaya, Ankara, 06800, Turkiye
| | - Emre Bukusoglu
- Department of Chemical Engineering, Middle East Technical University, Dumlupınar Bulvarı No.1 Çankaya, Ankara, 06800, Turkiye.
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2
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Wang J, Wen Y, Pan D, Lin S, Chinnappan A, He Q, Liu C, Huang Z, Cai S, Ramakrishna S, Shin S. High Thermal Conductive Liquid Crystal Elastomer Nanofibers. NANO LETTERS 2024; 24:9990-9997. [PMID: 39101516 DOI: 10.1021/acs.nanolett.4c02752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Liquid crystal elastomers (LCEs), consisting of polymer networks and liquid crystal mesogens, show a reversible phase change under thermal stimuli. However, the kinetic performance is limited by the inherently low thermal conductivity of the polymers. Transforming amorphous bulk into a fiber enhances thermal conductivity through the alignment of polymer chains. Challenges are present due to their rigid networks, while cross-links are crucial for deformation. Here, we employ hydrodynamic alignment to orient the LCE domains assisted by controlled in situ cross-linking and to remarkably reduce the diameter to submicrons. We report that the intrinsic thermal conductivity of LCE fibers at room temperature reaches 1.44 ± 0.32 W/m-K with the sub-100 nm diameter close to the upper limit determined in the quasi-1D regime. Combining the outstanding thermal conductivity and thin diameters, we anticipate these fibers to exhibit a rapid response and high force output in thermomechanical systems. The fabrication method is expected to apply to other cross-linked polymers.
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Affiliation(s)
- Jingxuan Wang
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Yue Wen
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Duo Pan
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education; National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China
| | - Shulang Lin
- Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Amutha Chinnappan
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Qiguang He
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin 999077, Hong Kong, China
| | - Chuntai Liu
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education; National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China
| | - Zhiwei Huang
- Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, United States of America
| | - Seeram Ramakrishna
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Sunmi Shin
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117575, Singapore
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3
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Rešetič A. Shape programming of liquid crystal elastomers. Commun Chem 2024; 7:56. [PMID: 38485773 PMCID: PMC10940691 DOI: 10.1038/s42004-024-01141-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/07/2024] [Indexed: 03/18/2024] Open
Abstract
Liquid crystal elastomers (LCEs) are shape-morphing materials that demonstrate reversible actuation when exposed to external stimuli, such as light or heat. The actuation's complexity depends heavily on the instilled liquid crystal alignment, programmed into the material using various shape-programming processes. As an unavoidable part of LCE synthesis, these also introduce geometrical and output restrictions that dictate the final applicability. Considering LCE's future implementation in real-life applications, it is reasonable to explore these limiting factors. This review offers a brief overview of current shape-programming methods in relation to the challenges of employing LCEs as soft, shape-memory components in future devices.
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Affiliation(s)
- Andraž Rešetič
- Jožef Stefan Institute, Solid State Physics Department, Jamova cesta 39, 1000, Ljubljana, Slovenia.
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4
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Wang Y, Tang X, XinWei, Gao S, Jiang L, Yi Y. Study of CO 2 adsorption on carbon aerogel fibers prepared by electrospinning. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 349:119432. [PMID: 37948959 DOI: 10.1016/j.jenvman.2023.119432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/25/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
The exacerbation of climate change has made the development of alternative and sustainable technologies to achieve carbon neutrality an urgent matter. The intricate preparation and arduous recovery of conventionally prepared CO2 solid adsorbents make their large-scale application a significant challenge, which significantly limits the application of the adsorbent. To address this problem, we have innovatively adopted a novel strategy of electrospinning and one-step carbonization to fabricate microporous carbon aerogel fibers (CAFs) as solid adsorbents for CO2. This method offers the advantages of a simple process, cost-effectiveness, and stable performance. The designed CAFs possess a high specific surface area (1188.628 m2/g), an appropriate distribution of pore size (0.54-0.64 nm), and about 15 at% oxygen-containing functional groups without activation or doping. At 0 °C, the CAFs-800 (800 is the carbonization temperature) exhibit a maximum capture capacity of 4.25 mmol/g, and after 5 times cycles, the adsorption capacity remains above 97%; at 25 °C, the maximum capture capacity reaches 3.57 mmol/g of CAFs-800, surpassing similar materials by more than 20%, demonstrating excellent adsorption capacity and stability towards CO2. These results indicate that the CAFs hold great promise for CO2 capture and storage with exceptional advantages.
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Affiliation(s)
- Yiyang Wang
- State Key Laboratory for Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, PR China
| | - Xiaodi Tang
- State Key Laboratory for Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, PR China
| | - XinWei
- State Key Laboratory for Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, PR China
| | - Shijie Gao
- State Key Laboratory for Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, PR China
| | - Lili Jiang
- State Key Laboratory for Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, PR China
| | - Yong Yi
- State Key Laboratory for Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, PR China.
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5
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Fallah-Darrehchi M, Zahedi P. Improvement of Intracellular Interactions through Liquid Crystalline Elastomer Scaffolds by the Alteration of Topology. ACS OMEGA 2023; 8:46878-46891. [PMID: 38107894 PMCID: PMC10720303 DOI: 10.1021/acsomega.3c06528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/23/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Preparation of inherently bioactive scaffolds has become a challenging issue owing to their complicated synthesis and nonrobust modified cell-actuating property. Liquid crystalline elastomers (LCEs), due to their combined specialties of liquid crystals and elastomers as well as their ability to respond to various kinds of stimuli, have reversibly led to the design of a new class of stimuli-responsive tissue-engineered scaffolds. In this line, in the first stage of this research work, synthesis and evaluation of acrylate-based LCE films (LCEfilm) encompassing mesogenic monomers are carried out. In the second step, the design of an affordable electrospinning technique for preparing LCE nanofibers (LCEfiber) as a problematic topic, thanks to the low molecular weight of the mesogenic chains of LCEs, is investigated. For this purpose, two approaches are considered, including (1) photo-cross-linking of electrospun LCEfiber and (2) blending LCE with poly(ε-caprolactone) (PCL) to produce morphologically stable nanofibers (PCL-LCEfiber). In the following, thermal, mechanical, and morphological evaluations show the optimized crosslinker (mol)/aliphatic spacer (mol) molar ratio of 50:50 for LCEfilm samples. On the other hand, for LCEfiber samples, the appropriate amounts of excessive mesogenic monomer and PCL/LCE (v/v) to fabricate the uniform nanofibers are determined to be 20% and 1:2, respectively. Eventually, PC12 cell compatibility and the impact of the liquid crystalline phase on the PC12 cell dynamic behavior of the samples are examined. The obtained results reveal that PC12 cells cultured on electrospun PCL-LCEfiber nanofibers with an average diameter of ∼659 nm per sample are alive and the scaffold has susceptibility for cell proliferation and actuation because of the rapid increase in cell density and number of singularity points formed in time-lapse cell imaging. Moreover, the PCL-LCEfiber nanofibrous scaffold exhibits a high performance for cell differentiation according to detailed biological evaluations such as gene expression level measurements. The time-lapse evaluation of PC12 cell flow fields confirms the significant influence of the reprogrammable liquid crystalline phase in the PCL-LCEfiber nanofibrous scaffold on topographical cue induction compared to the biodegradable PCL nanofibers.
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Affiliation(s)
- Mahshid Fallah-Darrehchi
- Nano-Biopolymers Research
Laboratory, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 1417613131, Iran
| | - Payam Zahedi
- Nano-Biopolymers Research
Laboratory, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 1417613131, Iran
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6
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Geng Y, Lagerwall JP. Multiresponsive Cylindrically Symmetric Cholesteric Liquid Crystal Elastomer Fibers Templated by Tubular Confinement. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301414. [PMID: 37186075 PMCID: PMC10323659 DOI: 10.1002/advs.202301414] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/02/2023] [Indexed: 05/17/2023]
Abstract
Cylindrically symmetric cholesteric liquid crystal elastomer (CLCE) fibers templated by tubular confinement are reported, displaying mechanochromic, thermochromic, and thermomechanical responses. The synthesis inside a sacrificial tube secures radial orientation of the cholesteric helix, and the ground state retroreflection wavelength is easily tuned throughout the visible spectrum or into the near-infrared by varying the concentration of a chiral dopant. The fibers display continuous, repeatable, and quantitatively predictable mechanochromic response, reaching a blue shift of more than -220 nm for 180% elongation. The cylindrical symmetry renders the response identical in all directions perpendicular to the fiber axis, making them exceptionally useful for monitoring complex strains, as demonstrated in revealing local strain during tying of different knots. The CLCE reflection color can be revealed with high contrast against any background by taking advantage of the circularly polarized reflection. Upon heating, the fibers respond-fully reversibly-with red shift and radial expansion/axial contraction. However, there is no transition to an isotropic state, confirming a largely forgotten theoretical prediction by de Gennes. These fibers and the easy way of making them may open new windows for large-scale application in advanced wearable technology and beyond.
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Affiliation(s)
- Yong Geng
- Experimental Soft Matter Physics groupDepartment of Physics and Materials ScienceUniversity of LuxembourgL‐1511LuxembourgLuxembourg
| | - Jan P.F. Lagerwall
- Experimental Soft Matter Physics groupDepartment of Physics and Materials ScienceUniversity of LuxembourgL‐1511LuxembourgLuxembourg
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7
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Hou W, Wang J, Lv JA. Bioinspired Liquid Crystalline Spinning Enables Scalable Fabrication of High-Performing Fibrous Artificial Muscles. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211800. [PMID: 36812485 DOI: 10.1002/adma.202211800] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Leveraging liquid crystal elastomers (LCEs) to realize scalable fabrication of high-performing fibrous artificial muscles is of particular interest because these active soft materials can provide large, reversible, programmable deformations upon environmental stimuli. High-performing fibrous LCEs require the used processing technology to enable shaping LCEs into micro-scale fine fibers as thin as possible while achieving macroscopic LC orientation, which however remains a daunting challenge. Here, a bioinspired spinning technology is reported that allows for continuous, high-speed production (fabrication speed up to 8400 m h-1 ) of thin and aligned LCE microfibers combined with rapid deformation (actuation strain rate up to 810% s-1 ), powerful actuation (actuation stress up to 5.3 MPa), high response frequency (50 Hz), and long cycle life (250 000 cycles without obvious fatigue). Inspired by liquid crystalline spinning of spiders that takes advantage of multiple drawdowns to thin and align their dragline silks, internal drawdown via tapered-wall-induced-shearing and external drawdown via mechanical stretching are employed to shape LCEs into long, thin, aligned microfibers with the desirable actuation performances, which few processing technologies can achieve. This bioinspired processing technology capable of scalable production of high-performing fibrous LCEs would benefit the development of smart fabrics, intelligent wearable devices, humanoid robotics, and other areas.
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Affiliation(s)
- Wenhao Hou
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Jiao Wang
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
| | - Jiu-An Lv
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang Province, 310024, China
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8
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Silva PES, Lin X, Vaara M, Mohan M, Vapaavuori J, Terentjev EM. Active Textile Fabrics from Weaving Liquid Crystalline Elastomer Filaments. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210689. [PMID: 36639143 DOI: 10.1002/adma.202210689] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Active fabrics, responding autonomously to environmental changes, are the "Holy Grail" of the development of smart textiles. Liquid crystal elastomers (LCEs) promise to be the base materials for large-stroke reversible actuation. The mechanical behavior of LCEs matches almost exactly the human muscle. Yet, it has not been possible to produce filaments from LCEs that will be suitable for standard textile production methods, such as weaving. Based on the recent development of LCE fibers, here, the crafting of active fabrics incorporating LCE yarn, woven on a standard loom, giving control over the weave density and structure, is presented. Two types of LCE yarns (soft and stiff) and their incorporation into several weaving patterns are tested, and the "champions" identified: the twill pattern with stiffer LCE yarn that shows the greatest blocking force of 1-2 N cm-1 , and the weft rib pattern with over 10% reversible actuation strain on repeated heating cycles. Reversible 3D shape changes of active fabric utilize the circular weaving patterns that lead to cone shapes upon heating. The seamless combination of active LCE yarns into the rich portfolio of existing passive yarns can be transformative in creating new stimuli-responsive actuating textiles.
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Affiliation(s)
- Pedro E S Silva
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, Kemistintie 1, Espoo, 02150, Finland
| | - Xueyan Lin
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Maija Vaara
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, Kemistintie 1, Espoo, 02150, Finland
| | - Mithila Mohan
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, Kemistintie 1, Espoo, 02150, Finland
| | - Jaana Vapaavuori
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, Kemistintie 1, Espoo, 02150, Finland
| | - Eugene M Terentjev
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
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9
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Zhang Z, Bolshakov A, Han J, Zhu J, Yang KL. Electrospun Core-Sheath Fibers with a Uniformly Aligned Polymer Network Liquid Crystal (PNLC). ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 36916499 DOI: 10.1021/acsami.2c23065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Electrospun polymer-liquid crystal (PLC) fibers have potential applications such as wearable sensors and adaptive textiles because of their rapid response and high flexibility. However, existing PLC fibers only have a narrow responsive range and poor resistance to heat and chemicals. Herein, a new type of PLC fiber is prepared by using a coaxial electrospinning process. The core solution is 4'-pentyl-4-biphenylcarbonitrile (5CB), and the sheath solution is a mixture containing 13 wt % PVP and 10 wt % reactive mesogen (RM). After UV exposure of the fibers, 5CB in the core and RM diffusing from the core are cross-linked into an LC polymer. The fibers have a highly uniform morphology with an average diameter of 3.2 ± 0.5 μm, and mesogens inside the fibers align unidirectionally with the long axis of the fibers. The fibers show a broad phase-transition temperature range between 13.5 and 155.5 °C and have a response time of less than 10 s. The temperature range can also be controlled by adjusting components in the electrospun fibers and UV exposure time. The core-sheath fibers prepared in such a manner exhibit excellent heat and chemical resistance with reversible optical responses. Moreover, when the fibers are exposed to volatile organic compounds (VOCs) such as toluene, the fibers show a rapid optical response to toluene vapor within 25 s. This study demonstrates that the fibers are potentially useful for preparing flexible temperature and chemical sensors.
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Affiliation(s)
- Zhibo Zhang
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore, Singapore
| | - Andrey Bolshakov
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China
| | - Jiecai Han
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China
| | - Jiaqi Zhu
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China
| | - Kun-Lin Yang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore, Singapore
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10
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Kim DS, Lee YJ, Wang Y, Park J, Winey KI, Yang S. Self-Folding Liquid Crystal Network Filaments Patterned with Vertically Aligned Mesogens. ACS APPLIED MATERIALS & INTERFACES 2022; 14:50171-50179. [PMID: 36282177 DOI: 10.1021/acsami.2c14947] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Fibrous soft actuators with high molecular anisotropy are of interest for shape morphing from 1D to 2D and 3D in response to external stimuli with high actuation efficiency. Nevertheless, few have fabricated fibrous actuators with controlled molecular orientations and stiffness. Here, we fabricate filaments from liquid crystal networks (LCNs) with segmental crosslinking density and gradient porosity from a mixture of di-acrylate mesogenic monomers and small-molecule nematic or smectic liquid crystals (LCs) filled in a capillary. During photopolymerization, phase separation between the small-molecule LCs and LCN occurs, making one side of the filament considerably denser than the other side. To direct its folding mode (bending or twisting), we control the alignment of LC molecules within the capillary, either along or perpendicular to the filament long axis. We show that the direction of UV exposure can determine the direction of phase separation, which in turn direct the deformation of the filament after removal of the small-molecule LCs. We find that the vertical alignment of LCs within the filament is essential to efficiently direct bending deformation. By photopatterning the filament with segmental crosslinking density, we can induce a reversible folding/unfolding into 2D and 3D geometries triggered by deswelling/swelling in an organic solvent. Moreover, by taking advantage of the large elastic modulus of LCNs and large contrast of the modulus before and after swelling, we show that the self-folded LCP filament could act as a strong gripper.
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Affiliation(s)
- Dae Seok Kim
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
- Department of Polymer Engineering, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, South Korea
| | - Young-Joo Lee
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Yuchen Wang
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Jinseok Park
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Karen I Winey
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Shu Yang
- Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
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11
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Honaker L, Chen C, Dautzenberg FM, Brugman S, Deshpande S. Designing Biological Microsensors with Chiral Nematic Liquid Crystal Droplets. ACS APPLIED MATERIALS & INTERFACES 2022; 14:37316-37329. [PMID: 35969154 PMCID: PMC9412956 DOI: 10.1021/acsami.2c06923] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 08/03/2022] [Indexed: 05/16/2023]
Abstract
Biosensing using liquid crystals has a tremendous potential by coupling the high degree of sensitivity of their alignment to their surroundings with clear optical feedback. Many existing set-ups use birefringence of nematic liquid crystals, which severely limits straightforward and frugal implementation into a sensing platform due to the sophisticated optical set-ups required. In this work, we instead utilize chiral nematic liquid crystal microdroplets, which show strongly reflected structural color, as sensing platforms for surface active agents. We systematically quantify the optical response of closely related biological amphiphiles and find unique optical signatures for each species. We detect signatures across a wide range of concentrations (from micromolar to millimolar), with fast response times (from seconds to minutes). The striking optical response is a function of the adsorption of surfactants in a nonhomogeneous manner and the topology of the chiral nematic liquid crystal orientation at the interface requiring a scattering, multidomain structure. We show that the surface interactions, in particular, the surface packing density, to be a function of both headgroup and tail and thus unique to each surfactant species. We show lab-on-a-chip capability of our method by drying droplets in high-density two-dimensional arrays and simply hydrating the chip to detect dissolved analytes. Finally, we show proof-of-principle in vivo biosensing in the healthy as well as inflamed intestinal tracts of live zebrafish larvae, demonstrating CLC droplets show a clear optical response specifically when exposed to the gut environment rich in amphiphiles. Our unique approach shows clear potential in developing on-site detection platforms and detecting biological amphiphiles in living organisms.
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Affiliation(s)
- Lawrence
W. Honaker
- Laboratory
of Physical Chemistry and Soft Matter, Wageningen
University & Research, Wageningen 6708 WE, The Netherlands
| | - Chang Chen
- Laboratory
of Physical Chemistry and Soft Matter, Wageningen
University & Research, Wageningen 6708 WE, The Netherlands
| | - Floris M.H. Dautzenberg
- Laboratory
of Physical Chemistry and Soft Matter, Wageningen
University & Research, Wageningen 6708 WE, The Netherlands
| | - Sylvia Brugman
- Host-Microbe
Interactomics, Wageningen University &
Research, Wageningen 6708 WD, The Netherlands
| | - Siddharth Deshpande
- Laboratory
of Physical Chemistry and Soft Matter, Wageningen
University & Research, Wageningen 6708 WE, The Netherlands
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12
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Wang ZZ, Zhang B, Weng X, Yu XD, Liu X, He TS. Application of electrospun polyimide-based porous nano-fibers separators in ionic liquid electrolyte for electrical double-layer capacitors. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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13
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Production and characterization of liquid crystal/polyacrylonitrile nano-fibers by electrospinning method. Colloid Polym Sci 2021. [DOI: 10.1007/s00396-021-04842-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Zhu C, Lu Y, Sun J, Yu Y. Dynamic Interfacial Regulation by Photodeformable Azobenzene-Containing Liquid Crystal Polymer Micro/Nanostructures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6611-6625. [PMID: 32449856 DOI: 10.1021/acs.langmuir.0c00582] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photoresponsive materials offer local, temporal, and remote control over their chemical or physical properties under external stimuli, giving new tools for interfacial regulation. Among all, photodeformable azobenzene-containing liquid crystal polymers (azo-LCPs) have received increasing attention because they can be processed into various micro/nanostructures and have the potential to reversibly tune the interfacial properties through chemical and/or morphological variation by light, providing effective dynamic interface regulation. In this feature article, we highlight the milestones in the dynamic regulation of different interfacial properties through micro/nanostructures made of photodeformable azobenzene-containing liquid crystal polymers (azo-LCPs). We describe the preparation of different azo-LCP micro/nanostructures from the aspects of materials and processing techniques and reveal the importance of mesogen orientation toward dynamic interfacial regulation. By introducing our recently developed linear azo-LCP (azo-LLCP) with good mechanical and photoresponsive performances, we discuss the challenge and opportunity with respect to the dynamic light regulation of two- and three-dimensional (2D/3D) micro/nanostructures to tune their related interfacial properties. We have also given our expectation toward exploring photodeformable micro/nanostructures for advanced applications such as in microfluidics, biosensors, and nanotherapeutics.
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Affiliation(s)
- Chongyu Zhu
- Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, 220 Handan Road, Shanghai, 200433, China
| | - Yao Lu
- Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, 220 Handan Road, Shanghai, 200433, China
| | - Jiahao Sun
- Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, 220 Handan Road, Shanghai, 200433, China
| | - Yanlei Yu
- Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, 220 Handan Road, Shanghai, 200433, China
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Reyes CG, Lagerwall JPF. Disruption of Electrospinning due to Water Condensation into the Taylor Cone. ACS APPLIED MATERIALS & INTERFACES 2020; 12:26566-26576. [PMID: 32420728 PMCID: PMC7302509 DOI: 10.1021/acsami.0c03338] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/18/2020] [Indexed: 05/28/2023]
Abstract
The well-known problems of electrospinning hygroscopic polymer fibers in humid air are usually attributed to water condensing onto the jet mid-flight: water enters the jet as an additional solvent, hindering solidification into well-defined fibers. Here, we show that fiber fusion and shape loss seen at the end of the process may actually stem from water already condensing into the Taylor cone from where the jet ejects, if the solvent is volatile and miscible with water, for example, ethanol. The addition of water can radically change the solvent character from good to poor, even if water on its own is an acceptable solvent. Moreover, and counterintuitively, the water condensation promotes solvent evaporation because of the release of heat through the phase transition as well as from the exothermic mixing process. The overall result is that the polymer solution develops a gel-like skin around the Taylor cone. The situation is significantly aggravated in the case of coaxial electrospinning to make functional composite fibers if the injected core fluid forms a complex phase diagram with miscibility gaps together with the polymer sheath solvent and the water condensing from the air. The resulting phase separation coagulates the polymer throughout the Taylor cone, as liquid droplets with different compositions nucleate and spread, setting up strong internal flows and concentration gradients. We demonstrate that these cases of uncontrolled polymer coagulation cause rapid Taylor cone deformation, multiple jet ejection, and the inability to spin coaxial fiber mats, illustrated by the example of coaxial electrospinning of an ethanolic polyvinylpyrrolidone solution with a thermotropic liquid crystal core, at varying humidities.
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McCracken JM, Donovan BR, White TJ. Materials as Machines. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906564. [PMID: 32133704 DOI: 10.1002/adma.201906564] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/19/2019] [Indexed: 05/23/2023]
Abstract
Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walking, crawling, swimming, and flying). Key functional considerations of responsive materials in machine implementations are response time, cyclability (frequency and ruggedness), sizing, payload capacity, amenability to mechanical programming, performance in extreme environments, and autonomy. This review summarizes the material transformation mechanisms, mechanical design, and robotic integration of responsive materials including shape memory alloys (SMAs), piezoelectrics, dielectric elastomer actuators (DEAs), ionic electroactive polymers (IEAPs), pneumatics and hydraulics systems, shape memory polymers (SMPs), hydrogels, and liquid crystalline elastomers (LCEs) and networks (LCNs). Structural and geometrical fabrication of these materials as wires, coils, films, tubes, cones, unimorphs, bimorphs, and printed elements enables differentiated mechanical responses and consistently enables and extends functional use.
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Affiliation(s)
- Joselle M McCracken
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Brian R Donovan
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
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Reyes CG, Baller J, Araki T, Lagerwall JPF. Isotropic-isotropic phase separation and spinodal decomposition in liquid crystal-solvent mixtures. SOFT MATTER 2019; 15:6044-6054. [PMID: 31225565 DOI: 10.1039/c9sm00921c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phase separation in mixtures forming liquid crystal (LC) phases is an important yet under-appreciated phenomenon that can drastically influence the behaviour of a multi-component LC. Here we demonstrate, using polarising microscopy with active cooling as well as differential scanning calorimetry, that the phase diagram for mixtures of the LC-forming compound 4'-n-pentylbiphenyl-4-carbonitrile (5CB) with ethanol is surprisingly complex. Binary mixtures reveal a broad miscibility gap that leads to phase separation between two distinct isotropic phases via spinodal decomposition or nucleation and growth. On further cooling the nematic phase enters on the 5CB-rich side, adding to the complexity. Significantly, water contamination dramatically raises the temperature range of the miscibility gap, bringing up the critical temperature for spinodal decomposition from ∼ 2 °C for the anhydrous case to >50 °C if just 3 vol% water is added to the ethanol. We support the experiments with a theoretical treatment that qualitatively reproduces the phase diagrams as well as the transition dynamics, with and without water. Our study highlights the impact of phase separation in LC-forming mixtures, spanning from equilibrium coexistence of multiple liquid phases to non-equilibrium effects due to persistent spatial concentration gradients.
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Affiliation(s)
- Catherine G Reyes
- Physics and Materials Science Research Unit, University of Luxembourg, 162a, Avenue de la Faencerie, L-1511, Luxembourg.
| | - Jörg Baller
- Physics and Materials Science Research Unit, University of Luxembourg, 162a, Avenue de la Faencerie, L-1511, Luxembourg.
| | - Takeaki Araki
- Department of Physics, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
| | - Jan P F Lagerwall
- Physics and Materials Science Research Unit, University of Luxembourg, 162a, Avenue de la Faencerie, L-1511, Luxembourg.
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