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Nam S, Jung W, Shin JH, Choi SS. Omnidirectional color wavelength tuning of stretchable chiral liquid crystal elastomers. LIGHT, SCIENCE & APPLICATIONS 2024; 13:114. [PMID: 38773092 PMCID: PMC11109264 DOI: 10.1038/s41377-024-01470-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/12/2024] [Accepted: 05/07/2024] [Indexed: 05/23/2024]
Abstract
Wavelength-tunable structural colors using stimuli-responsive materials, such as chiral liquid crystals (CLCs), have attracted increasing attention owing to their high functionality in various tunable photonic applications. Ideally, on-demand omnidirectional wavelength control is highly desirable from the perspective of wavelength-tuning freedom. However, despite numerous previous research efforts on tunable CLC structural colors, only mono-directional wavelength tuning toward shorter wavelengths has been employed in most studies to date. In this study, we report the ideally desired omnidirectional wavelength control toward longer and shorter wavelengths with significantly improved tunability over a broadband wavelength range. By using areal expanding and contractive strain control of dielectric elastomer actuators (DEAs) with chiral liquid crystal elastomers (CLCEs), simultaneous and omnidirectional structural color-tuning control was achieved. This breakthrough in omnidirectional wavelength control enhances the achievable tuning freedom and versatility, making it applicable to a broad range of high-functional photonic applications.
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Affiliation(s)
- Seungmin Nam
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Wontae Jung
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Jun Hyuk Shin
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Su Seok Choi
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
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2
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de Castro LC, Engels TAP, Oliveira ON, Schenning APHJ. Sticky Multicolor Mechanochromic Labels. ACS APPLIED MATERIALS & INTERFACES 2024; 16:14144-14151. [PMID: 38448425 PMCID: PMC10958449 DOI: 10.1021/acsami.3c19420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/14/2024] [Accepted: 02/23/2024] [Indexed: 03/08/2024]
Abstract
Sticky-colored labels are an efficient way to communicate visual information. However, most labels are static. Here, we propose a new category of dynamic sticky labels that change structural colors when stretched. The sticky mechanochromic labels can be pasted on flexible surfaces such as fabric and rubber or even on brittle materials. To enhance their applicability, we demonstrate a simple method for imprinting structural color patterns that are either always visible or reversibly revealed or concealed upon mechanical deformation. The mechanochromic patterns are imprinted with a photomask during the ultraviolet (UV) cross-linking of acrylate-terminated cholesteric liquid crystal oligomers in a single step at room temperature. The photomask locally controls the cross-linking degree and volumetric response of the cholesteric liquid crystal elastomers (CLCEs). A nonuniform thickness change induced by the Poisson's ratio contrast between the pattern and the surrounding background might lead to a color-separation effect. Our sticky multicolor mechanochromic labels may be utilized in stress-strain sensing, building environments, smart clothing, security labels, and decoration.
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Affiliation(s)
- Lucas
D. C. de Castro
- São
Carlos Institute of Physics, University
of São Paulo, São
Carlos 13566-590, SP, Brazil
- Laboratory
of Stimuli-responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology, Eindhoven5612 MB, The Netherlands
| | - Tom A. P. Engels
- Processing
and Performance of Materials, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands
| | - Osvaldo N. Oliveira
- São
Carlos Institute of Physics, University
of São Paulo, São
Carlos 13566-590, SP, Brazil
| | - Albert P. H. J. Schenning
- Laboratory
of Stimuli-responsive Functional Materials and Devices (SFD), Department
of Chemical Engineering and Chemistry, Eindhoven
University of Technology, Eindhoven5612 MB, The Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, Eindhoven 5612 MB, The Netherlands
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3
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Saeed MH, Choi MY, Kim K, Lee JH, Kim K, Kim D, Kim SU, Kim H, Ahn SK, Lan R, Na JH. Electrostatically Powered Multimode Liquid Crystalline Elastomer Actuators. ACS APPLIED MATERIALS & INTERFACES 2023; 15:56285-56292. [PMID: 37991738 DOI: 10.1021/acsami.3c13140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Soft actuators based on liquid crystalline elastomers (LCEs) are captivating significant interest because of their unique properties combining the programmable liquid crystalline molecular order and elasticity of polymeric materials. For practical applications, the ability to perform multimodal shape changes in a single LCE actuator at a subsecond level is a bottleneck. Here, we fabricate a monodomain LCE powered by electrostatic force, which enables fast multidirectional bending, oscillation, rotation, and complex actuation with a high degree of freedom. By tuning the dielectric constant and resistivity in LCE gels, a complete cycle of oscillation and rotation only takes 0.1 s. In addition, monodomain actuators exhibit anisotropic actuation behaviors that promise a more complex deployment in a potential electromechanical system. The presented study will pave the way for electrostatically controllable isothermal manipulation for a fast and multimode soft actuator.
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Affiliation(s)
- Mohsin Hassan Saeed
- Department of Electrical, Electronics and Communication Engineering Education, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Moon-Young Choi
- Department of Convergence System Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Kitae Kim
- Department of Convergence System Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jin-Hyeong Lee
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Keumbee Kim
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Dowon Kim
- Department of Electrical, Electronics and Communication Engineering Education, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Se-Um Kim
- Department of Electrical and Information Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
| | - Hyun Kim
- Advanced Materials Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Suk-Kyun Ahn
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
- Department of Polymer Science and Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Ruochen Lan
- Institute of Advanced Materials, Jiangxi Normal University, Nanchang 330022, China
| | - Jun-Hee Na
- Department of Electrical, Electronics and Communication Engineering Education, Chungnam National University, Daejeon 34134, Republic of Korea
- Department of Convergence System Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
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Wang HQ, Tang Y, Huang ZY, Wang FZ, Qiu PF, Zhang X, Li CH, Li Q. A Dual-Responsive Liquid Crystal Elastomer for Multi-Level Encryption and Transient Information Display. Angew Chem Int Ed Engl 2023; 62:e202313728. [PMID: 37818673 DOI: 10.1002/anie.202313728] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 10/12/2023]
Abstract
Information security has gained increasing attention in the past decade, leading to the development of advanced materials for anti-counterfeiting, encryption and instantaneous information display. However, it remains challenging to achieve high information security with simple encryption procedures and low-energy stimuli. Herein, a series of strain/temperature-responsive liquid crystal elastomers (LCEs) are developed to achieve dual-modal, multi-level information encryption and real-time, rewritable transient information display. The as-prepared polydomain LCEs can change from an opaque state to a transparent state under strain or temperature stimuli, with the transition strains or temperatures highly dependent on the concentration of long-chain flexible spacers. Information encrypted by different LCE inks can be decrypted under specific strains or temperatures, leading to multi-level protection of information security. Furthermore, with the combination of the phase transition of polydomain LCEs and the photothermal effect of multi-walled carbon nanotubes (MWCNTs), we achieved a repeatable transient information display by using near-infrared (NIR) light as a pen for writing. This study provides new insight into the development of advanced encryption materials with versatility and high security for broad applications.
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Affiliation(s)
- Hong-Qin Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Yuqi Tang
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, 211189, Nanjing, China
| | - Zi-Yang Huang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Fang-Zhou Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Peng-Fei Qiu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Xinfang Zhang
- Materials Science Graduate Program, Kent State University, 44242, Kent, Ohio, USA
| | - Cheng-Hui Li
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210023, Nanjing, China
| | - Quan Li
- Institute of Advanced Materials and School of Chemistry and Chemical Engineering, Southeast University, 211189, Nanjing, China
- Materials Science Graduate Program, Kent State University, 44242, Kent, Ohio, USA
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Shioda N, Kobayashi R, Katsura S, Imai H, Fujii S, Oaki Y. A highly sensitive friction-imaging device based on cascading stimuli responsiveness. MATERIALS HORIZONS 2023; 10:2237-2244. [PMID: 37006126 DOI: 10.1039/d3mh00188a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Imaging and measurement of friction forces are required in a variety of fields. If the friction forces originating from the motions of professionals are quantitatively analyzed, the data can be applied to a motion-copying system by a robot. However, weak friction forces have not been visualized and quantified using conventional sensing materials and devices because of their low sensitivity. Here we present a highly sensitive friction-imaging device based on the cascading responses of stimuli-responsive materials, namely polydiacetylene (PDA) and dry liquid (DL). Weak friction forces disrupt the DL, which is composed of liquid droplets surrounded by solid particles. The outflowing liquid under chemical stress changes the color of PDA. The cascading responses enable colorimetric imaging and measurement of weak friction forces in the range of 0.006-0.080 N. Furthermore, the device visualizes the force distribution of handwriting in calligraphy depending on the individual characteristics of an expert, a practician, and a beginner. A high-sensitivity friction-imaging device can be used to understand various motions.
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Affiliation(s)
- Nano Shioda
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Ryotaro Kobayashi
- Department of System Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Seiichiro Katsura
- Department of System Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Hiroaki Imai
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Syuji Fujii
- Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585, Japan.
| | - Yuya Oaki
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
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Zhang H, Chen H, Lee JH, Kim E, Chan KY, Venkatesan H, Shen X, Yang J, Kim JK. Mechanochromic Optical/Electrical Skin for Ultrasensitive Dual-Signal Sensing. ACS NANO 2023; 17:5921-5934. [PMID: 36920071 DOI: 10.1021/acsnano.3c00015] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Following earlier research efforts dedicated to the realization of multifunctional sensing, recent developments of artificial skins endeavor to go beyond human sensory functions by integrating interactive visualization of strain and pressure stimuli. Inspired by the microcracked structure of spider slit organs and the mechanochromic mechanism of chameleons, this work aims to design a flexible optical/electrical skin (OE-skin) capable of responding to complex stimuli with interactive feedback of human-readable structural colors. The OE-skin consists of an ionic electrode combined with an elastomer dielectric layer, a chromotropic layer containing photonic crystals and a conductive carbon nanotube/MXene layer. The electrode/dielectric layers function as a capacitive pressure sensor. The mechanochromic photonic crystals of ferroferric oxide-carbon magnetic arrays embedded in the gelatin/polyacrylamide stretchable hydrogel film perceive strain and pressure stimuli with bright color switching outputs in the full visible spectrum. The underlying microcracked conductive layer is devoted to ultrasensitive strain sensing with a gauge factor of 191.8. The multilayered OE-skin delivers an ultrafast, accurate response for capacitive pressure sensing with a detection limit of 75 Pa and long-term stability of 5000 cycles, while visualizing complex deformations in the form of high-resolution spatial colors. These findings offer deep insights into the rational design of OE-skins as multifunctional sensing devices.
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Affiliation(s)
- Heng Zhang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Haomin Chen
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Jeng-Hun Lee
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Eunyoung Kim
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Kit-Ying Chan
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Department of Aeronautical and Aviation Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, China
| | - Harun Venkatesan
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Department of Aeronautical and Aviation Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, China
| | - Xi Shen
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Department of Aeronautical and Aviation Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, China
| | - Jinglei Yang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen 518048, China
| | - Jang-Kyo Kim
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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