1
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Xu T, Han Y, Ni Y, Chi C. Oxindolyl-Based Radicals with Tunable Mechanochromic and Thermochromic Behavior. Angew Chem Int Ed Engl 2025; 64:e202414533. [PMID: 39248630 DOI: 10.1002/anie.202414533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 09/07/2024] [Accepted: 09/08/2024] [Indexed: 09/10/2024]
Abstract
Organic radicals based dynamic covalent chemistry is promising in preparing stimuli-responsive chromic materials, due to their simplicity of dissociation/association, accompanied with distinct color changes during the process. However, suitable organic radicals for dynamic covalent chemistry have not been widely explored yet. Herein, a series of oxindolyl-based mono-radicals (OxRs) with different substituents were successfully synthesized and studied systematically as potential building blocks for stimuli-responsive chromic materials. These OxRs would dimerize spontaneously to form their corresponding dimers. The structures of dimers were unambiguously confirmed through low-temperature 1H NMR and single-crystal X-ray diffraction analyses. Dynamic interconversion between monomers and dimers was achieved by reversible cleavage and recovery of the σ-bond upon soft external stimuli (temperature, pressure, and solvent polarity), accompanied by significant color changes. It is interesting that the stability of the mono-radical could be tuned through changing different substituents, and consequently altering the bond dissociation energy of the dynamic covalent bond between monomers. These new OxRs characterized by appreciable properties are entitled to more opportunities in developing mechanochromic and thermochromic materials, where their responsiveness to stimuli can be readily controlled by the substituents adhered.
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Affiliation(s)
- Tingting Xu
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Yi Han
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Yong Ni
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Chunyan Chi
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
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2
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Hertel R, Raisch M, Walter M, Reiter G, Sommer M. Mechanistically Different Mechanochromophores Enable Calibration and Validation of Molecular Forces in Glassy Polymers and Elastomeric Networks. Angew Chem Int Ed Engl 2024; 63:e202409369. [PMID: 39136230 PMCID: PMC11586691 DOI: 10.1002/anie.202409369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Indexed: 10/18/2024]
Abstract
Sterically distorted donor-acceptor π-systems, termed DA springs, can be progressively planarized under mechanical load causing a bathochromic shift of the photoluminescence (PL) spectrum. By combining theory and experiment, we here use a simple linear force calibration for two different conformational mechanochromophores to determine molecular forces in polymers from the mechanochromic shift in PL wavelength during multiple uniaxial tensile tests. Two systems are used, i) a highly entangled linear glassy polyphenylene and ii) a covalent elastomeric polydimethylsiloxane network. The mean forces estimated by this method are validated using known threshold forces for the mechanochemical ring-opening reactions of two different spiropyran force probes. The agreement between both approaches underlines that these DA springs provide the unique opportunity for the online monitoring of local molecular forces present in diverse polymer matrices.
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Affiliation(s)
- Raphael Hertel
- Department of Polymer ChemistryInstitute for ChemistryChemnitz University of TechnologyStr. der Nationen 6209111ChemnitzGermany
| | - Maximilian Raisch
- Department of Polymer ChemistryInstitute for ChemistryChemnitz University of TechnologyStr. der Nationen 6209111ChemnitzGermany
| | - Michael Walter
- FIT Freiburg Center for Interactive Materials and Bioinspired TechnologiesAlbert-Ludwig-University of FreiburgGeorges-Köhler-Allee 10579110FreiburgGermany
| | - Günter Reiter
- Institute of PhysicsAlbert-Ludwig-University of FreiburgHermann-Herder-Str. 379104FreiburgGermany
| | - Michael Sommer
- Department of Polymer ChemistryInstitute for ChemistryChemnitz University of TechnologyStr. der Nationen 6209111ChemnitzGermany
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3
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Chau AL, Karnaukh KM, Maskiewicz I, Read de Alaniz J, Pitenis AA. Photoresponsive hydrogel friction. SOFT MATTER 2024; 20:7227-7236. [PMID: 39225393 DOI: 10.1039/d4sm00677a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Photoresponsive hydrogels are an emerging class of stimuli-responsive materials that exhibit changes in physical or chemical properties in response to light. Previous investigations have leveraged photothermal mechanisms to achieve reversible changes in hydrogel friction, although few have focused on photochemical means. To date, the tribological properties of photoswitchable hydrogels (e.g., friction and lubrication) have remained underexplored. In this work, we incorporated photoresponsive methoxy-spiropyran-methacrylate monomers (methoxy-SP-MA) into a hydrogel network to form a copolymerized system of poly(N-isopropylacrylamide-co-2-acrylamido-2-methylpropane sulfonic acid-co-methoxy-spiropyran-methacrylate) (p(NIPAAm-co-AMPS-co-SP)). We demonstrated repeatable photoresponsive changes to swelling, friction, and stiffness over three light cycles. Our findings suggest that volume changes driven by the decreased hydrophilicity of the methoxy-SP-MA upon light irradiation are responsible for differences in the mechanical and tribological properties of our photoresponsive hydrogels. Our results could inform future designs of photoswitchable hydrogels for applications ranging from biomedical applications to soft robotics.
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Affiliation(s)
- Allison L Chau
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Kseniia M Karnaukh
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Ian Maskiewicz
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Javier Read de Alaniz
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Angela A Pitenis
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA, USA.
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4
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Tang C. Fundamental Aspects of Stretchable Mechanochromic Materials: Fabrication and Characterization. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3980. [PMID: 39203158 PMCID: PMC11355797 DOI: 10.3390/ma17163980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 08/08/2024] [Accepted: 08/08/2024] [Indexed: 09/03/2024]
Abstract
Mechanochromic materials provide optical changes in response to mechanical stress and are of interest in a wide range of potential applications such as strain sensing, structural health monitoring, and encryption. Advanced manufacturing such as 3D printing enables the fabrication of complex patterns and geometries. In this work, classes of stretchable mechanochromic materials that provide visual color changes when tension is applied, namely, dyes, polymer dispersed liquid crystals, liquid crystal elastomers, cellulose nanocrystals, photonic nanostructures, hydrogels, and hybrid systems (combinations of other classes) are reviewed. For each class, synthesis and processing, as well as the mechanism of color change are discussed. To enable materials selection across the classes, the mechanochromic sensitivity of the different classes of materials are compared. Photonic systems demonstrate high mechanochromic sensitivity (Δnm/% strain), large dynamic color range, and rapid reversibility. Further, the mechanochromic behavior can be predicted using a simple mechanical model. Photonic systems with a wide range of mechanical properties (elastic modulus) have been achieved. The addition of dyes to photonic systems has broadened the dynamic range, i.e., the strain over which there is an optical change. For applications in which irreversible color change is desired, dye-based systems or liquid crystal elastomer systems can be formulated. While many promising applications have been demonstrated, manufacturing uniform color on a large scale remains a challenge. Standardized characterization methods are needed to translate materials to practical applications. The sustainability of mechanochromic materials is also an important consideration.
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Affiliation(s)
- Christina Tang
- Chemical and Life Science Engineering Department, Virginia Commonwealth University, Richmond, VA 23284, USA
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5
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Guo Y, An X, Qian X. Hydrochromic and piezochromic dual-responsive optical film derived from poloxamer and ethyl cellulose for visual fingerprints identification. Int J Biol Macromol 2024; 270:132377. [PMID: 38759412 DOI: 10.1016/j.ijbiomac.2024.132377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 04/30/2024] [Accepted: 05/12/2024] [Indexed: 05/19/2024]
Abstract
Developing new materials that could identify fingerprint using the naked eye and observe the level 3 microscopic details is challenging. Here, we designed a novel hydrochromic and piezochromic dual-responsive optical film, which achieved the visual transparency transition. The performances of hydrochromic and piezochromic responses from high transparency to opaque whiteness were attributed to the introduction of poloxamer. The hygroscopic swelling of the disordered micelles led to light scattering, causing the hydrochromic response. The piezochromic response may be ascribed to the microcracks in the fragments of poloxamer crystals, which changed the refractive index of light. The fascinating combination of hydrochromic and piezochromic response was effectively applied in fingerprint identification. Hydrochromic response accurately recognized sweat pores, and piezochromic response could gradually reveal the ridges and valleys according to the different color of imprinted fingerprints. The film could identify fake fingerprints based on the differences in sweat pores between fake fingerprints and living fingers. More importantly, the film could easily detected not only the clear ridges but also the detailed sweat pores using the naked eye, indicating that the film has profound research significance in fingerprint analysis and liveness fingerprint detection.
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Affiliation(s)
- Yuqian Guo
- Research Division for Sustainable Papermaking & Advanced Materials, Key Laboratory of Biobased Material Science & Technology (Ministry of Education), Northeast Forestry University, Harbin 150040, China
| | - Xianhui An
- Research Division for Sustainable Papermaking & Advanced Materials, Key Laboratory of Biobased Material Science & Technology (Ministry of Education), Northeast Forestry University, Harbin 150040, China
| | - Xueren Qian
- Research Division for Sustainable Papermaking & Advanced Materials, Key Laboratory of Biobased Material Science & Technology (Ministry of Education), Northeast Forestry University, Harbin 150040, China.
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6
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Zhu G, Zhang Q, Yu T, Chen J, Hu R, Yang G, Zeng Y, Li Y. Multiple Force-Triggered Downconverted and Upconverted Emission in Polymers Containing Diels-Alder Adducts. Chem Asian J 2024; 19:e202301147. [PMID: 38334040 DOI: 10.1002/asia.202301147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/04/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Fluorescent mechanophores can indicate the deformation or damage in polymers. The development of mechanophores with multi-triggered response is of great interest. Herein, Diels-Alder (DA) adducts are incorporated into linear poly(methyl acrylate) PMA-BA and network poly(hexyl methacrylate) (PHMA) as mechanophores to detect the stress caused by ultrasound, freezing, and compression. The DA mechanophores undergo retro-DA reaction to release 9-styrylanthracene chromophore upon applying force, resulting in cyan fluorescence. The dissociation ratio of the DA mechanophore after pulsed ultrasonication of PMA-BA solution for 240 minutes is estimated to be 52 % by absorption spectra and 1H NMR. Additionally, the rate constant of mechanical cleavage is calculated to be 1.2×10-4 min-1⋅kDa-1 with the decrease in molecular weight from 69 to 22 kDa measured by gel permeation chromatography. Freezing of PHMA gels as well as compression of PHMA bulk samples turn-on the DA mechanophores, revealing the microscale fracture. Photon upconversion responses toward various force stimuli are also achieved in both polymer solutions and bulk samples by doping platinum octaethylporphyrin (PtOEP) or palladium meso-tetraphenyltetrabenzoporphyrin (PdTPTBP) sensitizers with multiple excitation wavelengths.
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Affiliation(s)
- Guohua Zhu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Qiaoyu Zhang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Tianjun Yu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jinping Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Rui Hu
- Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Guoqiang Yang
- Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Yi Zeng
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Yi Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Science, Beijing, 100049, China
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7
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Imato K, Ishii A, Kaneda N, Hidaka T, Sasaki A, Imae I, Ooyama Y. Thermally Stable Photomechanical Molecular Hinge: Sterically Hindered Stiff-Stilbene Photoswitch Mechanically Isomerizes. JACS AU 2023; 3:2458-2466. [PMID: 37772185 PMCID: PMC10523368 DOI: 10.1021/jacsau.3c00213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 09/30/2023]
Abstract
Molecular photoswitches are extensively used as molecular machines because of the small structures, simple motions, and advantages of light including high spatiotemporal resolution. Applications of photoswitches depend on the mechanical responses, in other words, whether they can generate motions against mechanical forces as actuators or can be activated and controlled by mechanical forces as mechanophores. Sterically hindered stiff stilbene (HSS) is a promising photoswitch offering large hinge-like motions in the E/Z isomerization, high thermal stability of the Z isomer, which is relatively unstable compared to the E isomer, with a half-life of ca. 1000 years at room temperature, and near-quantitative two-way photoisomerization. However, its mechanical response is entirely unexplored. Here, we elucidate the mechanochemical reactivity of HSS by incorporating one Z or E isomer into the center of polymer chains, ultrasonicating the polymer solutions, and stretching the polymer films to apply elongational forces to the embedded HSS. The present study demonstrated that HSS mechanically isomerizes only in the Z to E direction and reversibly isomerizes in combination with UV light, i.e., works as a photomechanical hinge. The photomechanically inducible but thermally irreversible hinge-like motions render HSS unique and promise unconventional applications differently from existing photoswitches, mechanophores, and hinges.
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Affiliation(s)
- Keiichi Imato
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Akira Ishii
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Naoki Kaneda
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Taichi Hidaka
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Ayane Sasaki
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Ichiro Imae
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
| | - Yousuke Ooyama
- Applied Chemistry
Program,
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima 739-8527, Japan
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8
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Lai Y, Li J, Chen M, Wu Y, Zhang Y, Zhao X, Chen Z. Multicolor Mechanochromic Epoxy Thermosets That Recognize the Intensity, Type, and Duration of Mechanical Stimulation. Macromol Rapid Commun 2023; 44:e2200821. [PMID: 36479907 DOI: 10.1002/marc.202200821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/17/2022] [Indexed: 12/13/2022]
Abstract
Mechanochromic polymers that exhibit multiple color changes under external mechanical stimulation show great potential for sensor applications. Herein, an epoxy thermoset that can reveal the intensity, type, and duration of mechanical stimulation via a combination of disulfide (DS) and rhodamine (Rh) mechanochromophores is reported. A unique multicolor transition occurs upon ball mill or manual grinding because of the different activation energies of DS and Rh. The epoxy changes color depending on the ball mill grinding duration. Simultaneous activation occurs with a mechanochromic time lag between DS and Rh, and the collision energy strongly affects the relative intensity. A more dramatic multicolor response is observed using a mortar and pestle, as sequential activation occurs upon gentle and strong grinding. Various types of mechanical stimulation can cause different aggregates of the activated Rh moiety and vary the relative mechanosensitivities of Rh and DS, which lead to a different color response.
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Affiliation(s)
- Yingsheng Lai
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Jiajun Li
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Mao Chen
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Yeping Wu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Yinyu Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Xiuli Zhao
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Zhongtao Chen
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
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9
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Watabe T, Otsuka H. Swelling-induced Mechanochromism in Multinetwork Polymers. Angew Chem Int Ed Engl 2023; 62:e202216469. [PMID: 36524463 DOI: 10.1002/anie.202216469] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/06/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
We report a novel and versatile approach to achieving swelling-induced mechanochemistry using a multinetwork (MN) strategy that enables polymer networks to repeatedly swell with monomers and solvents. The isotropic expansion of the first network (FN) provides sufficient force to drive the mechanochemical scission of a radical-based mechanophore, difluorenylsuccinonitrile (DFSN). Although prompt recombination generally occurs in such highly mobile environments, the resulting pink radicals are kinetically stabilized in the gels, probably due to limited diffusion in the extended polymer chains. Moreover, the DFSN embedded in the isotropically strained chain exhibits increased thermal reactivity, which can be reasonably explained by an entropic contribution of the FN to the dissociation. The utility of the MN polymers is demonstrated not only in terms of swelling-force-induced network modification, but also in the context of tunable reactivity of the dissociative unit through proper design of the hierarchical network architecture.
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Affiliation(s)
- Takuma Watabe
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Hideyuki Otsuka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.,Living Systems Materialogy (LiSM) Research Group, International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan
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10
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Ono N, Seishima R, Okabayashi K, Imai H, Fujii S, Oaki Y. Stimuli-Responsive Sponge for Imaging and Measuring Weak Compression Stresses. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206097. [PMID: 36507554 PMCID: PMC9875629 DOI: 10.1002/advs.202206097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Imaging and measuring compression stresses secure a safe and healthy life. Compression stresses in kPa range are not easily detected by conventional mechanoresponsive materials because microscopic molecular motion of the chromophores is not induced by such weak stresses. Moreover, imaging of the stress distribution is not achieved so far. The present study shows a sponge device combining two stimuli-responsive materials, a capsule releasing interior liquid and color-changing polymer in responses to compression stress and chemical stimulus, respectively. The stimuli-responsive capsule is dispersed on a melamine sponge comprised of the fibers with coating the layered polydiacetylene (PDA). The application of weak compression stresses induces collapse of the capsules, outflow of the interior liquid, and subsequent irreversible color change of PDA. The cascading response in the sponge device colorimetrically enables imaging of the distribution and measuring the strength of the compression stresses in kPa range. Furthermore, the device demonstrates imaging and measuring unknown weak compression stresses applied by the irregular-shaped objects. A couple of clinical issues in surgical operation of intestine are studied using the stress-imaging sponge device. The device and its design strategy can be applied to stress imaging in a variety of fields.
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Affiliation(s)
- Nahoko Ono
- Department of Applied ChemistryFaculty of Science and TechnologyKeio University3‐14‐1 HiyoshiKohoku‐kuYokohama223–8522Japan
| | - Ryo Seishima
- Department of SurgerySchool of MedicineKeio University35 Shinanomachi, Shinjuku‐kuTokyo160–8582Japan
| | - Koji Okabayashi
- Department of SurgerySchool of MedicineKeio University35 Shinanomachi, Shinjuku‐kuTokyo160–8582Japan
| | - Hiroaki Imai
- Department of Applied ChemistryFaculty of Science and TechnologyKeio University3‐14‐1 HiyoshiKohoku‐kuYokohama223–8522Japan
| | - Syuji Fujii
- Department of Applied ChemistryFaculty of EngineeringOsaka Institute of Technology5‐16‐1 OmiyaAsahi‐kuOsaka535–8585Japan
| | - Yuya Oaki
- Department of Applied ChemistryFaculty of Science and TechnologyKeio University3‐14‐1 HiyoshiKohoku‐kuYokohama223–8522Japan
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11
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Xu B, Luo Z, Xiao R, Wang Z, Yang J. Hybrid phenol-rhodamine dye based mechanochromic double network hydrogels with tunable stress sensitivity. Macromol Rapid Commun 2022; 43:e2200580. [PMID: 35929753 DOI: 10.1002/marc.202200580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/28/2022] [Indexed: 11/06/2022]
Abstract
Mechanochromic hydrogels, which can switch their color in response to the applied external force, have shown great potential in the stress visualization and damage indication. However, the kinds of the colors in the reported mechanochromic hydrogels are limited. It is challenging to develop the mechanochromic hydrogels with new kinds of color change. Herein, we report a kind of mechanochromic double network (DN) hydrogel based on the hybrid phenol-rhodamine (HPR) mechanophore. The hydrogels turn into orange color with an emission wavelength of around 566/574 nm in response to tensile and compressive stress. The DN hydrogels show great reversibility. The color of DN hydrogels vanishes slowly after releasing the stress. The stress sensitivity can be tailored by the crosslinking density and the mechanophore concentration of the first network. In addition, the influence of the pH on the mechanochromic properties of DN hydrogels is also studied. This study provides an insightful study in tuning the stress sensitivity in the mechanochromic hydrogel, which would be beneficial for the development of the mechanochromic materials. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Bo Xu
- Key Laboratory of Aerospace Advanced Materials and Performance, Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China
| | - Zixiong Luo
- Key Laboratory of Aerospace Advanced Materials and Performance, Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China
| | - Rui Xiao
- State Key Laboratory of Fluid Power and Mechatronic Systems, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Zhijian Wang
- Key Laboratory of Aerospace Advanced Materials and Performance, Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China
| | - Jiping Yang
- Key Laboratory of Aerospace Advanced Materials and Performance, Ministry of Education, School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China
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