Abstract
Functional dyes exhibit intriguing properties in response to external stimuli related to their optical, electronic, structural, and energetic characteristics and enable unique stimuli-responsive functions in materials by collaborating with polymers, particularly when chemically incorporated into the polymer structures. As well as the structures and properties of functional dyes, polymers, assemblies, and materials, the interactions between these components are important to the functions of materials. In this review, we introduce our recent studies conducted in the past half decade on stimuli-responsive smart polymers and polymeric materials based on functional dyes that are chemically incorporated into the polymer structures, with a special focus on light, force, electric fields, and chemicals including water in a variety of external stimuli. For example, these polymers and materials offer switchable adhesion, mechanical actuation, and chemical sensing.
Similar content being viewed by others
Introduction
Functional dyes are defined as dyes that change their properties including color and luminescence in response to external stimuli and offer fascinating stimuli-responsive functions, unlike traditional dyestuffs and pigments, which just passively interact with light [1]. Chemical incorporation of functional dye molecules into polymer structures can produce stimuli-responsive polymers with unique functions that are impossible for the individual dyes or polymers and can render them self-standing and tangible materials, which are generally not constructible when using only the dye molecules. These stimuli-responsive polymers can be called “smart” or “intelligent” because the polymers behave as if they are intelligent. Physical mixing of functional dyes and polymers is an alternative for the preparation of stimuli-responsive polymeric materials but may involve phase separation, which sometimes inhibits the functions of the dyes and deteriorates the material properties of the polymers. Poly(N-isopropylacrylamide) (PNIPAAm) has a lower critical solution temperature (LCST) around the human body temperature in aqueous solutions, is recognized as the first stimulus-responsive and temperature-responsive polymer with a history of more than half a century, and is still being studied extensively [2,3,4,5,6]. Indeed, a large variety of polymers not limited to PNIPAAm have been demonstrated to achieve unique functions via the chemical incorporation of functional dye molecules in the last few decades [7,8,9,10]. A number of external stimuli are considered for the functions, such as temperature, light, force, ultrasound, electric and magnetic fields, chemicals including water, and pH (Fig. 1a). In particular, we have focused on light, force, electric fields, and chemicals. Usually, we employ conventional functional dyes or develop original functional dyes, chemically incorporate them into the main or side chains of various polymer structures, and demonstrate the functions of the single polymer chains and the microscopic or macroscopic materials after forming (Fig. 1b). To realize the desired functions in the single chains and materials, the primary, assembly, and material structures and properties must be adequately designed at all length scales from the molecular level to the macroscopic level. The present review highlights our recent studies on smart polymers and polymeric materials that offer unique functions in response to external stimuli, such as switchable adhesion, mechanical actuation, and chemical sensing, based on functional dyes installed in the polymer structures. Here, our previous studies conducted in the last half decade are divided into four sections according to the types of external stimuli, i.e., light, force, electric fields, and chemicals including water, and separately summarized along with related important works by other research groups.
a Types of external stimuli. b Experimental scheme usually employed in our study
Light-responsive systems
Photostimulation is attractive because of its advantages, including high spatiotemporal resolution, easily and precisely controllable wavelength and intensity, and no generation of chemical waste. Photoremovable protecting (caging) groups can be regarded as functional dyes that show a one-way response to light [11,12,13]. Reversible responses are possible in photoswitches, which isomerize between two or more thermodynamically (meta)stable states upon irradiation with appropriate wavelengths of light [14,15,16,17,18]. Other functional dyes can also provide reversibility, such as rotary molecular motors that generally involve four (meta)stable states [19,20,21,22,23,24,25,26], anthracene and π-conjugated enes that undergo photoinduced cycloaddition and cycloreversion [15], and excited-state chromic molecules [27]. Azobenzenes (ABs) are the most commonly used photoswitches and are characterized by large structural changes in the photoisomerization between the stable E and metastable Z isomers (Fig. 2) [28,29,30,31]. Photoisomerization is wavelength selective, i.e., the E-to-Z and Z-to-E isomerization of the unsubstituted AB proceed under irradiation with UV light at approximately 350 nm and visible light at approximately 450 nm, respectively (Fig. 3). Because both isomers absorb the excitation wavelengths, each isomerization reaches a steady state with a certain E/Z ratio called the photostationary state (PSS). Most AB derivatives except for ortho-substituted ABs and azoheteroarenes also undergo rapid thermal isomerization from the Z isomer to the E isomer even at room temperature due to their low energy barriers [28,29,30,31]. Diarylethenes (DAEs) constitute another representative family of photoswitches and feature conjugation changes in the athermal isomerization between the open and closed forms (Fig. 2) [32]. In addition to ABs and DAEs, a wide variety of photoswitches are known, including stiff stilbenes (SSs) [33], imines [34, 35], hydrazones [36,37,38,39,40], (thio)indigos [41,42,43], hemi(thio)indigos and aurones [41, 44, 45], phenylimino indolinones and iminothioindoxyls [46, 47], dihydropyrenes [48], norbornadienes [49], fulgides and fulgimides [50, 51], rhodamines [52], dihydroazulenes [53], chromenes and naphthopyrans [16], donor-acceptor Stenhouse adducts [54, 55], oxazines [56], and 1,2-diketones [57, 58], and have been incorporated into polymer structures [15, 59,60,61].
Chemical structures and isomerization of representative photoswitches. The chemical structures are drawn with typical colors of the isomers in solution
Typical photoabsorption spectra (left) and energy diagram for isomerization (right) of E and Z isomers of ABs
Spiropyrans (SPs) are also commonly used similar to ABs and DAEs (Fig. 2). Bulky and low-polarity SPs are isomerized into planar and highly polar merocyanines (MCs) by UV light irradiation, and MCs revert back to SPs by visible light irradiation or do so spontaneously at room temperature [62, 63]. The dipole moments dramatically change between 4–6 D for SPs and 14–18 D for MCs, enabling photocontrol of intriguing phenomena including LCSTs and cell adhesion [64, 65]. We utilized the large polarity changes for photoswitchable adhesives [66], which promise to contribute to material recycling for a sustainable future as complex architectures that consist of dissimilar materials are being developed in diverse fields because they allow robust bonding during use and on-demand photoinduced debonding after use with minimal damage to adherends owing to the advantages of light [67]. Previously, photoswitchable adhesives have been achieved predominantly based on photoinduced transitions between solid, glass, and liquid states [68,69,70,71,72,73], phototriggered bond formation and cleavage [74,75,76,77,78,79,80,81,82,83], and photothermal effects [84] by using functional dyes. Because the molecular polarity and related interactions between adhesives and adherend surfaces are considered the dominant factors that generate an adhesion force [85,86,87], SPs have also been employed as additives in adhesives [88,89,90] or as low-molecular-weight adhesives [91]. However, polymer adhesives with chemically incorporated SPs had never been reported. Therefore, we developed SP-containing polymer adhesives for the first time [66].
Specifically, three non-crystalline linear polymers with SPs in the side chains linked to the main chains through different lengths of alkyl spacers, PSPA-2, PSPA-6, and PSPA-10, were synthesized by free radical polymerization (Fig. 4a). The polymers had similar degrees of polymerization (DPs) but largely different glass transition temperatures (Tgs) and free volume of the side chains, which decreased and increased with increasing the spacer alkyl chain length, respectively. Thin films of the three polymers were prepared via spin coating on piranha-treated glass substrates and irradiated first with 365 nm UV light and subsequently with 525 nm visible light. The appearance and disappearance of a photoabsorption band originating from the MCs at approximately 580 nm in the UV/vis absorption spectra with purple coloration and fading (Fig. 4b) corresponded to the SP-to-MC and MC-to-SP isomerization, respectively (Fig. 4c). The spectra normalized at the SP photoabsorption maxima at approximately 340 nm revealed that the highest MC ratio was yielded in the thin film of PSPA-10, which had the largest free volume of the side chain. Furthermore, the MC-to-SP photoisomerization in the PSPA-10 thin film proceeded fastest due the largest free volume, whereas the rates of the SP-to-MC photoisomerization in the three thin films were comparable (Fig. 4d). The thermal isomerization from the MCs to the SPs was also investigated at room temperature in the dark (Fig. 4c) and found to be much slower than the photoisomerization and similar in the three thin films (Fig. 4d). These results indicate that PSPA-10 is the best polymer for a photoswitchable adhesive because of the highest (SP-to-MC) and fastest (MC-to-SP) photoconversions but the comparably slow thermal isomerization (MC-to-SP) in the thin film. Polarity changes of the three polymers were demonstrated by static water contact angles on the thin films that were spin-coated on glass substrates modified with a hydrophobic monolayer. The contact angles decreased and then increased upon 365 nm UV light and 525 nm visible light irradiation, respectively (Fig. 4e). Additionally, the longer spacer alkyl chains resulted in higher contact angles, indicating increased hydrophobicity. The SP-containing polymers were used as adhesives for the piranha-treated hydrophilic and monolayer-modified hydrophobic glass substrates (Fig. 4f). The adhesion strength, i.e., the maximum stress in the lap shear tests, repeatedly increased and subsequently decreased with 365 nm UV light and 525 nm visible light exposure, respectively, due to the generation and loss of the highly polar MCs, which strongly interacted with each other and the adherends (Fig. 4g). The debonding seemed to occur partially in the adhesive layer after UV light irradiation but completely at the adhesive–adherend interface after visible light irradiation. In other words, the debonding was switched between cohesive failure and interfacial failure. The greatest changes in adhesion strength were achieved in PSPA-10 with the hydrophilic adherends because of strong interactions between the polymer with the highest MC ratio and the hydrophilic substrates after UV light irradiation but small interactions between the most hydrophobic polymer and the hydrophilic substrates before irradiation and after visible light irradiation. Therefore, we suggested, for the first time, a guideline for developing photoswitchable polymer adhesives based on polarity changes in chemically incorporated photoswitches: high hydrophobicity of the adhesives and large free volume around the photoswitches enable significant changes in the adhesion strength particularly with hydrophilic adherends. Compared with the additive approach [88,89,90], much higher loading of SPs into polymer adhesives without phase separation was possible in our chemical incorporation approach and led to larger changes in the adhesion strength by the photoisomerization, although the adhesion strength of the low-molecular weight adhesives was unchanged upon photoirradiation [91].
a Chemical structures and information of SP-containing polymers. b Photographs of PSPA-10 thin film before and after 365 nm exposure. c Photoabsorption spectra of PSPA-10 thin film upon 365 nm irradiation for 120 s and subsequent 525 nm irradiation or during thermal isomerization at room temperature in the dark. d Time dependence of normalized absorbance at 580 nm in the 365 nm and 525 nm exposure and thermal isomerization of three thin films. e Static contact angles of the thin films before and after 365 nm irradiation for 120 s and subsequent 525 nm irradiation for 12 h (PSPA-2), 4 h (PSPA-6), or 3 h (PSPA-10) (n > 3). Photographs of water droplets on PSPA-10 thin film. f Procedure for preparation of joint samples and evaluation of adhesion strength. g Maximum stress of PSPA-10 adhesive for hydrophilic adherends before and after 365 nm irradiation for 120 s and subsequent 525 nm irradiation for 6 h and its repeatability (n = 5). Photographs of joint samples before and after irradiation and after failure. Error bars are standard deviations. Reproduced with permission from ref. [66]. Copyright 2022, American Chemical Society
Mechanoresponsive systems
Materials are universally subjected to mechanical forces, which eventually lead to failure but have rarely been utilized in a productive way. Thus, there would still be unknown interesting chemistry. Over a decade and a half, unique functions in response to mechanical forces have been reported in polymers and polymeric materials by incorporating functional dyes [92,93,94,95,96,97,98], such as self-healing [99,100,101,102,103,104,105,106,107,108,109,110,111], mechano(lumino)chromism for force and damage detection [112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140], self-strengthening [141,142,143], and other polymer reactions [144,145,146,147,148,149,150]. Additionally, the mechanoresponsive functions have been controlled by another external stimulus [106, 151,152,153]. A part of the photoswitches shown in Fig. 2 are also known to undergo isomerization under mechanical forces [154, 155]. SPs are the first photoswitches reported to be isomerized by mechanical forces [156,157,158]. Similarly, the ring opening reactions of naphthopyrans [159,160,161,162,163], rhodamines [164,165,166], and oxazines [167, 168] are mechanically induced. The Z isomer of ABs also mechanically isomerizes to the E isomer [169,170,171], although mechanoisomerization has never been observed in DAEs [153, 172,173,174,175]. Nevertheless, one isomer of each mechanoactive photoswitch is thermally unstable; therefore, the isomerization is precisely uncontrollable by mechanical means. We have focused on a new family of thermally stable photoswitches, sterically hindered SSs (HSSs) (Fig. 2) [33, 176,177,178,179], and recently reported that the E–Z isomerization of HSSs can be controlled orthogonally by photoirradiation and mechanical forces [180].
We synthesized a linear polymer with one Z isomer of an HSS photoswitch at the center of the polymer chains, Z-HSS-diPMA, by atom transfer radical polymerization of methyl acrylate from an HSS initiator with two initiating groups at both ends (Fig. 5a). The Z isomer was primarily focused on because ABs mechanically isomerize from the Z isomer to the E isomer [169,170,171], although the corresponding E isomer of the polymer, E-HSS-diPMA, was also prepared in a similar manner as a control and a standard for comparison via 1H NMR spectroscopy. First, we verified the photoisomerization of the incorporated HSS. When a tetrahydrofuran (THF) solution of the Z isomer was exposed to 405 nm visible light, the UV/vis absorption and 1H NMR spectra gradually changed, which corresponded to the Z-to-E isomerization (Fig. 5b, c). At the PSS, the Z/E ratio was 18/82. Conversely, 340 nm UV light irradiation of the 405 nm PSS solution caused the E-to-Z isomerization and provided a PSS with a Z/E ratio of 79/21, and the reversible photoisomerization was repeatedly observed. In other words, the HSS photoswitch underwent 80% two-way photoisomerization even at the center of the polymer chains, while small HSS derivatives offered 90% photoisomerization yields in both directions [177]. The mechanoisomerization of the embedded HSS was subsequently investigated. Generally, a target molecule must be incorporated into a polymer chain to be subjected to elongational forces. We employed ultrasonication of polymer solutions, a common technique in polymer mechanochemistry, which generates elongational forces along polymer chains and causes scission around the middle (Fig. 5d) [181]. UV/vis absorption and 1H NMR spectra during irradiation of the Z-HSS-diPMA (Z/E = 100/0) and 405 nm PSS (Z/E = 18/82) solutions with pulsed ultrasound for 100 min indicated that the Z-to-E isomerization proceeded in both solutions, resulting in Z/E ratios of 22/78 and 7/93, respectively (Fig. 5e, f). During the ultrasonication, the unimodal size exclusion chromatography (SEC) curves of Z-HSS-diPMA and the 405 nm PSS gradually changed to bimodal distributions, in which the new peaks corresponded to approximately one-half of the original molecular weights and indicated chain scission near the center (Fig. 5g). In contrast, only chain scission without isomerization was observed in ultrasonication of an E-HSS-diPMA solution. Additionally, the possibility of thermal isomerization in the ultrasonication-induced isomerization was excluded by a control experiment on a mixture of poly(methyl acrylate) and the Z isomer of a small HSS derivative, the results of which are similar to those observed in E-HSS-diPMA. Furthermore, alternating stimulation of Z-HSS-diPMA in solution by ultrasonication and UV light irradiation demonstrated the Z-to-E mechanical isomerization and E-to-Z photoisomerization in an orthogonal manner (Fig. 5h). Based on these results, we concluded that HSSs are the first photoswitches, mechanophores, and molecular hinges that can switch between two thermally stable states with hinge-like motions orthogonally in response to light and force. At the same time, the Z-to-E mechanoisomerization of SSs was also reported [182]. Unlike in our study, the SS photoswitches were incorporated into polymer chains by polymer reactions, probably because the unhindered reactive C=C bond undergoes side reactions in radial polymerization and olefin metathesis polymerization [180, 183].
a Chemical structures of Z-HSS-diPMA and Z-HSS-diPMA. b UV/vis absorption spectra of Z-HSS-diPMA under 405 nm and 340 nm irradiation in THF (2.00 mg mL−1). c 1H NMR spectra (500 MHz, acetone-d6) of Z-HSS-diPMA, 405 and 340 nm PSSs, and E-HSS-diPMA. d Ultrasonication and polymer chain scission in solution. e UV/vis absorption spectra and g SEC curves (refractive index (RI) signals) of Z-HSS-diPMA and 405 nm PSS under ultrasonication (US) for 100 min in THF (2.00 mg mL−1). f 1H NMR spectra (500 MHz, acetone-d6) of Z-HSS-diPMA and 405 nm PSS before and after the US. h 1H NMR spectra (500 MHz, acetone-d6) of Z-HSS-diPMA upon alternating irradiation with ultrasound (US) for 100 min and 340 nm light until PSSs in THF (2.00 mg mL–1). Reproduced with permission from ref. [180]. Copyright 2023, American Chemical Society
Electroresponsive systems
Electricity is precisely controllable and suitable for the manipulation of robots. Conventional robots consist of hard materials, such as metals, may harm humans, and therefore, are employed separately from people in factories. Nevertheless, the demand for robots in nursing care and rescue involving physical interactions with people is growing. Additionally, future robots will come into close contact with humans and integrate into daily life for some applications, including the replacement of human labor and in-body diagnosis, medical treatment, and even surgery, due to the development of the Internet of Things and artificial intelligence [184, 185]. In this context, soft robots composed of soft materials have been extensively studied [186, 187]. Their motions in response to external stimuli are produced by actuators, which should be intrinsically soft for soft robots [188]. Therefore, soft polymer actuators are indispensable particularly for small robots with complex structures and motions due to their high flexibility, deformability, adaptability, agility, dexterity, and degree of freedom [184, 185]. Previously, a countless number of soft actuators driven by electricity including electrochemical redox reactions have been reported [189]. The electrochemical soft actuators were constructed by sandwiching one of the three types of polymeric materials between two flexible electrodes: conducting polymers, dielectric elastomers, and polymer gels. However, they require a direct connection to a power supply, which limits their size, structures, and motions to large thin sheets that can be bent or extended. Based on this background, wireless electrochemical soft actuators have been developed by using bipolar electrochemistry [190,191,192,193,194,195,196,197,198,199,200,201]. While reduction and oxidation occur on each surface of two electrodes connected to a power supply in conventional electrochemistry (Fig. 6a), in bipolar electrochemistry, anodic and cathodic reactions occur simultaneously at the terminals of a conductor placed between a pair of driving electrodes without any direct electrical contact under an applied electric field in a dilute supporting electrolyte solution (Fig. 6b) [202,203,204,205,206,207,208]. The conductor is called a bipolar electrode (BPE), whose type, size, shape, and number are unrestricted. In pioneering work, bending of films and pumping with tubes were achieved based on redox reactions induced by bipolar electrochemistry, resulting uptake/release of ions and solvent in the BPE to maintain electroneutrality, and swelling/shrinking of the BPE [190,191,192,193,194,195,196,197,198,199,200,201]. However, all previously reported wireless electrochemical soft actuators employed only a combination of a conducting polymer, polypyrrole (PPy), and bipolar electrochemistry. For the development of soft robots, a wide variety of materials, mechanisms, and motions of soft actuators are undoubtedly indispensable.
a Conventional and b bipolar electrochemistry. c Redox-reversible dimerization of viologen. d Chemical structures of viologen-containing hydrogels and e their actuation by bipolar electrochemistry. Photoabsorption spectra of f viologen monomer (50 μM) and g the hydrogels before and after reduction by 50 mM Na2S2O4 for 60 min in PBS. Photographs of f monomer solutions and g 20% gel before and after the reduction. h Volume changes of the hydrogels during the reduction (n = 3) with photographs of 20% gel before and after the reduction. The error bars are standard deviations, and the scale of the measure is in millimeters. i Setup for electrochemical actuation of the hydrogels. Volume changes of millimeter-sized hydrogels upon j application of −6 V for 8 min and subsequent +6 V for 8 min and l alternating application of each voltage for 8 min. The purple and white areas indicate the application of −6 and +6 V, respectively. k Photographs of the hydrogels before and after the application of voltage. Scale bars are 500 µm. m Photographs of centimeter-sized hydrogels before and after application of −6 V for 10 min. n Plausible mechanism for electron propagation via viologen mediator. Reproduced with permission from ref. [209]. Copyright 2024, John Wiley & Sons
Therefore, we newly developed wireless electrochemical soft actuators by using bipolar electrochemistry and polymer gels, which are among the most commonly used materials in wired electrochemical soft actuators [209]. We additionally employed viologen, which reversibly forms a π-dimer via redox reactions (Fig. 6c) [210,211,212], and synthesized three hydrogels, 5% gel, 10% gel, and 20% gel, with different contents of viologen in the side chains via free radical copolymerization of acrylamide, a chemical cross-linker (1 mol%), and a viologen monomer (5, 10, or 20 mol%) (Fig. 6d) [213,214,215]. The dimerization and dissociation were expected to induce shrinkage and swelling of the hydrogels (Fig. 6e). First, we examined their response to chemical reduction using sodium dithionite (Na2S2O4) in a phosphate-buffered saline (PBS) solution. As a control experiment, the chemical reduction of the viologen monomer generated new photoabsorption bands in the UV/vis absorption spectrum with blue coloration originating from the free radical cation (Fig. 6f) [210, 216]. On the other hand, two other bands with black coloration derived from the π-dimer appeared after the chemical reduction of the hydrogels due to the close location of viologen molecules in the polymer networks, unlike in the dilute monomer solution (Fig. 6g) [210, 216]. The volume changes were also monitored during the chemical reduction. The hydrogels gradually shrank and reached equilibrium swelling states (Fig. 6h). A higher viologen content of the hydrogels corresponded to greater volume shrinkage. Immersion of the reduced hydrogels in PBS without the reductant almost restored the color and volume over several days because of oxidation by dissolved oxygen. Thus, we verified that the reduction and oxidation of the incorporated viologen caused the dimerization and dissociation and the shrinkage and swelling of the hydrogels, respectively. Then, we actuated millimeter-sized hydrogels based on bipolar electrochemistry by applying a voltage between two feeder electrodes (Fig. 6i) and observed the behavior of the hydrogels via optical microscopy. Potassium hydroquinone sulfonate (KHQS) was employed as a sacrificial reagent to complement redox reactions on the BPE. The hydrogels gradually contracted with purple coloration under −6 V and quickly swelled with fading under +6 V with the help of oxidation by dissolved oxygen (Fig. 6j, k). The volume changes of the hydrogels with higher viologen contents tended to be greater, although partly dependent on the size, shape, contact area with the BPE, and device setup. The reversible shrinkage and swelling were repeatedly observed, similar to the motions of a muscle, with gradual volume decreases, which may be due to strong interactions between the reduced viologen and oxidized KHQS (Fig. 6l). Unexpectedly, the volume changes were comparable to those caused by the chemical reduction despite the heterogeneous reactions on the BPE surfaces. Therefore, the macroscopic actuation of centimeter-sized hydrogels was also examined (Fig. 6m). A portion of the hydrogels on the BPE cathode visibly contracted with purple coloration. The viologen molecules might act as mediators to propagate electrons and reduce themselves to dimerize even far from the BPE interface (Fig. 6n) [217, 218]. Previously, viologen-containing gels have been reported to be actuated by chemical redox reactions [215, 216, 219, 220] and photoirradiation [221,222,223] but not by electrochemistry. In this study, we demonstrated for the first time not only the wireless electrochemical actuation of polymer gels but also the electrochemical actuation of viologen-containing gels.
Chemoresponsive systems
Detection and determination of chemicals harmful to humans and the environment or influential molecules for target applications are important to avoid the exposure and improve the applications. Functional dyes that interact or react with such chemicals and change their optical properties allow the easy and sensitive visual detection and even real-time monitoring. Volatile organohalogen compounds (VOHCs) are mostly harmful but indispensable in manufacturing. Therefore, functional dyes responsive to VOHCs have been developed, and a photophysical phenomenon that involves a significant hypsochromic or bathochromic effect only in halogenated solvents was termed organohalogenochromism (OHC) [224,225,226,227]. In this context, we very recently incorporated a donor–π–acceptor (D–π–A)-type pyridinium dye offering OHC into the side chains of a linear polymer and demonstrated OHC of the polymer (Fig. 7a) [228]. Moreover, thin films of the polymer were prepared and enabled the easy and reversible detection of VOHCs.
a Chemical structure and OHC in solutions and thin film of linear polymer with D–π–A-type pyridinium dye. Reproduced with permission from ref. [228]. Copyright 2024, the Royal Society of Chemistry. b Chemical structure and water visualization in solution and thin film of linear polymer with PET-based fluorescent dye. Reproduced with permission from ref. [252]. Copyright 2022, the Royal Society of Chemistry
Additionally, water significantly affects synthesis and production of chemicals, medicines, and electronics. Thus, visual detection and determination of water have been extensively studied and achieved by using functional dyes based on a variety of mechanisms, such as aggregation-induced emission, excited-state intramolecular proton transfer, Förster resonance energy transfer, intramolecular charge transfer, and photoinduced electron transfer (PET) [229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251]. We synthesized a linear polymer with a fluorescent dye that offers high sensitivity to water due to turn-on fluorescence based on PET in the side chains and developed its thin films (Fig. 7b) [252] as well as dye-doped films and dye-immobilized substrates [253,254,255]. The reversible visual detection of water was successfully demonstrated.
Conclusion
In this review, we summarized our recent studies on stimuli-responsive smart polymers and polymeric materials based on functional dyes that were chemically installed in the structures with a particular focus on the stimuli of light, force, electric fields, and chemicals including water, along with related important works of other research groups. The incorporation of functional dyes into polymers has infinite possibilities that are only limited by creativity. However, there is no example and no guideline to amplify and reflect functions of functional dyes at the molecular level to those of materials at the macroscopic level in synergy with polymers without offsetting each other. To this end, not only the structures and properties of functional dyes, polymers, assemblies, and materials but also the interactions between them must be adequately and precisely designed and constructed at all length scales. The road will be long, but this field has achieved steady progress [256,257,258,259]. We hope that the present review provides useful information and inspiration for the development.
References
Ooyama Y, Yagi S. Progress in the science of functional dyes. Singapore: Springer; 2021.
Heskins M, Guillet JE. Solution properties of Poly(N-isopropylacrylamide). J Macromol Sci A. 1968;2:1441–55.
Schild HG. Poly(N-isopropylacrylamide): experiment, theory and application. Prog Polym Sci. 1992;17:163–249.
Halperin A, Kröger M, Winnik FM. Poly(N-isopropylacrylamide) phase diagrams: fifty years of research. Angew Chem Int Ed. 2015;54:15342–67.
Shaibie NA, Ramli NA, Faizal NDFM, Srichana T, Amin MCIM. Poly(N-isopropylacrylamide)-based polymers: recent overview for the development of temperature-responsive drug delivery and biomedical applications. Macromol Chem Phys 2023;224:2300157.
Das A, Babu A, Chakraborty S, Guyse JFR V, Hoogenboom R, Maji S. Poly(N-isopropylacrylamide) and its copolymers: a review on recent advances in the areas of sensing and biosensing. Adv Funct Mater. 2024;34:2402432.
Herbert KM, Schrettl S, Rowan SJ, Weder C. 50th anniversary perspective: solid-state multistimuli, multiresponsive polymeric materials. Macromolecules. 2017;50:8845–70.
Wang S, Liu Q, Li L, Urban MW. Recent advances in stimuli-responsive commodity polymers. Macromol Rapid Commun. 2021;42:e2100054.
Png ZM, Wang C-G, Yeo JCC, Lee JJC, Surat’man NE, Tan YL, et al. Stimuli-responsive structure–property switchable polymer materials. Mol Syst Des Eng. 2023;8:1097–129.
Wang S, Urban MW. Redefining polymer science via multi-stimulus responsiveness. Chem. 2023;9:1362–77.
Klán P, Šolomek T, Bochet CG, Blanc A, Givens R, Rubina M, et al. Photoremovable protecting groups in chemistry and biology: reaction mechanisms and efficacy. Chem Rev. 2013;113:119–91.
Weinstain R, Slanina T, Kand D, Klán P. Visible-to-NIR-light activated release: from small molecules to nanomaterials. Chem Rev 2020;120:13135–272.
Josa-Culleré L, Llebaria A. In the search for photocages cleavable with visible light: an overview of recent advances and chemical strategies. ChemPhotoChem. 2021;5:296–314.
Pianowski ZL. Recent implementations of molecular photoswitches into smart materials and biological systems. Chem Eur J 2019;25:5128–44.
Lu P, Ahn D, Yunis R, Delafresnaye L, Corrigan N, Boyer C, et al. Wavelength-selective light-matter interactions in polymer science. Matter. 2021;4:2172–229.
Volarić J, Szymanski W, Simeth NA, Feringa BL. Molecular photoswitches in aqueous environments. Chem Soc Rev. 2021;50:12377–449.
Zhang Z, Wang W, O’Hagan M, Dai J, Zhang J, Tian H. Stepping out of the blue: from visible to near-IR triggered photoswitches. Angew Chem Int Ed. 2022;61:e202205758.
Leistner A, Pianowski ZL. Smart photochromic materials triggered with visible light. Eur J Org Chem. 2022;2022:e202101271.
Kassem S, Leeuwen T, van, Lubbe AS, Wilson MR, Feringa BL, Leigh DA. Artificial molecular motors. Chem Soc Rev. 2017;46:2592–621.
Roke D, Wezenberg SJ, Feringa BL. Molecular rotary motors: unidirectional motion around double bonds. Proc Natl Acad Sci USA. 2018;115:201712784.
Corra S, Curcio M, Baroncini M, Silvi S, Credi A. Photoactivated artificial molecular machines that can perform tasks. Adv Mater. 2020;32:1906064.
Zhang Q, Qu D-H, Tian H, Feringa BL. Bottom-up: can supramolecular tools deliver responsiveness from molecular motors to macroscopic materials? Matter. 2020;3:355–70.
Baroncini M, Silvi S, Credi A. Photo- and redox-driven artificial molecular motors. Chem Rev 2020;120:200–68.
Costil R, Holzheimer M, Crespi S, Simeth NA, Feringa BL. Directing coupled motion with light: a key step toward machine-like function. Chem Rev. 2021;121:13213–37.
Corra S, Curcio M, Credi A. Photoactivated artificial molecular motors. JACS Au. 2023;3:1301–13.
Sheng J, Pooler DRS, Feringa BL. Enlightening dynamic functions in molecular systems by intrinsically chiral light-driven molecular motors. Chem Soc Rev. 2023;52:5875–91.
Ohira K, Kozuka K, Kaneda N, Yamamoto M, Imato K, Ooyama Y. Photochromism of phenazine-2,3-diol derivatives through excited state intermolecular proton transfer based on keto–enol tautomerization. Org Biomol Chem. 2024;22:4077–88.
Bandara HMD, Burdette SC. Photoisomerization in different classes of azobenzene. Chem Soc Rev. 2012;41:1809–25.
Crespi S, Simeth NA, König B. Heteroaryl azo dyes as molecular photoswitches. Nat Rev Chem. 2019;3:133–46.
Gao M, Kwaria D, Norikane Y, Yue Y. Visible-light-switchable azobenzenes: molecular design, supramolecular systems, and applications. Nat Sci 2023;3:e220020.
Mukherjee A, Seyfried MD, Ravoo BJ. Azoheteroarene and diazocine molecular photoswitches: self-assembly, responsive materials and photopharmacology. Angew Chem Int Ed. 2023;62:e202304437.
Irie M, Fukaminato T, Matsuda K, Kobatake S. Photochromism of diarylethene molecules and crystals: memories, switches, and actuators. Chem Rev. 2014;114:12174–277.
Villarón D, Wezenberg SJ. Stiff-stilbene photoswitches: from fundamental studies to emergent applications. Angew Chem Int Ed. 2020;59:13192–202.
Greb L, Eichhöfer A, Lehn J. Internal C–C bond rotation in photoisomers of α-bisimines: a light-responsive two-step molecular speed regulator based on double imine photoswitching. Eur J Org Chem. 2016;2016:1243–6.
Wu J, Kreimendahl L, Tao S, Anhalt O, Greenfield JL. Photoswitchable imines: aryliminopyrazoles quantitatively convert to long-lived Z-isomers with visible light. Chem Sci. 2024;15:3872–8.
Shao B, Aprahamian I. Hydrazones as new molecular tools. Chem. 2020;6:2162–73.
Qian H, Pramanik S, Aprahamian I. Photochromic hydrazone switches with extremely long thermal half-lives. J Am Chem Soc. 2017;139:9140–3.
Shao B, Baroncini M, Qian H, Bussotti L, Donato MD, Credi A, et al. Solution and solid-state emission toggling of a photochromic hydrazone. J Am Chem Soc. 2018;140:12323–7.
Li Q, Qian H, Shao B, Hughes RP, Aprahamian I. Building strain with large macrocycles and using it to tune the thermal half-lives of hydrazone photochromes. J Am Chem Soc. 2018;140:11829–35.
Shao B, Qian H, Li Q, Aprahamian I. Structure property analysis of the solution and solid-state properties of bistable photochromic hydrazones. J Am Chem Soc. 2019;141:8364–71.
Petermayer C, Dube H. Indigoid photoswitches: visible light responsive molecular tools. Acc Chem Res. 2018;51:1153–63.
Huang C, Hecht S. A blueprint for transforming indigos to photoresponsive molecular tools. Chem Eur J. 2023;29:e202300981
Kaplan G, Seferoğlu Z, Berdnikova DV. Photochromic derivatives of indigo: historical overview of development, challenges and applications. Beilstein J Org Chem. 2024;20:228–42.
Wiedbrauk S, Dube H. Hemithioindigo—an emerging photoswitch. Tetrahedron Lett. 2015;56:4266–74.
Berdnikova DV. Aurones: unexplored visible-light photoswitches for aqueous medium. Chem Eur J 2024;30:e202304237.
Hoorens MWH, Medved’ M, Laurent AD, Donato MD, Fanetti S, Slappendel L, et al. Iminothioindoxyl as a molecular photoswitch with 100 nm band separation in the visible range. Nat Commun. 2019;10:2390.
Crespi S, Simeth NA, Donato MD, Doria S, Stindt CN, Hilbers MF, et al. Phenylimino indolinone: a green-light-responsive T-type photoswitch exhibiting negative photochromism. Angew Chem Int Ed. 2021;60:25290–5.
Mitchell RH. The metacyclophanediene-dihydropyrene photochromic π switch. Eur J Org Chem. 1999;1999:2695–703.
Hemauer F, Steinrück H, Papp C. The norbornadiene/quadricyclane pair as molecular solar thermal energy storage system: surface science investigations. ChemPhysChem. 2024;25:e202300806.
Matsushima R, Sakaguchi H. Comparison of the photochromic properties of fulgides and fulgimides. J Photochem Photobiol A Chem. 1997;108:239–45.
Copko J, Slanina T. Multiplicity-driven photochromism controls three-state fulgimide photoswitches. Chem Commun. 2024;60:3774–7.
Bar N, Chowdhury P. A brief review on advances in rhodamine b based chromic materials and their prospects. ACS Appl Electron Mater. 2022;4:3749–71.
Broman SL, Nielsen MB. Dihydroazulene: from controlling photochromism to molecular electronics devices. Phys Chem Chem Phys. 2014;16:21172–82.
Lerch MM, Szymański W, Feringa BL. The (photo)chemistry of Stenhouse photoswitches: guiding principles and system design. Chem Soc Rev. 2018;47:1910–37.
Clerc M, Sandlass S, Rifaie-Graham O, Peterson JA, Bruns N, Alaniz JRde, et al. Visible light-responsive materials: the (photo)chemistry and applications of donor–acceptor Stenhouse adducts in polymer science. Chem Soc Rev. 2023;52:8245–94.
Gulati GK, Gulati LK, Kumar S. Recent progress in multi-stimulable photochromic oxazines with their wide-ranging applications. Dyes Pigm. 2021;192:109445.
Komura M, Ogawa T, Tani Y. Room-temperature phosphorescence of a supercooled liquid: kinetic stabilisation by desymmetrisation. Chem Sci. 2021;12:14363–8.
Komura M, Sotome H, Miyasaka H, Ogawa T, Tani Y. Photoinduced crystal melting with luminescence evolution based on conformational isomerisation. Chem Sci. 2023;14:5302–8.
Boelke J, Hecht S. Designing molecular photoswitches for soft materials applications. Adv Opt Mater. 2019;7:1900404.
Goulet-Hanssens A, Eisenreich F, Hecht S. Enlightening materials with photoswitches. Adv Mater. 2020;32:1905966.
Dattler D, Fuks G, Heiser J, Moulin E, Perrot A, Yao X, et al. Design of collective motions from synthetic molecular switches, rotors, and motors. Chem Rev. 2020;120:310–433.
Klajn R. Spiropyran-based dynamic materials. Chem Soc Rev. 2014;43:148–84.
Kortekaas L, Browne WR. The evolution of spiropyran: fundamentals and progress of an extraordinarily versatile photochrome. Chem Soc Rev. 2019;48:3406–24.
Nagata K, Kurebayashi T, Imato K, Takeda N. Photoresponsive fiber scaffolds with a core–sheath nanostructure for regulating cell behaviors. J Mater Chem B. 2018;6:2052–6.
Imato K, Nagata K, Watanabe R, Takeda N. Cell adhesion control by photoinduced LCST shift of PNIPAAm-based brush scaffolds. J Mater Chem B. 2020;8:2393–9.
Imato K, Momota K, Kaneda N, Imae I, Ooyama Y. Photoswitchable adhesives of spiropyran polymers. Chem Mater. 2022;34:8289–96.
Hohl DK, Weder C. De)bonding on demand with optically switchable adhesives. Adv Opt Mater. 2019;7:1900230
Akiyama H, Yoshida M. Photochemically reversible liquefaction and solidification of single compounds based on a sugar alcohol scaffold with multi azo-arms. Adv Mater. 2012;24:2353–6.
Zhou H, Xue C, Weis P, Suzuki Y, Huang S, Koynov K, et al. Photoswitching of glass transition temperatures of azobenzene-containing polymers induces reversible solid-to-liquid transitions. Nat Chem. 2017;9:145–51.
Xu W, Sun S, Wu S. Photoinduced reversible solid-to-liquid transitions for photoswitchable. Mater Angew Chem Int Ed. 2019;58:9712–40.
Xu G, Li S, Liu C, Wu S. Photoswitchable adhesives using azobenzene-containing materials. Chem Asian J. 2020;15:547–54.
Hu J, Song T, Yu M-M, Yu H. Optically controlled solid-to-liquid phase transition materials based on azo compounds. Chem Mater. 2023;35:4621–48.
Imato K, Kaneda N, Ooyama Y. Recent progress in photoinduced transitions between the solid, glass, and liquid states based on molecular photoswitches. Polym J. 2024;56:269–82.
Inui T, Sato E, Matsumoto A. Pressure-sensitive adhesion system using acrylate block copolymers in response to photoirradiation and postbaking as the dual external stimuli for on-demand dismantling. ACS Appl Mater Interfaces. 2012;4:2124–32.
Asadirad AM, Boutault S, Erno Z, Branda NR. Controlling a polymer adhesive using light and a molecular switch. J Am Chem Soc 2014;136:3024–7.
Saito S, Nobusue S, Tsuzaka E, Yuan C, Mori C, Hara M, et al. Light-melt adhesive based on dynamic carbon frameworks in a columnar liquid-crystal phase. Nat Commun. 2016;7:12094.
Oka M, Takagi H, Miyazawa T, Waymouth RM, Honda S. Photocleavable regenerative network materials with exceptional and repeatable viscoelastic manipulability. Adv Sci. 2021;8:2101143.
Aizawa M, Akiyama H, Matsuzawa Y. Dismantlable adhesion interface featuring a thermo/photocleavable molecular layer. Adv Eng Mater. 2022;24:2100823.
Aizawa M, Akiyama H, Yamamoto T, Matsuzawa Y. Photo-and heat-induced dismantlable adhesion interfaces prepared by layer-by-layer deposition. Langmuir. 2023;39:2771–8.
Kaneko T, Russell GM, Kawano Y, Masai H, Terao J. Fabrication of photoprocessable materials via photopolymerization using an acid-induced photocleavable platinum-acetylide crosslinker. Angew Chem Int Ed. 2023;62:e202305374.
Matsumoto A. Development of heat-responsive adhesive materials that are stable during use and quickly deteriorate during dismantling. Polym J. 2024;56:223–47.
Masai H, Nakagawa T, Terao J. Recent progress in photoreactive crosslinkers in polymer network materials toward advanced photocontrollability. Polym J. 2024;56:297–307.
Aizawa M, Akiyama H, Matsuzawa Y, Shishido A. Reusable dismantlable adhesion interfaces induced by photodimerization and thermo/photocleavage reactions. Polym J. 2024;56:401–8.
Heinzmann C, Coulibaly S, Roulin A, Fiore GL, Weder C. Light-induced bonding and debonding with supramolecular adhesives. ACS Appl Mater Interfaces. 2014;6:4713–9.
Kinloch AJ. The science of adhesion. J Mater Sci. 1980;15:2141–66.
Raos G, Zappone B. Polymer adhesion: seeking new solutions for an old problem. Macromolecules. 2021;54:10617–44.
Cheng B, Yu J, Arisawa T, Hayashi K, Richardson JJ, Shibuta Y, et al. Ultrastrong underwater adhesion on diverse substrates using non-canonical phenolic groups. Nat Commun. 2022;13:1892.
Tannouri P, Arafeh KM, Krahn JM, Beaupré SL, Menon C, Branda NR. A photoresponsive biomimetic dry adhesive based on doped PDMS microstructures. Chem Mater. 2014;26:4330–3.
Mostafavi SH, Tong F, Dugger TW, Kisailus D, Bardeen CJ. Noncovalent photochromic polymer adhesion. Macromolecules. 2018;51:2388–94.
Gately TJ, Li W, Mostafavi SH, Bardeen CJ. Reversible adhesion switching using spiropyran photoisomerization in a high glass transition temperature polymer. Macromolecules. 2021;54:9319–26.
Zhang L, Deng Y, Xie C, Wu Z. Disordered low molecular weight spiropyran exhibiting photoregulated adhesion ability. Chem Eur J. 2022;28:e202200245.
Caruso MM, Davis DA, Shen Q, Odom SA, Sottos NR, White SR, et al. Mechanically-induced chemical changes in polymeric materials. Chem Rev. 2009;109:5755–98.
Li J, Nagamani C, Moore JS. Polymer mechanochemistry: from destructive to productive. Acc Chem Res. 2015;48:2181–90.
Willis-Fox N, Rognin E, Aljohani TA, Daly R. Polymer Mechanochemistry: Manufacturing Is Now a Force to Be Reckoned With. Chem. 2018;4:2499–537.
Imato K, Otsuka H. Reorganizable and stimuli-responsive polymers based on dynamic carbon–carbon linkages in diarylbibenzofuranones. Polymer. 2018;137:395–413.
Deneke N, Rencheck ML, Davis CS. An engineer’s introduction to mechanophores. Soft Matter. 2020;16:6230–52.
Chen Y, Mellot G, Luijk D, van, Creton C, Sijbesma RP. Mechanochemical tools for polymer materials. Chem Soc Rev. 2021;50:4100–40.
Mu Q, Hu J. Polymer mechanochemistry: from single molecule to bulk material. Phys Chem Chem Phys. 2024;26:679–94.
Nakahata M, Takashima Y, Yamaguchi H, Harada A. Redox-responsive self-healing materials formed from host–guest polymers. Nat Commun. 2011;2:511.
Imato K, Nishihara M, Kanehara T, Amamoto Y, Takahara A, Otsuka H. Self-healing of chemical gels cross-linked by diarylbibenzofuranone-based trigger-free dynamic covalent bonds at room temperature. Angew Chem Int Ed. 2012;51:1138–42.
Imato K, Ohishi T, Nishihara M, Takahara A, Otsuka H. Network reorganization of dynamic covalent polymer gels with exchangeable diarylbibenzofuranone at ambient temperature. J Am Chem Soc. 2014;136:11839–45.
Harada A, Takashima Y, Nakahata M. Supramolecular polymeric materials via cyclodextrin–guest interactions. Acc Chem Res. 2014;47:2128–40.
Imato K, Takahara A, Otsuka H. Self-healing of a cross-linked polymer with dynamic covalent linkages at mild temperature and evaluation at macroscopic and molecular levels. Macromolecules. 2015;48:5632–9.
Yang Y, Ding X, Urban MW. Chemical and physical aspects of self-healing materials. Prog Polym Sci. 2015;49:34–59.
An SY, Arunbabu D, Noh SM, Song YK, Oh JK. Recent strategies to develop self-healable crosslinked polymeric networks. Chem Commun. 2015;51:13058–70.
Fuhrmann A, Göstl R, Wendt R, Kötteritzsch J, Hager MD, Schubert US, et al. Conditional repair by locally switching the thermal healing capability of dynamic covalent polymers with light. Nat Commun. 2016;7:13623.
Takahashi A, Goseki R, Otsuka H. Thermally adjustable dynamic disulfide linkages mediated by highly air-stable 2,2,6,6-tetramethylpiperidine-1-sulfanyl (TEMPS) radicals. Angew Chem Int Ed. 2017;56:2016–21.
Takahashi A, Goseki R, Ito K, Otsuka H. Thermally healable and reprocessable Bis(hindered amino)disulfide-cross-linked polymethacrylate networks. ACS Macro Lett. 2017;6:1280–4.
Tsuruoka A, Takahashi A, Aoki D, Otsuka H. Fusion of different crosslinked polymers based on dynamic disulfide exchange. Angew Chem Int Ed. 2020;59:4294–8.
Imato K, Nakajima H, Yamanaka R, Takeda N. Self-healing polyurethane elastomers based on charge-transfer interactions for biomedical applications. Polym J. 2021;53:355–62.
Liu T, Wang L, Xu J, Fu J. High-performance healable plastics: focusing topological structure design based on constitutional dynamic chemistry. EcoMat. 2023;5:e12412.
Balkenende DWR, Coulibaly S, Balog S, Simon YC, Fiore GL, Weder C. Mechanochemistry with metallosupramolecular polymers. J Am Chem Soc. 2014;136:10493–8.
Imato K, Irie A, Kosuge T, Ohishi T, Nishihara M, Takahara A, et al. Mechanophores with a reversible radical system and freezing-induced mechanochemistry in polymer solutions and gels. Angew Chem Int Ed. 2015;54:6168–72.
Imato K, Kanehara T, Ohishi T, Nishihara M, Yajima H, Ito M, et al. Mechanochromic dynamic covalent elastomers: quantitative stress evaluation and autonomous recovery. ACS Macro Lett. 2015;4:1307–11.
Göstl R, Sijbesma RP. π-extended anthracenes as sensitive probes for mechanical stress. Chem Sci. 2016;7:370–5.
Verstraeten F, Göstl R, Sijbesma RP. Stress-induced colouration and crosslinking of polymeric materials by mechanochemical formation of triphenylimidazolyl radicals. Chem Commun. 2016;52:8608–11.
Imato K, Kanehara T, Nojima S, Ohishi T, Higaki Y, Takahara A, et al. Repeatable mechanochemical activation of dynamic covalent bonds in thermoplastic elastomers. Chem Commun. 2016;52:10482–5.
Oka H, Imato K, Sato T, Ohishi T, Goseki R, Otsuka H. Enhancing mechanochemical activation in the bulk state by designing polymer architectures. ACS Macro Lett. 2016;5:1124–7.
Kosuge T, Imato K, Goseki R, Otsuka H. Polymer–inorganic composites with dynamic covalent mechanochromophore. Macromolecules. 2016;49:5903–11.
Imato K, Natterodt JC, Sapkota J, Goseki R, Weder C, Takahara A, et al. Dynamic covalent diarylbibenzofuranone-modified nanocellulose: mechanochromic behaviour and application in self-healing polymer composites. Polym Chem. 2017;8:2115–22.
Sagara Y, Karman M, Verde-Sesto E, Matsuo K, Kim Y, Tamaoki N, et al. Rotaxanes as mechanochromic fluorescent force transducers in polymers. J Am Chem Soc. 2018;140:1584–7.
Sagara Y, Karman M, Seki A, Pannipara M, Tamaoki N, Weder C. Rotaxane-based mechanophores enable polymers with mechanically switchable white photoluminescence. ACS Central Sci. 2019;5:874–81.
Yildiz D, Baumann C, Mikosch A, Kuehne AJC, Herrmann A, Göstl R. Anti-stokes stress sensing: mechanochemical activation of triplet–triplet annihilation photon upconversion. Angew Chem Int Ed. 2019;58:12919–23.
Imato K, Yamanaka R, Nakajima H, Takeda N. Fluorescent supramolecular mechanophores based on charge-transfer interactions. Chem Commun. 2020;56:7937–40.
Izak-Nau E, Campagna D, Baumann C, Göstl R. Polymer mechanochemistry-enabled pericyclic reactions. Polym Chem. 2020;11:2274–99.
Stratigaki M, Göstl R. Methods for exerting and sensing force in polymer materials using mechanophores. ChemPlusChem. 2020;85:1095–103.
Sagara Y, Traeger H, Li J, Okado Y, Schrettl S, Tamaoki N, et al. Mechanically responsive luminescent polymers based on supramolecular cyclophane mechanophores. J Am Chem Soc. 2021;143:5519–25.
Muramatsu T, Okado Y, Traeger H, Schrettl S, Tamaoki N, Weder C, et al. Rotaxane-based dual function mechanophores exhibiting reversible and irreversible responses. J Am Chem Soc. 2021;143:9884–92.
Kato S, Furukawa S, Aoki D, Goseki R, Oikawa K, Tsuchiya K, et al. Crystallization-induced mechanofluorescence for visualization of polymer crystallization. Nat Commun. 2021;12:126.
Baumann C, Stratigaki M, Centeno SP, Göstl R. Multicolor mechanofluorophores for the quantitative detection of covalent bond scission in polymers. Angew Chem Int Ed. 2021;60:13287–93.
Traeger H, Sagara Y, Kiebala DJ, Schrettl S, Weder C. Folded perylene diimide loops as mechanoresponsive motifs. Angew Chem Int Ed. 2021;60:16191–9.
He S, Stratigaki M, Centeno SP, Dreuw A, Göstl R. Tailoring the properties of optical force probes for polymer mechanochemistry. Chem Eur J. 2021;27:15889–97.
Yamakado T, Saito S. Ratiometric flapping force probe that works in polymer gels. J Am Chem Soc. 2022;144:2804–15.
Kotani R, Yokoyama S, Nobusue S, Yamaguchi S, Osuka A, Yabu H, et al. Bridging pico-to-nanonewtons with a ratiometric force probe for monitoring nanoscale polymer physics before damage. Nat Commun. 2022;13:303.
Thazhathethil S, Muramatsu T, Tamaoki N, Weder C, Sagara Y. Excited state charge-transfer complexes enable fluorescence color changes in a supramolecular cyclophane mechanophore. Angew Chem Int Ed. 2022;61:e202209225.
Xuan M, Schumacher C, Bolm C, Göstl R, Herrmann A. The mechanochemical synthesis and activation of carbon-rich π-conjugated materials. Adv Sci. 2022;9:2105497.
Qiu W, Scofield JMP, Gurr PA, Qiao GG. Mechanochromophore-linked polymeric materials with visible color changes. Macromol Rapid Commun. 2022;43:2100866.
Suga K, Yamakado T, Saito S. Dual ratiometric fluorescence monitoring of mechanical polymer chain stretching and subsequent strain-induced crystallization. J Am Chem Soc. 2023;145:26799–809.
Willis-Fox N, Watchorn-Rokutan E, Rognin E, Daly R. Technology pull: scale-up of polymeric mechanochemical force sensors. Trends Chem. 2023;5:415–31.
Yamamoto T, Takahashi A, Otsuka H. Mechanochromic polymers based on radical-type dynamic covalent chemistry. Bull Chem Soc Jpn. 2023;97:uoad004.
Pan Y, Zhang H, Xu P, Tian Y, Wang C, Xiang S, et al. A mechanochemical reaction cascade for controlling load-strengthening of a mechanochromic. Polym Angew Chem Int Ed. 2020;59:21980–5.
Seshimo K, Sakai H, Watabe T, Aoki D, Sugita H, Mikami K, et al. Segmented polyurethane elastomers with mechanochromic and self-strengthening functions. Angew Chem Int Ed. 2021;60:8406–9.
Kato S, Aoki D, Otsuka H. Toughening of polymer networks by freezing-induced monomer insertion. Chem Lett. 2021;50:1223–5.
Giannantonio MD, Ayer MA, Verde-Sesto E, Lattuada M, Weder C, Fromm KM. Triggered metal ion release and oxidation: ferrocene as a mechanophore in polymers. Angew Chem Int Ed. 2018;57:11445–50.
Hu H, Ma Z, Jia X. Reaction cascades in polymer mechanochemistry. Mater Chem Front. 2020;4:3115–29.
Versaw BA, Zeng T, Hu X, Robb MJ. Harnessing the power of force: development of mechanophores for molecular release. J Am Chem Soc. 2021;143:21461–73.
Sun Y, Neary WJ, Burke ZP, Qian H, Zhu L, Moore JS. Mechanically triggered carbon monoxide release with turn-on aggregation-induced emission. J Am Chem Soc. 2022;144:1125–9.
Shen H, Cao Y, Lv M, Sheng Q, Zhang Z. Polymer mechanochemistry for the release of small cargoes. Chem Commun. 2022;58:4813–24.
Küng R, Göstl R, Schmidt BM. Release of molecular cargo from polymer systems by mechanochemistry. Chem Eur J. 2022;28:e202103860.
Liu W, Qian H. Emerging bio-relevant applications of polymer mechanochemistry. Chin J Chem. 2024;42:2066–70.
Göstl R, Hecht S. Controlling covalent connection and disconnection with light. Angew Chem Int Ed. 2014;53:8784–7.
Kida J, Imato K, Goseki R, Morimoto M, Otsuka H. Photoregulation of retro-diels–alder reaction at the center of polymer chains. Chem Lett. 2017;46:992–4.
Kida J, Imato K, Goseki R, Aoki D, Morimoto M, Otsuka H. The photoregulation of a mechanochemical polymer scission. Nat Commun. 2018;9:3504.
Qian H. The connection between molecular switches and mechanophores. Chem. 2021;7:831–3.
Imato K, Ooyama Y. Polymer mechanochemistry of component parts for artificial molecular machines. Macromol Chem Phys. 2023;224:2300316.
Potisek SL, Davis DA, Sottos NR, White SR, Moore JS. Mechanophore-linked addition polymers. J Am Chem Soc. 2007;129:13808–9.
Davis DA, Hamilton A, Yang J, Cremar LD, Gough D V, Potisek SL, et al. Force-induced activation of covalent bonds in mechanoresponsive polymeric materials. Nature. 2009;459:68–72.
Li M, Zhang Q, Zhou Y-N, Zhu S. Let spiropyran help polymers feel force! Prog Polym Sci. 2018;79:26–39.
Robb MJ, Kim TA, Halmes AJ, White SR, Sottos NR, Moore JS. Regioisomer-specific mechanochromism of naphthopyran in polymeric materials. J Am Chem Soc. 2016;138:12328–31.
McFadden ME, Robb MJ. Force-dependent multicolor mechanochromism from a single mechanophore. J Am Chem Soc. 2019;141:11388–92.
Versaw BA, McFadden ME, Husic CC, Robb MJ. Designing naphthopyran mechanophores with tunable mechanochromic behavior. Chem Sci. 2020;11:4525–30.
McFadden ME, Robb MJ. Generation of an elusive permanent merocyanine via a unique mechanochemical. React Pathw J Am Chem Soc. 2021;143:7925–9.
McFadden ME, Osler SK, Sun Y, Robb MJ. Mechanical force enables an anomalous dual ring-opening reaction of naphthodipyran. J Am Chem Soc. 2022;144:22391–6.
Wang Z, Ma Z, Wang Y, Xu Z, Luo Y, Wei Y, et al. A novel mechanochromic and photochromic polymer film: when rhodamine joins polyurethane. Adv Mater. 2015;27:6469–74.
Wang T, Zhang N, Dai J, Li Z, Bai W, Bai R. Novel reversible mechanochromic elastomer with high sensitivity: bond scission and bending-induced multicolor switching. ACS Appl Mater Interfaces. 2017;9:11874–81.
Wu M, Li Y, Yuan W, Bo GD, Cao Y, Chen Y. Cooperative and geometry-dependent mechanochromic reactivity through aromatic fusion of two. Rhodamines Polym J Am Chem Soc 2022;144:17120–8.
Qian H, Purwanto NS, Ivanoff DG, Halmes AJ, Sottos NR, Moore JS. Fast, reversible mechanochromism of regioisomeric oxazine mechanophores: Developing in situ responsive force probes for polymeric materials. Chem. 2021;7:1080–91.
Qi Q, Sekhon G, Chandradat R, Ofodum NM, Shen T, Scrimgeour J, et al. Force-induced near-infrared chromism of mechanophore-linked. Polym J Am Chem Soc. 2021;143:17337–43.
Surampudi SK, Patel HR, Nagarjuna G, Venkataraman D. Mechano-isomerization of azobenzene. Chem Commun. 2013;49:7519–21.
Lin Y, Hansen HR, Brittain WJ, Craig SL. Strain-dependent kinetics in the cis-to-trans isomerization of azobenzene in bulk elastomers. J Phys Chem B. 2019;123:8492–8.
Li Y, Xue B, Yang J, Jiang J, Liu J, Zhou Y, et al. Azobenzene as a photoswitchable mechanophore. Nat Chem. 2024;16:446–55.
Hu X, McFadden ME, Barber RW, Robb MJ. Mechanochemical regulation of a photochemical reaction. J Am Chem Soc. 2018;140:14073–7.
He S, Schog S, Chen Y, Ji Y, Panitz S, Richtering W, et al. Photoinduced mechanical cloaking of diarylethene-crosslinked microgels. Adv Mater. 2023;35:e2305845.
Fu X, Zhu B, Hu X. Force-triggered atropisomerization of a parallel diarylethene to its antiparallel diastereomers. J Am Chem Soc. 2023;145:15668–73.
He W, Yuan Y, Wu M, Li X, Shen Y, Qu Z, et al. Multicolor chromism from a single chromophore through synergistic coupling of mechanochromic and photochromic subunits. Angew Chem Int Ed. 2023;62:e202218785.
Shimasaki T, Kato S, Shinmyozu T. Synthesis, structural, spectral, and photoswitchable properties of cis- and trans-2,2,2’,2’-Tetramethyl-1,1’-indanylindanes. J Org Chem. 2007;72:6251–4.
Imato K, Sasaki A, Ishii A, Hino T, Kaneda N, Ohira K, et al. Sterically hindered stiff-stilbene photoswitch offers large motions, 90% two-way photoisomerization, and high thermal stability. J Org Chem. 2022;87:15762–70.
Villarón D, Bos JE, Kohl F, Mommer S, Jong Jde, Wezenberg SJ. Photoswitchable Bis(amidopyrroles): modulating anion transport activity independent of binding affinity. J Org Chem. 2023;88:11328–34.
Xu F, Sheng J, Stindt CN, Crespi S, Danowski W, Hilbers MF, et al. All-visible-light-driven stiff-stilbene photoswitches. Chem Sci. 2024;15:6763–9.
Imato K, Ishii A, Kaneda N, Hidaka T, Sasaki A, Imae I, et al. Thermally stable photomechanical molecular hinge: sterically hindered stiff-stilbene photoswitch mechanically isomerizes. JACS Au. 2023;3:2458–66.
May PA, Moore JS. Polymer mechanochemistry: techniques to generate molecular force via elongational flows. Chem Soc Rev. 2013;42:7497–506.
O’Neill RT, Boulatov R. Experimental quantitation of molecular conditions responsible for flow-induced polymer mechanochemistry. Nat Chem. 2023;15:1214–23.
Krishnan BP, Xue L, Xiong X, Cui J. Photoinduced strain-assisted synthesis of a stiff-stilbene polymer by ring-opening metathesis polymerization. Chem Eur J. 2020;26:14828–32.
Hines L, Petersen K, Lum GZ, Sitti M. Soft actuators for small-scale robotics. Adv Mater. 2017;29:1603483.
Ng CSX, Tan MWM, Xu C, Yang Z, Lee PS, Lum GZ. Locomotion of miniature soft robots. Adv Mater. 2021;33:2003558.
Rus D, Tolley MT. Design, fabrication and control of soft robots. Nature. 2015;521:467–75.
Whitesides GM. Soft robotics. Angew Chem Int Ed. 2018;57:4258–73.
Apsite I, Salehi S, Ionov L. Materials for smart soft actuator systems. Chem Rev. 2022;122:1349–415.
Yang L, Zhang Y, Cai W, Tan J, Hansen H, Wang H, et al. Electrochemically-driven actuators: from materials to mechanisms and from performance to applications. Chem Soc Rev. 2024;53:5956–6010.
Gupta B, Goudeau B, Kuhn A. Wireless electrochemical actuation of conducting polymers. Angew Chem Int Ed. 2017;56:14183–6.
Zhang L, Gupta B, Goudeau B, Mano N, Kuhn A. Wireless electromechanical readout of chemical information. J Am Chem Soc. 2018;140:15501–6.
Gupta B, Goudeau B, Garrigue P, Kuhn A. Bipolar conducting polymer crawlers based on triple symmetry breaking. Adv Funct Mater. 2018;28:1705825.
Assavapanumat S, Gupta B, Salinas G, Goudeau B, Wattanakit C, Kuhn A. Chiral platinum–polypyrrole hybrid films as efficient enantioselective actuators. Chem Commun. 2019;55:10956–9.
Gupta B, Afonso MC, Zhang L, Ayela C, Garrigue P, Goudeau B, et al. Wireless coupling of conducting polymer actuators with light emission. ChemPhysChem. 2019;20:941–5.
Arnaboldi S, Gupta B, Benincori T, Bonetti G, Cirilli R, Kuhn A. Absolute chiral recognition with hybrid wireless electrochemical actuators. Anal Chem. 2020;92:10042–7.
Arnaboldi S, Gupta B, Benincori T, Bonetti G, Cirilli R, Kuhn A. Large scale chirality transduction with functional molecular materials. Chem Mater. 2020;32:10663–9.
Arnaboldi S, Salinas G, Bonetti G, Cirilli R, Benincori T, Kuhn A. Bipolar electrochemical measurement of enantiomeric excess with inherently chiral polymer actuators. ACS Meas Au. 2021;1:110–6.
Melvin AA, Gupta B, Tieriekhov K, Nogala W, Garrigue P, Reculusa S, et al. Wireless dual stimuli actuation of dye sensitized conducting polymer hybrids. Adv Funct Mater. 2021;31:2101171.
Gupta B, Zhang L, Melvin AA, Goudeau B, Bouffier L, Kuhn A. Designing tubular conducting polymer actuators for wireless electropumping. Chem Sci. 2021;12:2071–7.
Salinas G, Malacarne F, Bonetti G, Cirilli R, Benincori T, Arnaboldi S, et al. Wireless electromechanical enantio-responsive valves. Chirality. 2023;35:110–7.
Grecchi S, Salinas G, Cirilli R, Benincori T, Ghirardi S, Kuhn A, et al. Miniaturized enantioselective tubular devices for the electromechanical wireless separation of chiral analytes. Chem. 2024;10:660–74.
Fosdick SE, Knust KN, Scida K, Crooks RM. Bipolar electrochemistry. Angew Chem Int Ed. 2013;52:10438–56.
Crooks RM. Principles of bipolar electrochemistry. ChemElectroChem. 2016;3:357–9.
Inagi S. Fabrication of gradient polymer surfaces using bipolar electrochemistry. Polym J. 2016;48:39–44.
Inagi S. Site-selective anisotropic modification of conductive objects by bipolar electropolymerization. Polym J. 2019;51:975–81.
Shida N, Zhou Y, Inagi S. Bipolar electrochemistry: a powerful tool for electrifying functional material synthesis. Acc Chem Res. 2019;52:2598–608.
Shida N, Inagi S. Bipolar electrochemistry in synergy with electrophoresis: electric field-driven electrosynthesis of anisotropic polymeric materials. Chem Commun. 2020;56:14327–36.
Salinas G, Arnaboldi S, Bouffier L, Kuhn A. Recent advances in bipolar electrochemistry with conducting polymers. ChemElectroChem. 2022;9:e202101234.
Imato K, Hino T, Kaneda N, Imae I, Shida N, Inagi S, et al. Wireless electrochemical gel actuators. Small. 2024;20:e2305067.
Geraskina MR, Dutton AS, Juetten MJ, Wood SA, Winter AH. The viologen cation radical pimer: a case of dispersion-driven bonding. Angew Chem Int Ed. 2017;56:9435–9.
Sagara T, Tahara H. Redox of viologen for powering and coloring. Chem Rec. 2021;21:2375–88.
Cai K, Zhang L, Astumian RD, Stoddart JF. Radical-pairing-induced molecular assembly and motion. Nat Rev Chem. 2021;5:447–65.
Nakahata M, Takashima Y, Hashidzume A, Harada A. Redox-generated mechanical motion of a supramolecular polymeric actuator based on host–guest interactions. Angew Chem Int Ed. 2013;52:5731–5.
Takashima Y, Otani K, Kobayashi Y, Aramoto H, Nakahata M, Yamaguchi H, et al. Mechanical properties of supramolecular polymeric materials formed by cyclodextrins as host molecules and cationic alkyl guest molecules on the polymer side chain. Macromolecules. 2018;51:6318–26.
Aramoto H, Osaki M, Konishi S, Ueda C, Kobayashi Y, Takashima Y, et al. Redox-responsive supramolecular polymeric networks having double-threaded inclusion complexes. Chem Sci. 2020;11:4322–31.
Wang B, Tahara H, Sagara T. Driving quick and large amplitude contraction of viologen-incorporated Poly-l-Lysine-based hydrogel by reduction. ACS Appl Mater Interfaces. 2018;10:36415–24.
Porter WW, Vaid TP. Isolation and characterization of phenyl viologen as a radical cation and neutral molecule. J Org Chem. 2005;70:5028–35.
Clarke DE, Olesińska M, Mönch T, Schoenaers B, Stesmans A, Scherman OA. Aryl-viologen pentapeptide self-assembled conductive nanofibers. Chem Commun. 2019;55:7354–7.
Greene AF, Danielson MK, Delawder AO, Liles KP, Li X, Natraj A, et al. Redox-responsive artificial molecular muscles: reversible radical-based self-assembly for actuating hydrogels. Chem Mater. 2017;29:9498–508.
Wang B, Tahara H, Sagara T. Enhancement of deformation of redox-active hydrogel as an actuator by increasing pendant viologens and adding filler or counter-charged polymer. Sens Actuators B. 2021;331:129359.
Delawder AO, Natraj A, Colley ND, Saak T, Greene AF, Barnes JC. Synthesis, self-assembly, and photomechanical actuator performance of a sequence-defined polyviologen crosslinker. Supramol Chem. 2019;31:523–31.
Amir F, Liles KP, Delawder AO, Colley ND, Palmquist MS, Linder HR, et al. Reversible hydrogel photopatterning: spatial and temporal control over gel mechanical properties using visible light photoredox catalysis. ACS Appl Mater Interfaces. 2019;11:24627–38.
Amir F, Li X, Gruschka MC, Colley ND, Li L, Li R, et al. Dynamic, multimodal hydrogel actuators using porphyrin-based visible light photoredox catalysis in a thermoresponsive polymer network. Chem Sci. 2020;11:10910–20.
Ooyama Y, Asada R, Inoue S, Komaguchi K, Imae I, Harima Y. Solvatochromism of novel donor–π–acceptor type pyridinium dyes in halogenated and non-halogenated solvents. N J Chem. 2009;33:2311–6.
Ooyama Y, Kushimoto K, Oda Y, Tokita D, Yamaguchi N, Inoue S, et al. Synthesis and specific solvatochromism of D–π–A type pyridinium dye. Tetrahedron. 2012;68:8577–80.
Ooyama Y, Oda Y, Mizumo T, Ohshita J. Specific solvatochromism of D–π-A type pyridinium dyes bearing various counter anions in halogenated solvents. Tetrahedron. 2013;69:1755–60.
Higashino T, Ooyama Y. Organohalogenochromism (OHC) of Dyes: D-π-A Pyrazinium Dye. Chem Lett. 2021;50:1530–3.
Kozuka K, Imato K, Ooyama Y. Organohalogenochromism (OHC) of D–π–A pyridinium dye polymer films and the colorimetric detection of volatile organic halogen compounds. Mater Adv. 2023;5:2218–29.
Ooyama Y, Egawa H, Yoshida K. A new class of fluorescent dye for sensing water in organic solvents by photo-induced electron transfer – A (Phenylamino)naphtho[1,2-d]oxazol-2-yl-type fluorophore with both proton-binding and proton-donating sites. Eur J Org Chem 2008;2008:5239–43.
Ooyama Y, Egawa H, Yoshida K. The design of a novel fluorescent PET sensor for proton and water: a phenylaminonaphtho[1,2-d]oxazol-2-yl-type fluorophore containing proton donor and acceptor groups. Dyes Pigm. 2009;82:58–64.
Ooyama Y, Sumomogi M, Nagano T, Kushimoto K, Komaguchi K, Imae I, et al. Detection of water in organic solvents by photo-induced electron transfer method. Org Biomol Chem. 2010;9:1314–6.
Ooyama Y, Matsugasako A, Nagano T, Oka K, Kushimoto K, Komaguchi K, et al. Fluorescence PET (photo-induced electron transfer) sensor for water based on anthracene-amino acid. J Photochem Photobiol A. 2011;222:52–55.
Ooyama Y, Matsugasako A, Oka K, Nagano T, Sumomogi M, Komaguchi K, et al. Fluorescence PET (photo-induced electron transfer) sensors for water based on anthracene–boronic acid ester. Chem Commun. 2011;47:4448–50.
Ooyama Y, Matsugasako A, Hagiwara Y, Ohshita J, Harima Y. Highly sensitive fluorescence PET (photo-induced electron transfer) sensor for water based on anthracene–bisboronic acid ester. RSC Adv. 2012;2:7666–8.
Ooyama Y, Uenaka K, Matsugasako A, Harima Y, Ohshita J. Molecular design and synthesis of fluorescence PET (photo-induced electron transfer) sensors for detection of water in organic solvents. RSC Adv. 2013;3:23255–63.
Ooyama Y, Furue K, Uenaka K, Ohshita J. Development of highly-sensitive fluorescence PET (photo-induced electron transfer) sensor for water: anthracene–boronic acid ester. RSC Adv. 2014;4:25330–3.
Ooyama Y, Aoyama S, Furue K, Uenaka K, Ohshita J. Fluorescence sensor for water based on PET (photo-induced electron transfer): Anthracene-bis(aminomethyl)phenylboronic acid ester. Dyes Pigm. 2015;123:248–53.
Ooyama Y, Hato M, Enoki T, Aoyama S, Furue K, Tsunoji N, et al. A BODIPY sensor for water based on a photo-induced electron transfer method with fluorescence enhancement and attenuation systems. N J Chem. 2016;40:7278–81.
Jung HS, Verwilst P, Kim WY, Kim JS. Fluorescent and colorimetric sensors for the detection of humidity or water content. Chem Soc Rev. 2016;45:1242–56.
Ooyama Y, Nomura R, Enoki T, Sagisaka R, Tsunoji N, Ohshita J. Development of a dual-fluorescence emission sensor based on photo-induced electron transfer and aggregation-induced emission enhancement for detection of water. ChemistrySelect. 2017;2:7765–70.
Ooyama Y, Sagisaka R, Enoki T, Tsunoji N, Ohshita J. Tetraphenylethene– and diphenyldibenzofulvene–anthracene-based fluorescence sensors possessing photo-induced electron transfer and aggregation-induced emission enhancement characteristics for detection of water. N J Chem. 2018;42:13339–50.
Tsumura S, Enoki T, Ooyama Y. A colorimetric and fluorescent sensor for water in acetonitrile based on intramolecular charge transfer: D–(π–A)2-type pyridine–boron trifluoride complex. Chem Commun. 2018;54:10144–7.
Enoki T, Ooyama Y. Colorimetric and ratiometric fluorescence sensing of water based on 9-methyl pyrido[3,4- b]indole-boron trifluoride complex. Dalton Trans. 2019;48:2086–92..
Jinbo D, Imato K, Ooyama Y. Fluorescent sensor for water based on photo-induced electron transfer and Förster resonance energy transfer: anthracene-(aminomethyl)phenylboronic acid ester-BODIPY structure. RSC Adv. 2019;9:15335–40.
Imato K, Enoki T, Ooyama Y. Development of an intramolecular charge transfer-type colorimetric and fluorescence sensor for water by fusion with a juloidine structure and complexation with boron trifluoride. RSC Adv. 2019;9:31466–73.
Tsumura S, Ohira K, Imato K, Ooyama Y. Development of optical sensor for water in acetonitrile based on propeller-structured BODIPY-type pyridine–boron trifluoride complex. RSC Adv. 2020;10:33836–43.
Jinbo D, Ohira K, Imato K, Ooyama Y. Development of fluorescent sensors based on a combination of PET (photo-induced electron transfer) and FRET (Förster resonance energy transfer) for detection of water. Mater Adv. 2020;1:354–62.
Mise Y, Imato K, Ogi T, Tsunoji N, Ooyama Y. Fluorescence sensors for detection of water based on tetraphenylethene–anthracene possessing both solvatofluorochromic properties and aggregation-induced emission (AIE) characteristics. N J Chem. 2021;45:4164–73.
Mishra S, Singh AK. Optical sensors for water and humidity and their further applications. Coord Chem Rev. 2021;445:214063.
Nishimoto E, Mise Y, Fumoto T, Miho S, Tsunoji N, Imato K, et al. Tetraphenylethene–anthracene-based fluorescence emission sensor for the detection of water with photo-induced electron transfer and aggregation-induced emission characteristics. N J Chem. 2022;46:12474–81.
Fumoto T, Imato K, Ooyama Y. Elucidation of a detection mechanism of a fluorescent sensor based on photo-induced electron transfer for water. N J Chem. 2022;46:21037–46.
Miho S, Imato K, Ooyama Y. Fluorescent polymer films based on photo-induced electron transfer for visualizing water. RSC Adv. 2022;12:25687–96.
Miho S, Fumoto T, Mise Y, Imato K, Akiyama S, Ishida M, et al. Development of highly sensitive fluorescent sensor and fluorescent sensor-doped polymer films for trace amounts of water based on photo-induced electron transfer. Mater Adv. 2021;2:7662–70.
Fumoto T, Miho S, Mise Y, Imato K, Ooyama Y. Polymer films doped with fluorescent sensor for moisture and water droplet based on photo-induced electron transfer. RSC Adv. 2021;11:17046–50.
Tao K, Imato K, Ooyama Y. Anthracene-(aminomethyl)phenylboronic acid ester-immobilized glass substrates as fluorescent sensing materials based on photo-induced electron transfer for detection and visualization of water. Sens Diagn. 2024;3:631–9.
Li Q, Fuks G, Moulin E, Maaloum M, Rawiso M, Kulic I, et al. Macroscopic contraction of a gel induced by the integrated motion of light-driven molecular motors. Nat Nanotechnol. 2015;10:161–5.
Foy JT, Li Q, Goujon A, Colard-Itté J-R, Fuks G, Moulin E, et al. Dual-light control of nanomachines that integrate motor and modulator subunits. Nat Nanotechnol. 2017;12:540–5.
Chen J, Leung FK-C, Stuart MCA, Kajitani T, Fukushima T, Giessen Evander, et al. Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors. Nat Chem. 2018;10:132–8.
Walden SL, Nguyen PHD, Li H-K, Liu X, Le MTN, Jun LX, et al. Visible light-induced switching of soft matter materials properties based on thioindigo photoswitches. Nat Commun. 2023;14:8298.
Acknowledgements
This work was supported by JSPS KAKENHI (Grant No. 19K15623, 21H01987, and 21H05884), MEXT LEADER (Grant No. A6501), and JST PRESTO (Grant No. JPMJPR21N2).
Funding
Open Access funding provided by Hiroshima University.
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
Conflict of interest
The authors declare no competing interests.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Imato, K., Ooyama, Y. Stimuli-responsive smart polymers based on functional dyes. Polym J (2024). https://doi.org/10.1038/s41428-024-00951-4
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41428-024-00951-4
