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Polymer-Stretching Photoluminescent Regulation by Doping a Single Fluorescent Molecule

2021; Chinese Chemical Society; Volume: 4; Issue: 9 Linguagem: Inglês

10.31635/ccschem.021.202101380

2096-5745

Fan Gu, Yuanhao Li, Tao Jiang, Jianhua Su, Xiang Ma,

Organic Electronics and Photovoltaics

Open AccessCCS ChemistryRESEARCH ARTICLE5 Sep 2022Polymer-Stretching Photoluminescent Regulation by Doping a Single Fluorescent Molecule Fan Gu, Yuanhao Li, Tao Jiang, Jianhua Su and Xiang Ma Fan Gu Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 , Yuanhao Li Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 , Tao Jiang Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 , Jianhua Su Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 and Xiang Ma *Corresponding author: E-mail Address: [email protected] Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 https://doi.org/10.31635/ccschem.021.202101380 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Photoluminescent materials play an essential part in the application of polymer systems. However, intrinsic polymer systems have rarely been intuitively interpreted based on photoluminescent regulation. A novel photoluminescent mechanism called vibration-induced emission (VIE) has recently garnered considerable attention due to its multicolor fluorescence from a single molecular entity. Based on the unique fluorescent properties of VIE molecules, we have doped 9,14-diphenyl-9,14-dihydrodibenzo[a,c]-phenazine (DPAC) and its derivative DPAC-11-carbonitrile in two stretchable polymers, poly(ε-caprolactone) and ethylene vinyl acetate (EVA) copolymer, to explore the important relationship between luminophores and polymer systems. This research focuses on the multicolor photoluminescence of the blend films that result from stretching exertions and temperature responses. The successive conformational alterations of VIE molecules endow continuous photoluminescent changes. Meanwhile, the multicolor variations also provide specific visual evidence regarding the amplified tensile stresses and microstructural changes in the polymer. This demonstration therefore provides advantageous insight into the development of functional optical materials. Download figure Download PowerPoint Introduction Recently, photoluminescent mechanisms with luminescent-tunable behaviors and stable emission properties have ushered in rapid development in both academic exploration1,2 and fundamental inventions.3–6 Based on this, the development of many potential applications, such as detection,7 data storage,8 anti-counterfeiting,9,10 and displays,11–14 has created great value based on the dramatic illumination of functional optical materials. However, the optical function achieved by photoluminescent luminophores is not always established by the luminophores themselves.15,16 Owing to the unique properties of these materials, most researchers have developed innovative photoluminescent materials that rely on the combination of luminophores and polymers by doping and polymerization.17–21 Thus, the application of specific polymers has become prominent in the area of photoluminescent materials.22–24 Luminophores have undoubtedly inspired many possibilities for the use of polymer systems. Nonetheless, the photoluminescent mechanism has rarely been utilized in the detection and analysis of polymer systems. There are still challenges in intrinsic amplification of polymers due to the advantages of photoluminescent regulation. Due to the limitations of luminophores, many luminescent systems exhibit single-color emission or multicolor emissions under certain conditions.25,26 This induces restrictions on the further development of functional optical materials in polymer systems. Therefore, it is of great importance to realize internal visualization in polymer systems by fully utilizing the representative behavior of photoluminescent regulation. Vibration-induced emission (VIE),27–29 as an emerging photoluminescent mechanism, has drawn great attention in recent years, owing to its tunable multicolor emission between different successive configurations. This mechanism has been attributed to the saddle-like VIE molecules of 9,14-diphenyl-9,14-dihydrodibenzo[a,c]-phenazine (DPAC) and its derivatives with consecutive conformations from bent to planar,30–33 resulting in appealing multicolor emission (blue and orange red) from a single molecular entity. Under different external environmental conditions, such as solvent polarity,34,35 viscosity,36,37 and temperature,38 VIE molecules display excellent photoluminescent properties with favorable reversibility and contollability.39,40 Based on this phenomenon, we propose a distinct strategy involving the exertion of an external stretching force to explore and report the very special and interesting photoluminescent characteristics of VIE molecules in poly(ε-caprolactone) and ethylene vinyl acetate (EVA) polymer systems. As biodegradable polymers, poly(ε-caprolactone) and EVA materials with good extensibility properties have been generally accepted to form homogeneous mixtures with other compounds in the melt and solution. The physical parameters of poly(ε-caprolactone) and EVA have been extensively explored in many previous studies.41–44 However, the measurement of intrinsic alterations in polymer systems still requires sophisticated instrumental detection, which has not been represented by an intuitive method so far. Therefore, we attempted to visualize and amplify the microcosmos of poly(ε-caprolactone) and EVA by utilizing the multicolor luminescent properties of VIE molecules. The exploration of VIE theory would contribute to gaining a profound understanding of polymer systems, as well as applications for further development of functional optical materials. In this work, we synthesized two VIE molecules, DPAC and DPAC-11-carbonitrile (DPAC-CN). These two VIE molecules were simply doped into two polymer systems respectively to explore the intriguing photoluminescent mechanisms. Polymer systems, including poly(ε-caprolactone) and EVA, were chosen because of their excellent stretchability and flexibility. This was the reason that the VIE molecules exhibited different conformations from bent to planar and represented dramatic photoluminescent behaviors in these polymers. According to the gradual conformation changes, the novel blend films we obtained performed not only diverse fluorescent emissions but also precise recording of exerted tensile stress and visualized changes in the microstructure and crystallinity of polymer systems. Additionally, the temperature responses in both polymer systems were also explored. The material obtained from VIE molecules was further utilized as a temperature detector for the recognition of body temperature. Therefore, the two systems with VIE molecules made significant contributions to the amplification of the microcosmos in polymers through consecutive photoluminescent emissions. Experimental Methods The 1H NMR, 13C NMR, and electron ionization mass spectra have proven the successful synthesis of compound DPAC and DPAC-CN. The VIE molecules of DPAC and DPAC-CN possessed multicolor emissions, owing to the consecutive conformations that varied with different surroundings (detailed synthetic processes are reported in Supporting Information Scheme S1 and Figures S1–S6). As shown in Supporting Information Figure S7, DPAC and DPAC-CN emitted blue fluorescence in the solid state with respective fluorescent quantum yields (QYs) of 5.9% and 3.8%. The relevant red fluorescent emission in toluene solution is shown in Supporting Information Figure S8. The related mechanism has been fully studied in our previous reports.30–38 The blend films were obtained by doping DPAC and DPAC-CN in poly(ε-caprolactone) or EVA (Figure 1). The detailed preparation processes are provided in the Supporting Information. UV–vis, fluorescent spectra, stress–strain curves, X-ray diffraction (XRD) spectra, differential scanning calorimetry (DSC) thermograms, photographs, scanning electron microscopy (SEM), and tensile stress recording are also available in the Supporting Information. For further exploration, this research focused on microcosmic disclosure in polymer systems by photoluminescent regulation of VIE molecules (Figure 1). Figure 1 | Illustration of the film preparation and the chemical structures of DPAC and DPAC-CN in different conformations, from bent to planar, upon stretching and heating in the excited states. Download figure Download PowerPoint Results and Discussion Microcosmic disclosure in a doping system of poly(ε-caprolactone) by VIE photoluminescent regulation To eliminate the influence of poly(ε-caprolactone) on luminescent behavior, fluorescent spectra and absorption spectra of the poly(ε-caprolactone) film were obtained under the same test conditions as P(DPAC) and P(DPAC-CN), as shown in Supporting Information Figures S9 and S10. It was demonstrated that the poly(ε-caprolactone) film had no effect on the photoluminescence in either the original state or the stretched state. Based on this, we prepared films at different doping ratios with increasing VIE molecule concentrations (wt %), namely, P(DPAC-0.1%), P(DPAC-0.3%), P(DPAC-0.5%), P(DPAC-1.5%), P(DPAC-2.5%), P(DPAC-5%), P(DPAC-CN-0.1%), P(DPAC-CN-0.3%), P(DPAC-CN-0.5%), P(DPAC-CN-1.5%), P(DPAC-CN-2.5%), and P(DPAC-CN-5%). The fabricated films exhibited different photoluminescent behaviors with increasing VIE molecule concentrations in poly(ε-caprolactone). Taking P(DPAC) as an example, the resulting normalized fluorescent spectra represented multicolor fluorescence from light pink to yellow green, as shown in Figures 2a and 2c. The short wavelength emissions at different ratios red-shifted increasingly from 425 to 470 nm. However, the long wavelength emissions were all located at 600 nm and did not change significantly. The addition of DPAC led to conjugations resulting from intermolecular stacking, which did not increase the conjugations of the planar configuration in the excited states. Furthermore, the long wavelength intensity between P(DPAC-0.1%) and P(DPAC-0.5%) rose slightly according to the normalized fluorescent spectra, meaning that the DPAC molecules were dispersive with little restriction at low concentrations. Conversely, the long wavelength intensity declined with further increases in DPAC% from P(DPAC-0.5%) to P(DPAC-5%), owing to the limitations caused by intermolecular stacking in the excited state. The absorption spectra of P(DPAC) and P(DPAC-CN) films are shown in Supporting Information Figure S11 to illustrate this behavior. The redshifts of the absorption peaks provide strong evidence for increases in intermolecular stacking and conjugation. Similar multicolor variations also existed in P(DPAC-CN), as shown in Figures 2b and 2c. With the electron withdrawing effect of –C≡N, P(DPAC-CN) exhibited more red-shift short wavelength emissions from 465 to 495 nm. Owing to the effect of intermolecular stacking, the fluorescent QYs of the P(DPAC) and P(DPAC-CN) films, as measured and shown in Figure 2d, did not change significantly with additional doping concentrations but exhibited stronger photoluminescent properties than the original VIE molecules. Figure 2 | Normalized fluorescent spectra of (a) P(DPAC) and (b) P(DPAC-CN) films with different doping ratios. (c) Representative photographs of P(DPAC) and P(DPAC-CN) films with different doping ratios under 365 nm excitation. (d) Fluorescence QYs of P(DPAC) and P(DPAC-CN) films with different doping ratios (λex = 365 nm). Download figure Download PowerPoint Inspired by the various photoluminescent properties in P(DPAC) and P(DPAC-CN) films, we further studied the tension-visualization behaviors in these blend films with certain external tensile stresses. Due to the commendable extensibility of poly(ε-caprolactone), the blend films with VIE molecules were stretched at a constant speed (10 mm min−1) while recording the precise corresponding tensile stresses. As shown in Figure 3, stretching experiments were conducted on P(DPAC-0.1%), P(DPAC-0.5%), P(DPAC-5%), P(DPAC-CN-0.1%), P(DPAC-CN-0.5%), and P(DPAC-CN-5%) to record the consecutive photoluminescent changes in this system. The stress–strain curves of the films in Supporting Information Figure S12 were markedly parallel and agreed with the poly(ε-caprolactone) curve in both elongation and breaking strength. The corresponding average mechanical strength was 28 MPa, and the satisfactory stretchability was 900%, implying that the small amount of VIE molecules did not induce interference in the nature of poly(ε-caprolactone). Moreover, the XRD spectra and DSC thermograms also demonstrated this point, owing to the small changes among poly(ε-caprolactone), P(DPAC-0.5%) and P(DPAC-0.5%) in the stretched state, as exhibited in Supporting Information Figures S13 and S14. Figure 3 | Normalized fluorescent spectra of (a) P(DPAC-0.1%), (b) P(DPAC-0.5%), (c) P(DPAC-5%), (d) P(DPAC-CN-0.1%), (e) P(DPAC-CN-0.5%), and (f) P(DPAC-CN-5%) (λex = 365 nm). The line color exhibited is connected to the luminescent color of the blend films. The emissions in the middle of stretched films were recorded. (g) Photoluminescent images of P(DPAC-0.5%) at different stretching states under 365 nm excitation. SEM images of the P(DPAC-0.5%) film before and after stretching, with scale bars of (h) 300 μm and (i) 50 μm. Download figure Download PowerPoint Specifically, blend films doped with VIE molecules emitted distinct fluorescence during the stretching process upon 365 nm excitation, as compared to the original and stretched films without 365 nm excitation shown in Supporting Information Figure S15. This variation in fluorescent color significantly matched with the continuous stretching process. As shown in Figures 3a–3c, the blend films of P(DPAC-0.1%), P(DPAC-0.5%), and P(DPAC-5%), as prepared in rectangular shapes (20 × 10 mm), were stretched separately at a uniform speed. Then, the normalized fluorescent spectra of the stretched parts were recorded at elongations from 0% to 900%. The original states of these films showed two characteristic emission peaks (425 and 600 nm) that were properly assigned to the luminophore DPAC. The intensity of the broad emission peak located at 425 nm gradually decreased, and the peak was finally replaced by the 480 nm emission peak, as shown in Figure 3c. This phenomenon related to the stretching process convincingly demonstrated that stretching of the films induced narrow intermolecular distances of VIE molecules. Furthermore, the intensity of the long wavelength emission decreased gradually with slow elongation, meaningfully reinforcing the successive configuration limitations of VIE molecules in the excited state. The restriction that weakened the red fluorescent emission of blend films finally eliminated all but the blue emission, implying stronger restrictions of molecular configuration induced by stretching. This was demonstrated by the stretching images of P(DPAC-0.5%) shown in Figure 3g. The progressive increases in the fluorescent QYs with deformations at 100%, 400%, and 900%, as shown in Supporting Information Figure S16, might also account for the facilitation of narrow intermolecular distances. Similarly, P(DPAC-CN) exhibited fluorescent color conversions from light orange to green after stretching (Figures 3d–3f and Supporting Information Figure S15 and Video S1). Increases also occurred in the QYs of P(DPAC-CN-0.5%). This dramatic fluorescent behavior in blend films was also captured again once the stretched films were redissolved in dichloromethane (DCM) and dried off, demonstrating the excellent reversibility of fluorescent polymer materials ( Supporting Information Figure S17). To evaluate the restricted effect of poly(ε-caprolactone), we performed absorption measurements of P(DPAC-0.5%) and P(DPAC-CN-0.5%) upon stretching, as shown in Supporting Information Figure S18. The existence of blue-shift absorption peaks in the original and stretched states implied a decrease in the luminophore concentration, indicating further narrow distances of VIE molecules in polymer networks. The limitations induced by stretching mainly functioned on the configurations of the excited state of VIE molecules and completely decreased the long wavelength intensity. This decrease confirmed that the changes in the surroundings of the obtained films, as observed between the original states and the stretched states, played a crucial role in the fluorescent emission of VIE molecules. The SEM images of P(DPAC-0.5%) (Figures 3h and 3i) provided strong evidence to support the idea that more restrictions were induced by stretching. With further elongations at 300% and 900%, the surfaces of the films showed obvious changes in the microstructure and crystallinity of poly(ε-caprolactone). This phenomenon has been identified in previous research.41,42 However, owing to the different conformations realized by the VIE molecules, the changes in microstructure and crystallinity were visualized based on their multicolor photoluminescent behaviors under 365 nm irritation. This enabled a profound understanding of amplifying microscopic changes in polymers through photochemistry. Additionally, the films obtained with dramatic fluorescent behaviors not only demonstrated the microstructure and crystallinity changes in poly(ε-caprolactone) but also recorded the continuous force value through their diverse fluorescent emissions. Owing to the differences in the photoluminescent properties between DPAC and DPAC-CN, the resulting fluorescent color conversions differed in Commission Internationale de L'Eclairage (CIE) chromaticity coordinate value, as shown in Supporting Information Figures S19 and S20. In addition, every force value was matched with every CIE coordinate value for the exact elongation ratios, as shown in Supporting Information Tables S1 and S2. The VIE theory enabled consecutive configuration changes, which supported successive multicolor fluorescence upon increasing elongation. This could be a significant symbol for use in the realization of intercalibration between photoluminescent and mechanical properties. Furthermore, the blend films we obtained demonstrated sensitive temperature responses from 25 to 50 °C. The normalized fluorescent spectra of P(DPAC-0.5%) and P(DPAC-CN-0.5%) at different temperatures were used as examples, as shown in Figures 4a and 4b. With increasing temperatures, the long wavelength intensities increased dramatically, and the fluorescent colors of films changed from light pink (light orange for P(DPAC-CN-0.5%)) to orange red. The multicolor changes are recorded in Supporting Information Video S2. The higher temperature activated the intramolecular motions of VIE molecules and generated more planar conformations in the excited state.36 The temperature responses of the blend films were also matched to every CIE coordinate value with increasing temperature, as shown in Supporting Information Figure S21 and Table S3. Owing to the increases in intramolecular motions, the QYs of the fluorescent emissions decreased gradually. Upon heating and cooling for eight cycles, this process exhibited favorable reversibility without substantial changes in the fluorescent behavior, as shown in Supporting Information Figure S22. Compared with the limitations induced by the stretching process, the increasing temperature provided more flexible space for the VIE molecules. Compared with stretching, more red fluorescent emissions also demonstrated the more flexible surroundings in the polymer system upon temperature increase. Figure 4 | Normalized fluorescent spectra of (a) P(DPAC-0.5%) and (b) P(DPAC-CN-0.5%) with increasing temperatures from 25 to 50 °C (λex = 365 nm). Download figure Download PowerPoint Microcosmic disclosure in a doping system of EVA by VIE photoluminescent regulation In addition to the controllable tension visualization of VIE molecules in the poly(ε-caprolactone) system, similar properties were also achieved in the EVA system. As an advanced copolymer, EVA has been widely used in industrial applications, such as flexible packaging, membranes, photovoltaic cells, and adhesives.43,44 Owing to its similar tensile properties and satisfactory elasticity, EVA was also chosen as a polymer matrix for VIE molecules. The EVA materials were colorless transparent films, as shown in Supporting Information Figure S23. To eliminate natural interference from EVA, stress–strain tests were conducted and XRD spectra were obtained for EVA-(DPAC), EVA-(DPAC-CN), and EVA. Such characterizations indicated little alteration of the materials with VIE molecules, as shown in Supporting Information Figures S24 and S25. The absorption spectra and fluorescent spectra of EVA itself also confirmed this conclusion ( Supporting Information Figures S10 and S26). Nonetheless, EVA possessed not only a satisfactory stretchability of 600% but also a favorable elasticity ( Supporting Information Figure S27), enabling the recovery of photoluminescent changes. As shown in Figure 5a and Supporting Information Figure S28, EVA-(DPAC) and EVA-(DPAC-CN) presented similar multicolor fluorescent behaviors from light pink to pale blue (light orange to light green for EVA-(DPAC-CN)) with elongation changes from 0% to 600%. The intensity of the long wavelength peak gradually decreased, owing to the limitations of molecular conformation that resulted from stretching. Moreover, the long wavelength peak increased again once the tensile stress was gradually relaxed, demonstrating the release of the restriction of VIE molecules in the excited state. The fluorescent color also returned to the original state, as shown in Supporting Information Video S3. The absorption spectra in Supporting Information Figure S29 also verified the recovery of DPAC and DPAC-CN. SEM images of EVA-(DPAC) were obtained with scale bars of 40 and 4 μm, as shown in Supporting Information Figure S30. Compared to the stretched state, the surfaces in the relaxed state appeared slightly curved without external force exertion. However, both the stretched state and the relaxed state showed meaningful changes in microstructure and crystallinity, contributing to the photoluminescent performance of the VIE molecules. Figure 5 | (a) Representative photographs and normalized fluorescent spectra of EVA-(DPAC) in different stretching states and relaxation states (λex = 365 nm). The line color represents the luminescent color of the related blend films. The emissions in the middle of stretched films were recorded. (b) Normalized fluorescent spectra of EVA-(DPAC) with increasing temperatures from 5 to 50 °C (λex = 365 nm). Inset: representative photographs under 365 nm excitation. (c) Fluorescence emission intensities at 600 nm upon heating and cooling an EVA-(DPAC) film from 5 to 50 °C for eight cycles. (d) Schematic illustration of the temperature response and photographs of the EVA-(DPAC) film at 10 °C, as generated by palm pressing under 365 nm excitation. Download figure Download PowerPoint Additionally, the blend films of EVA with VIE molecules exhibited a precise thermal response with temperature changes from 5 to 50 °C. The films of EVA were more sensitive than poly(ε-caprolactone). As shown in Figure 5b and Supporting Information Figure S31, owing to the facilitation of the intramolecular motions of DPAC and DPAC-CN, the normalized fluorescent curves represented multicolor fluorescence from light blue to orange red (pale green to orange red for EVA-(DPAC-CN)). The corresponding CIE coordinate values, as matched with the exact temperatures, are shown in Supporting Information Figure S32 and Table S4. The blend films of EVA exhibited rapid nonlinear responses of approximately 125 s upon constant increasing temperature ( Supporting Information Figure S33). And the films recovered to their original fluorescent colors faster than poly(ε-caprolactone) from 50 °C to room temperature, as shown in Supporting Information Video S4. The films exhibited excellent reversibility upon heating and cooling for eight cycles (Figure 5c). Furthermore, this significant thermal response in EVA even occurred in response to body temperature exposure by palm pressing. As shown in Figure 5d, EVA-(DPAC) was processed into a large piece of blend film. The original fluorescent color was recorded at 10 °C under UV light excitation. However, the fluorescent color of the pressed palm-shaped area turned orange upon 365 nm irradiation. Once the pressing stopped, the fluorescent color recovered quickly without any traces of its previous pressed color. This phenomenon implied that the blend films of EVA with VIE molecules could be utilized as sensitive detectors of human body temperature. Conclusions We synthesized two VIE molecules, DPAC and DPAC-CN, with very special VIE properties. And these VIE molecules were simply doped in poly(ε-caprolactone) and EVA systems to obtain functional optical materials. We systematically explored the photoluminescent properties of the two obtained polymer systems, paving the way for disclosing macrocosmic changes in polymer systems based on the continuous configurations of the VIE molecules. This research has not only reported continuous photoluminescent changes but also established relationships between different forces, temperatures, and photoluminescent behavior. The nature of poly(ε-caprolactone) and the EVA system has been intuitively amplified, based on their photoluminescent properties. The visualization of polymer microcosmos can greatly affect the development of polymer materials. Furthermore, this study has provided an outstanding strategy for elucidating new understanding of polymer systems in the near future. Supporting Information Supporting Information is available and includes general procedures, characterization of products, and other spectroscopic data. Conflict of Interest X.M., F.G., and H.T. are inventors on a provisional patent application related to this work that has been filed by the East China University of Science and Technology (Application no. 202110327580.5, date: 26 Mar. 2021). The authors declare no other competing interests. Funding Information We gratefully acknowledge financial support from the National Natural Science Foundation of China (NSFC nos. 21788102, 22125803, 22020102006, and 21871083), a project supported by Shanghai Municipal Science and Technology Major Project (grant no. 2018SHZDZX03), the Program of Shanghai Academic/Technology Research Leader (no. 20XD1421300), the "Shu Guang" project supported by the Shanghai Municipal Education Commission and the Shanghai Education Development Foundation (no. 19SG26), the Innovation Program of the Shanghai Municipal Education Commission (no. 2017-01-07-00-02-E00010), and the Fundamental Research Funds for the Central Universities. Preprint Acknowledgment Research presented in this article was posted on a preprint server prior to publication in CCS Chemistry. The corresponding preprint article can be found here: https://doi.org/10.26434/chemrxiv.14464710.v1 Acknowledgments The authors thank Dr. T. Jiang for his helpful discussions. References 1. Chen C.; Chi Z.; Chong K. C.; Batsanov A. S.; Yang Z.; Mao Z.; Yang Z.; Liu B.Carbazole Isomers Induce Ultralong Organic Phosphorescence.Nat. Mater.2021, 20, 175–180. Google Scholar 2. Kabe R.; Adachi C.Organic Long Persistent Luminescence.Nature2017, 550, 384–387. Google Scholar 3. Khasminskaya S.; Pyatkov F.; Słowik K.; Ferrari S.; Kahl O.; Kovalyuk V.; Rath P.; Vetter A.; Hennrich F.; Kappes M. M.; Gol'tsman G.; Korneev A.; Rockstuhl C.; Krupke R.; Pernice W. H.Fully Integrated Quantum Photonic Circuit with an Electrically Driven Light Source.Nat. Photon.2016, 10, 727–732. Google Scholar 4. Uoyama H.; Goushi K.; Shizu K.; Nomura H.; Adachi C.Highly Efficient Organic Light-Emitting Diodes from Delayed Fluorescence.Nature2012, 492, 234–238. Google Scholar 5. Li Q.; Li Z.Molecular Packing: Another Key Point for the Performance of Organic and Polymeric Optoelectronic Materials.Acc. Chem. Res.2020, 53, 962–973. Google Scholar 6. Liu F.; Liao Q.; Wang J.; Gong Y.; Dang Q.; Ling W.; Han M.; Li Q.; Li Z.Intermolecular Electronic Coupling of 9-Methyl-9H-Dibenzo[a,c] Carbazole for Strong Emission in Aggregated State by Substituent Effect.Sci. China Chem.2020, 63, 1435–1442. Google Scholar 7. Zhang F.; Shen Q.; Shi X.; Li S.; Wang W.; Luo Z.; He G.; Zhang P.; Tao P.; Song C.; Zhang W.; Zhang D.; Deng T.; Shang W.Infrared Detection Based on Localized Modification of Morpho Butterfly Wings.Adv. Mater.2015, 27, 1077–1082. Google Scholar 8. Liu C.; Fan Z.; Tan Y.; Fan F.; Xu F.Tunable Structural Color Patterns Based on the Visible-Light-Responsive Dynamic Diselenide Metathesis.Adv. Mater.2020, 32, 1907569. Google Scholar 9. Qi Y.; Chu L.; Niu W.; Tang B.; Wu S.; Ma W.; Zhang S.New Encryption Strategy of Photonic Crystals with Bilayer Inverse Heterostructure Guided from Transparency Response.Adv. Funct. Mater.2019, 29, 1903743. Google Scholar 10. Lee H. S.; Shim T. S.; Hwang H.; Yang S.; Kim S. H.Colloidal Photonic Crystals toward Structural Color Palettes for Security Materials.Chem. Mater.2013, 25, 2684. Google Scholar 11. Chi Z.; Zhang X.; Xu B.; Zhou X.; Ma C.; Zhang Y.; Liu S.; Xu J.Recent Advances in Organic Mechanofluorochromic Materials.Chem. Soc. Rev.2012, 41, 3878–3896. Google Scholar 12. Xue P.; Ding J.; Wang P.; Lu R.Recent Progress in the Mechanochromism of Phosphorescent Organic Molecules and Metal Complexes.J. Mater. Chem. C2016, 4, 6688–6706. Google Scholar 13. Fan W.; Zeng J.; Gan Q.; Ji D.; Song H.; Liu W.; Shi L.; Wu L.Iridescence-Controlled and Flexibly Tunable Retroreflective Structural Color Film for Smart Displays.Sci. Adv.2019, 5, eaaw8755. Google Scholar 14. Chen J.; Ye F.; Lin Y.; Chen Z.; Liu S.; Yin J.Vinyl-Functionalized Multicolor Benzothiadiazoles: Design, Synthesis, Crystal Structures and Mechanically-Responsive Performance.Sci. China Chem.2019, 62, 440–450. Google Scholar 15. Li M.; Berritt S.; Wang C.; Yang X.; Liu Y.; Sha S.; Wang B.; Wang R.; Gao X.; Li Z.; Fan X.; Tao Y.; Walsh P. J.Sulfenate Anions as Organocatalysts for Benzylic Chloromethyl Coupling Polymerization via C=C Bond Formation.Nat. Commun.2018, 9, 1754. Google Scholar 16. Lien D.-H.; Uddin S. Z.; Yeh M.; Amani M.; Kim H.; Ager J. W.; Yablonovitch E.; Javey A.Electrical Suppression of All Nonradiative Recombination Pathways in Monolayer Semiconductors.Science2019, 364, 468–471. Google Scholar 17. Ji S.; Fan F.; Sun C.; Yu Y.; Xu H.Visible Light-Induced Plasticity of Shape Memory Polymers.ACS Appl. Mater. Interfaces2017, 9, 33169–33175. Google Scholar 18. Zhang Q.; Deng Y.; Shi C.; Feringa B. L.; Tian H.; Qu D.Dual Closed-Loop Chemical Recycling of Synthetic Polymers by Intrinsically Reconfigurable Poly(disulfides).Matter2021, 4, 1352–1364. Google Scholar 19. Xiao T.; Zhong W.; Zhou L.; Xu L.; Sun X.; Elmes R. B.; Hu X.; Wang L.Artificial Light-Harvesting Systems Fabricated by Supramolecular Host–Guest Interactions.Chin. Chem. Lett.2019, 30, 31–36. Google Scholar 20. Sun X.; Liu D.; Tian D.; Zhang X.; Wu W.; Wan W.The Introduction of the Barbier Reaction into Polymer Chemistry.Nat. Commun.2017, 8, 1210. Google Scholar 21. Bolton O.; Lee K.; Kim H. J.; Lin K. Y.; Kim J.Activating Efficient Phosphorescence from Purely Organic Materials by Crystal Design.Nat. Chem.2011, 3, 205–210. Google Scholar 22. Shi C.; Zhang Q.; Yu C.; Rao S.; Yang S.; Tian H.; Qu D.An Ultrastrong and Highly Stretchable Polyurethane Elastomer Enabled by a Zipper-Like Ring-Sliding Effect.Adv. Mater.2020, 32, 2000345. Google Scholar 23. Zhang Q.; Shi C.; Qu D.; Long Y.; Feringa B. L.; Tian H.Exploring a Naturally Tailored Small Molecule for Stretchable, Self-Healing, and Adhesive Supramolecular Polymers.Sci. Adv.2018, 4, eaat8192. Google Scholar 24. Liu J.; Wang N.; Yu Y.; Yan Y.; Zhang H.; Li J.; Yu J.Carbon Dots in Zeolites: A New Class of Thermally Activated Delayed Fluorescence Materials with Ultralong Lifetimes.Sci. Adv.2017, 3, e1603171. Google Scholar 25. Sagara Y.; Yamane S.; Mitani M.; Weder C.; Kato T.Mechanoresponsive Luminescent Molecular Assemblies: An Emerging Class of Materials.Adv. Mater.2016, 28, 1073–1095. Google Scholar 26. Sagara Y.; Karman M.; Verde-Sesto E.; Matsuo K.; Kim Y.; Tamaoki N.; Weder C.Rotaxanes as Mechanochromic Fluorescent Force Transducers in Polymers.J. Am. Chem. Soc.2018, 140, 1584–1587. Google Scholar 27. Zhang Z.; Wu Y.; Tang K.; Chen C.; Ho J.; Su J.; Tian H.; Chou P.Excited-State Conformational/Electronic Responses of Saddle-Shaped N,N′-Disubstituted-Dihydrodibenzo[a,c]phenazines: Wide-Tuning Emission from Red to Deep Blue and White Light Combination.J. Am. Chem. Soc.2015, 137, 8509–8520. Google Scholar 28. Chen W.; Chen C.; Zhang Z.; Chen Y.; Chao W.; Su J.; Tian H.; Chou P.Snapshotting the Excited-State Planarization of Chemically Locked N,N′-Disubstituted Dihydrodibenzo[a,c]phenazines.J. Am. Chem. Soc.2017, 139, 1636–1644. Google Scholar 29. Wang H.; Zhang Z.; Zhou H.; Wang T.; Su J.; Tong X.; Tian H.Cu-Catalyzed C-H Amination/Ullmann N-Arylation Domino Reaction: A Straightforward Synthesis of 9,14-Diaryl-9,14-Dihydrodibenzo[a,c]phenazine.Chem. Commun.2016, 52, 5459–5462. Google Scholar 30. Zhang Z.; Chen C.; Chen Y.; Wei Y.; Su J.; Tian H.; Chou P.Tuning the Conformation and Color of Conjugated Polyheterocyclic Skeletons by Installing Ortho-Methyl Groups.Angew. Chem., Int. Ed.2018, 57, 9880–9884. Google Scholar 31. Zhang Z.; Song W.; Su J.; Tian H.Vibration-Induced Emission (VIE) of N,N′-Disubstituted-Dihydribenzo[a,c]phenazines: Fundamental Understanding and Emerging Applications.Adv. Funct. Mater.2020, 30, 1902803. Google Scholar 32. Zhou H.; Mei J.; Chen Y.; Chen C.; Chen W.; Zhang Z.; Su J.; Chou P.; Tian H.Phenazine-Based Ratiometric Hg2+ Probes with Well-Resolved Dual Emissions: A New Sensing Mechanism by Vibration-Induced Emission (VIE).Small2016, 12, 6542–6546. Google Scholar 33. Shi L.; Song W.; Lian C.; Chen W.; Mei J.; Su J.; Liu H.; Tian H.Dual-Emitting Dihydrophenazines for Highly Sensitive and Ratiometric Thermometry over a Wide Temperature Range.Adv. Opt. Mater.2018, 6, 1800190. Google Scholar 34. Huang W.; Sun L.; Zheng Z.; Su J.; Tian H.Colour-Tunable Fluorescence of Single Molecules Based on the Vibration Induced Emission of Phenazine.Chem. Commun.2015, 51, 4462–4464. Google Scholar 35. Wang H.; Li Y.; Zhang Y.; Mei J.; Su J.A New Strategy for Achieving Single-Molecular White-Light Emission: Using Vibration-Induced Emission (VIE) plus Aggregation-Induced Emission (AIE) Mechanisms as a Two-Pronged Approach.Chem. Commun.2019, 55, 1879–1882. Google Scholar 36. Wang J.; Yao X.; Liu Y.; Zhou H.; Chen W.; Sun G.; Su J.; Ma X.; Tian H.Tunable Photoluminescence Including White-Light Emission Based on Noncovalent Interaction-Locked N,N′-Disubstituted Dihydrodibenzo[a,c]phenazines.Adv. Opt. Mater.2018, 6, 1800074. Google Scholar 37. Sun G.; Pan J.; Wu Y.; Liu Y.; Chen W.; Zhang Z.; Su J.Supramolecular Assembly-Driven Color-Tuning and White-Light Emission Based on Crown-Ether-Functionalized Dihydrophenazine.ACS Appl. Mater. Interfaces2020, 12, 10875–10882. Google Scholar 38. Sun G.; Zhou H.; Liu Y.; Li Y.; Zhang Z.; Mei J.; Su J.Ratiometric Indicator Based on Vibration-Induced Emission for in Situ and Real-Time Monitoring of Gelation Processes.ACS Appl. Mater. Interfaces2018, 10, 20205–20212. Google Scholar 39. Zhang Z.; Sun G.; Chen W.; Su J.; Tian H.The Endeavor of Vibration-Induced Emission (VIE) for Dynamic Emissions.Chem. Sci.2020, 11, 7525–7537. Google Scholar 40. Huang Z.; Jiang T.; Wang J.; Ma X.; Tian H.Real-Time Visual Monitoring of Kinetically Controlled Self-Assembly.Angew. Chem. Int. Ed.2020, 60, 2855–2860. Google Scholar 41. Jiang Z.; Wang Y.; Fu L.; Whiteside B.; Wyborn J.; Norris K.; Wu Z.; Coates P.; Men Y.Tensile Deformation of Oriented Poly(ε-caprolactone) and Its Miscible Blends with Poly(vinyl methyl ether).Macromolecules2013, 46, 6981–6990. Google Scholar 42. Defize T.; Thomassin J.-M.; Alexandre M.; Gilbert B.; Riva R.; Jérôme C.Comprehensive Study of the Thermo-Reversibility of Diels-Alder Based PCL Polymer Networks.Polymer2016, 84, 234–242. Google Scholar 43. Zubkiewicz A.; Szymczyk A.; Paszkiewicz S.; Jędrzejewski R.; Piesowicz E.; Siemiński J.Ethylene Vinyl Acetate Copolymer/Halloysite Nanotubes Nanocomposites with Enhanced Mechanical and Thermal Properties.J. Appl. Polym. Sci.2020, 137, 49135. Google Scholar 44. Hoffendahl C.; Duquesne S.; Fontaine G.; Taschner F.; Mezger M.; Bourbigot S.Decomposition Mechanism of Fire Retarded Ethylene Vinyl Acetate Elastomer (EVA) Containing Aluminum Trihydroxide and Melamine.Polym. Degrad. Stab.2015, 113, 168–179. Google Scholar Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentVolume 4Issue 9Page: 3014-3022Supporting Information Copyright & Permissions© 2021 Chinese Chemical SocietyKeywordstemperature responsespolymer stretchingvibration-induced emissionmicroscopic visualizationphotoluminescent regulationAcknowledgmentsThe authors thank Dr. T. Jiang for his helpful discussions. Downloaded 1,618 times PDF DownloadLoading ...