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A Highly Stretchable Polyacrylonitrile Elastomer with Nanoreservoirs of Lubricant Using Cyano-silver Complexes Songlin Zhang, Ayou Hao, Zhe Liu, Jin Gyu Park, and Richard Liang Nano Lett., Just Accepted Manuscript • DOI: 10.1021/acs.nanolett.9b01055 • Publication Date (Web): 15 May 2019 Downloaded from http://pubs.acs.org on May 15, 2019

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A Highly Stretchable Polyacrylonitrile Elastomer with Nano-reservoirs of Lubricant Using Cyanosilver Complexes Songlin Zhang*, Ayou Hao, Zhe Liu, Jin Gyu Park*, and Richard Liang High-Performance Materials Institute, Department of Industrial and Manufacturing Engineering, FAMU-FSU College of Engineering, Florida State University, 2005 Levy Ave., Tallahassee, FL 32310, USA ABSTRACT: Stretchable materials are indispensable for applications such as deformable devices, wearable electronics and future robotics. However, designs for new elastomers with high stretchability has undergone only limited research. Here we have fabricated highly stretchable Ag+/polyacrylonitrile elastomer with nano-reservoirs of lubricant using cyano-silver complexes. The prepared products feature nano-confinement structures of lubricant surrounded by polymer chains with coordination bond through chelates of cyano-silver, resulting in an enhanced stretchability of more than 600% from 2%. The elastomeric properties were investigated, and a mechanical response model was proposed, which explained the structural evolution including the polymer chain fluidity under external deformation. Also, the easy breakage and dynamic reformation of cyano-silver coordination complexes promises a strain

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recovery under various stretching conditions. This elastomer itself can directly work as sensors and open path to alternative substrates for soft electronics development. KEYWORDS: polyacrylonitrile elastomer, cyano-silver complexes, coordination bond, stretchable electronics, strain sensors, electronic skins

The next-generation of electronics including medical products, flexible displays, and soft robotics that are capable of being flexible, wearable, and stretchable,1-3 place great demands on elastic materials. In fact, most devices are a combination of elastic substrates and active materials. Despite tremendous progress in the device fabrication, the achievements of past and current research are preponderantly associated with device performance improvements such as the electrical conductivity optimization of soft sensors using delicate micro-/macro-structure4 or different conductive fillers.5 Multiple sensing capabilities have also been reported.6 Polydimethylsiloxane (PDMS), poly(styrene-butadiene-styrene) (SBS), polystyrene-block-poly(ethylene-ran-butylene)block-polystyrene (SEBS), polyurethane (PU), and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are the most commonly used elastic substrates or encapsulating materials for the developments of soft electronics based on the literature survey.2, 7, 8 These substrates are good and have been thoroughly investigated. Although the expansion of new elastic materials for soft electronics could greatly diversify the product fabrication processes and accelerate realizing future integrated devices with multiple functionalities, studies that address the development of soft matrix materials themselves are still limited.9, 10 General routes such as adding softeners or plasticizers during elastomer manufacturing to improve stretchability have the issue of evaporation or bleeding of plasticizer over time.11 To avoid this


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flip-side effect, polymers with a glass transition temperature (Tg) significantly lower than their working temperature may achieve the required stretchability. Additionally, sufficient mechanical strength are also required for elastomers which can be realized using cross-links between polymer chains such as polyrotaxane (a cross-linking agent) for the system of ethylene glycol dimethacrylate (EGDMA)10 and others.1, 7 Unfortunately, the high density of cross-links usually bring a trade-off between strength and stretchability for elastomers1 due to increased stiffness (Young’s modulus), which may sacrifice the softness of elastomers when being integrated with wearable electronics. On the other hand, unique microstructures with special architecture design (e.g.: cellular-like geometry) are widely used to provide products with good compressibility and stretchability for both polymer and non-polymer materials.4, 8, 12,

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Nevertheless, realizing the

benefits of elastomers with strength from high cross-link density, stretchability from both low Tg and elaborated microstructures is still a challenge. Here we present a new soft and highly stretchable elastomer with improved attributes including a low Tg below zero and unique microstructure which are favorable for stretchability, along with highly coordination-bonded networks, which adds strength. This elastomer consists of commercially available semicrystalline polyacrylonitrile (PAN) and dimethylformamide (DMF) using metal-ligand bindings of cyano-silver ([Ag(-C≡N)x]+) complexes. These complex bindings between silver ion and nitrile group make the PAN chains randomly interconnected with a cellularlike structure. The structure has two phases with DMF nanoconfined in cells (nano-reservoirs), of which the walls consist of PAN chains with coordination bond. The nanoconfined (or trapped) DMF molecule within nano-reservoirs serves as a lubricant to provide an excellent fluidity of PAN polymer chains when under external deformation. Furthermore, the cyano-silver complexes are easily broken under external force and re-formation can achieve at original or neighboring sites


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when released. More importantly, this new elastomer can be directly used as sensors without any additional functional fillers such as nanocarbon materials, liquid metals or silver nanoparticles,3, 14-16

which make it a good candidate as soft substrate materials for future electronic device

fabrications.17, 18 Fabrication of Ag+/PAN elastomers Fabricating Ag+/PAN elastomers requires only a mixture of PAN solution in DMF and AgNO3. The interactions between Ag(Ⅰ) from the ionization of AgNO3 and N from the nitrile group on PAN chains form the coordination bond of cyano-silver complexes (Figure 1A and 1B).19 PAN polymer and AgNO3 crystals can be dissolved in DMF solvent. Thus, the as-prepared solutions with and without AgNO3 were both transparent without any aggregates (Figure 1C) and possessed a low viscosity (Video S1). Over time, the color of the Ag+/PAN solution at room temperature changed gradually from transparent to light brown, and then to dark-red (Figure S1). Finally, a viscous Ag+/PAN gel was obtained (Figure 1C, Video S1). In this study, to accelerate the coordination bonding process between Ag(Ⅰ) and N (-C≡N), the process was conducted in 50 °C environment. The corresponding gel properties with basic characterizations are listed in Table S1. Elastomer films with various mass ratios, R(x) (x, the ratio of AgNO3:PAN in weight) is shown in Figure S2. See Table S2 in supplementary materials for more details on the compositions of elastomers with various R(x). Compared to the average 2 % elastic strain of pure PAN film with R(0) in Figure 1D (without AgNO3, see Figure S3 for the elastic deformation behavior), the Ag+/PAN elastomer with R(1.0) showed a surprisingly high stretchability beyond 600% (Figure 1E, Video S2), which corresponds to an improvement of more than two orders of magnitude.


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Figure 1. Fabrication of extremely stretchable polyacrylonitrile elastomer. (A) The stretchable polyacrylonitrile film was made from a mixture solution containing PAN, DMF, and AgNO3. (B) Illustration of the microstructure based on the interactions between PAN chains, DMF, and silver ions during the solvent drying process. (C) The as-prepared PAN solution and Ag+/PAN mixture. Ag+/PAN mixture behaved as a dark-red solid gel after cross-linking, as compared to the transparent PAN solution. (D) Digital images of PAN film before stretching (initial) and after breakage (~ 2% elastic strain). (E) Ag+/PAN film was stretched to 600% strain.

Stretchability of Ag+/PAN elastomers Figure 2A plots the uniaxial test results of Ag+/PAN elastomers with various R(x). The pure PAN film with R(0), showed an elastic and plastic deformation under external force and reached a maximum failure strain of ~ 60%. However, the elastic deformation was only at 2 % (Figure S3). However, with the incorporation of Ag(Ⅰ), the Young’s modulus significantly decreased from ~


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2100 MPa for PAN film with R(0) to ~ 34 MPa for Ag+/PAN elastomer R(0.5).The stretchability was significantly improved more than 130 times, up to ~ 230%. By further raising the of R(x), the Young’s modulus kept decreasing to 1.4 MPa for elastomers with R(1.1) in this study (Figure 2B). As expected, a steady increase of stretchability was observed, reaching to a maximum value of ~ 720% (360 times improvement) for elastomer with R(1.1) in Figure 2B. For instance, the elastomer with R(1.0) had a smaller stretchability of ~ 600% (300 times improvement), and higher Young’s modulus of ~ 2.2 MPa, compared to the sample with R(1.1). All elastomers can be easily deformed to a desired stretching percentage with a small external force except the one with R(0 (see video S2 for the stretching demonstration). The maximum engineering stress of elastomers with R(1.0) and R(1.1) were in the range of only 2-3 MPa. Higher ratios beyond R(1.1) resulted in a very sticky film under the current experimental conditions, which was difficult to handle with for the following tests. Thus, for this study, elastomer with R(1.0) was selected as the study object unless otherwise specified. Regardless, this sticky property of R(x) beyond 1.1 could be further utilized to enable epidermal electronics, such as skin-like devices with other functional fillers,7 which will be the subject of future studies. Additionally, not only was the ratio R(x) important (see supplementary text and Figure S4 for more details about the effects of R(x) on the stretchability), but also the drying temperature during elastomer fabrication and test condition (e.g., test speed, S) were critical in determining the mechanical response.20 For instance, elastomers dried at 70 °C possessed a smaller stretchability, yet higher Young’s modulus (Figure S5). And the higher the test speed S, the higher (or smaller) the Young’s modulus (or the stretchability) (Figure 2C, Figure S6 and Figure S7).


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Figure 2. The mechanical stretchability and microstructure of Ag+/PAN elastomer. (A) The stretchability of Ag+/PAN elastomers as a function of the ratio R(x) (from R(0) to R(1.1)), test speed, S = 5 mm·min-1. (B) Young’s modulus and stretchability data extracted from curves in (A) with the obvious trend of a decrease (or increase) of the modulus (or stretchability) as the increase of ratio, R(x). (C) Test speed (S) dependence of stretchability and Young’s modulus of Ag+/PAN elastomer with R(1.0), increasing from S = 5 mm·min-1 to S = 100 mm·min-1. (D) FTIR of different elastomers with an absorption peak at 2243 cm-1 (-C≡N). (E) EDX data of line-scan profile through thickness of the elastomer showed the homogeneous distribution of silver. (F) SEM image of the cross-section with no microscale Ag particles observed. (G) HRTEM image displayed no silver particles at the nanoscale (inset is the FFT with no diffraction pattern of crystalline silver); the white arrows marked the possible cyano-silver complex rich centers. (H) STEM EDX mapping of


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the clear pattern of cyano-silver complex center (Ag Lα) with C, N, and O element homogeneously surrounded. (I) The enlarged area of the inset (the cross-section of elastomer with R(1.0) dried at 90 °C) which showed densely arranged cells (pointed by black arrows).

The cyano-silver complexes were confirmed from the FTIR data in Figure 2D (see Figure S8 for the full spectra). The vibration of triple bond nitrile (-C≡N) group was observed at 2243 cm-1 for all samples (from R(0) to R(1.1)).21 However, Ag+/PAN elastomers from R(0.5) to R(1.1) displayed a relatively broad peak, compared to PAN film with R(0), due to the coordination of Ag(Ⅰ) to the nitrogen of -C≡N (see Figure 1B for the illustration of cyano-silver complexes). A slight shoulder at 2263 cm-1 was recorded because of the changed chemical environment of -C≡N by the chelation of Ag(Ⅰ), which resulted in a lower transmission (%) and higher wave number, compared to the -C≡N on PAN backbone.22 The complexes were verified to be spatially homogeneous throughout the sample from the through-thickness EDX line-scan profile of silver element in the elastomer (Figure 2E) (see Figure S9 and S10 for more details about the elemental composition and distribution of samples with R(0) and R(1.0)). No observable silver particles were found either at microscale from the SEM in Figure 2F, nor at nanoscale from the HRTEM in Figure 2G (in the Figure 2G inset, no 2D diffraction pattern of silver crystals was observed from the FFT). No further evidence for the existence of silver particles was extracted from the X-ray scattering data, which should present as scattering peaks in the intensity-2θ plot (Figure S11A) due to the crystallinity. Therefore, this confirmed the existence of ionic state Ag+ which offers the capacity to adopt electrons from nitrogen (-C≡N), resulting in the cyano-silver complexes, as depicted in Figure 1B. The black dots marked by white arrows could be possibly recognized as the cyano-silver complex rich centers, which had a higher average atomic number (Ag), as compared to surrounding areas


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of most light elements including C, N, and O. This assumption was further verified by STEM EDX mapping of the black dot areas, which displayed a clear pattern of cyano-silver complex rich centers in Figure 2H (see Figure S12 for STEM BF and ADF images with their corresponding EDX spectrum). The internal structure of elastomers was further confirmed and illustrated in Figure S13, by varying the drying conditions during elastomer preparation. When drying at 90 °C, a microstructure of Ag+/PAN elastomer in Figure 2I (enlarged area from the black square area in the inset of cross-section) confirmed the nanoscale cells (marked by black arrows). These cells were nano-reservoirs for DMF (see Figure S13 for more detailed discussions on internal structures), which can assist the fluidity of PAN chains when under external deformation. Large cells were observed for elastomers dried at higher temperature of 150 °C, which was a result of merging effect of small cells during DMF evaporation (Figure S13). The strain history influenced the stretchability recovery during the cyclic stretching-releasing tests, as shown in Figure 3A. Complete recovery of strains were observed at time intervals of 10 min between each consecutive cycle when the external stretching percentage was less than 200% (cycle #1 to #4 in Figure 3B, enlarged from Figure 3A in the strain range of 100%). In addition, no change was observed for Young’s modulus in the first four cycles (Figure 3C). This indicated the mechanical resilience of coordination bonded polymer chains and full recovery of internal microstructure when subjected to smaller strains (< 200%). The following large stretching percentage (200-500% in this study) resulted in the decrease of Young’s modulus (Figure 3C) and residual strain was observed (cycle #5 to #7 in Figure 3B). The cyclic tests at a 200% strain (Figure 3D) demonstrated that with large strain history, longer time interval (e.g., 30min in Figure 3E) was needed for each cycle to recover to its original status (Figure 3F). Nevertheless, in this study, low glass transition temperature (Tg) (Figure S14) and unique internal structure (Figure S13) favored


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the ultrahigh stretchability of as-prepared elastomers. Additionally, viscoelastic behavior of elastomers demonstrated a good chain fluidity with a high tan delta (large loss modulus, Figure S7). Furthermore, deformation with residual strain was observed for samples stretched to 600% even after an interval of 24 hours (Figure S15). The stress relaxation indicates the breakage and dynamic re-formation of cyano-silver complexes at new sites (Figure 3G).20, 23, 24

Figure 3. Cyclic stretching and stress relaxation of Ag+/PAN elastomers with R(1.0) showing mechanical hysteresis and recovery. (A) Consecutive stretching-releasing cycles of elastomer with interval time of 10 min, showing large mechanical hysteresis as maximum strain of each cycle increased from 20% to 500%; S = 10 mm·min-1. (B) Enlarged area of (A) in the strain range of 0100%, including consecutive cycles of #1 to #7 (the corresponding maximum strain of 20% to 500%, respectively). (C) The extracted engineering modulus versus calculated strain recovery at each cycle, showing neglectable change in modulus (when maximum strain was less than 400%)


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and 100% strain recovery (when maximum strain was less than 200%. (D) Strain-history dependence of strain recovery with varying time interval. After four consecutive cycles of stretching-releasing, the fifth cycle (#5 in E, with interval time of 30 min) still showed a completely recovered strain and mechanical stress (#1 and #5 overlapped with each other, shown in (D)). (F) Digital images of samples before stretching (the initial), 200% strain (the stretching in cycle #5), and the following different recovery status (the releasing in cycle #5) at different time (from 0 to 30 min). (G) Stress relaxation showing the breakage and re-formation of cyano-silver complexes of Ag+/PAN elastomer.

Structural evolution of Ag+/PAN elastomers The internal microstructure evolution of the Ag+/PAN elastomers under continuous external deformation was monitored using small angle X-ray scattering (SAXS) with in-situ stretching. The 2D scattering pattern corresponding to different stretching was isotropic when strain was 0%, 50%, 100% as shown in Figure 4A. And the anisotropic feature started to show up slightly from 200% strain due to the gradual alignment of polymer chain under uniaxial stretching and became significantly prominent when stretching to even higher percentage (300%-600%). Quantitatively, the degree of alignment (𝑓) was calculated using Herman’s orientation equation.25 Based on the azimuthal angle scan data from 0° to 90° (Figure 4B), the extracted degree of alignment data is plotted in Figure 4C. While the stretching percentage was lower than 200%, nearly no alignment change was observed (e.g.: similar value of 𝑓, ~0.08 was obtained for 0%, 50% and 100% strain). Once the slight alignment degree of 0.21 at 200% appeared, it kept increasing up to ~ 0.7 for 500% and 600% strain. The evolution of alignment degree coincided with the microstructure (Figure 2I


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and Figure S13) and the mechanical behavior (Figure 2A and Figure 4C) of Ag+/PAN elastomer. Figure 4D schematically shows the illustration of its structural changes under various strain.

Figure 4. The internal structural evolution of Ag+/PAN elastomer using SAXS and the proposed mechanism for structural changes under various stretching percentage. (A) The 2D scattering patterns of elastomers with R(1.0) when being stretched to various strains. (B) The azimuthal scan integrated from the 2D scattering patterns in (A), from -90° to 90°. (C) The calculated alignment degree data based on the azimuthal scan in (B) using Herman’s orientation equation. The corresponding stresses at different strains are also displayed. (D) The microstructure evolution of Ag+/PAN elastomer including nano-reservoir deformation and polymer chain alignment under uniaxial stretching. Low stretching resulted in only nano-reservoir deformation and chain movement with a full strain recovery when releasing (< 200%). High stretching caused both nano-


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reservoir deformation and chain alignment with a residual strain when releasing due to chain sliding (> 200%).

Electrical response of Ag+/PAN elastomer as a sensor Due to the low Young’s modulus, Ag+/PAN elastomer can be easily deformed to a designed amplitude, which stands it out as a soft electronic for future robotics. A quick demonstration for the sensibility as a strain sensor was shown in video S3 (see Table S4 for the detailed sheet resistance of elastomers with various R(x)). The excellent stable electrical response was recorded under stretching-releasing cycles (50% strain) in Figure 5A. As a proof-of-concept, a “skin” was demonstrated to effectively respond to the air blow from mouth as shown in Figure 5 B and C. It can even timely and effectively detect the air blow based on the depth and speed (video S4). The excellent electromechanical response can be ascribed to the conductive property of Ag+/PAN elastomer, which is possibly induced by the cyano-silver complex center formed conductive pathway and the electron transfer between Ag+ and DMF.26 This new elastomer, without additional conductive fillers such silver particles or nanocarbon materials, exhibited an impressive sensibility as a strain sensor and electronic “skin”. Additionally, the performance of present Ag+/PAN elastomer is highly tunable using different ratio, R(x). Thus, the electro-mechanical response of this new elastomer itself or being used as substrates with other functional filters can potentially be further optimized for specific requirements, which will be the focus of our future studies. Conclusions In this study, we developed a new strategy to achieve highly stretchable polymer elastomer using only PAN (polymer), DMF (solvent), and AgNO3. The PAN chains with coordination bond by


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cyano-silver complexes and their unique cellular-like internal structure with nano-reservoirs of DMF endows the polymer chain large fluidity. The breakage and dynamic reformation of coordination complexes between Ag(Ⅰ) and nitrogen (-C≡N) ensured a good stretchability and strain recovery under various deformation. This new elastomer can be directly used as sensors or integrated with other functional fillers for specific applications. Such initiated elastomer, first-ofits-kind with an integration of high coordination bond density and high stretchability, sheds light on the new designs of soft products, wearable electronics, and future robotics.

Figure 5. The electrical response of Ag+/PAN elastomer subject to external stimuli. (A) The voltage change of an elastomer under cyclic tensile stretching-releasing (50% strain), showing a robust performance. (B) Experimental set-up to access the sensibility of Ag+/PAN elastomer under external subtle stimuli (e.g.: air blow). Four electrodes attached to corners are used to apply current and detect voltage change. (C) The digital image of a sample with four copper electrodes attached.


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(D) Voltage change jumped abruptly when air blow was present, implying a fast response and high sensibility.

Associated content Supporting Information. The supporting information is available free of charge on the ACS Publications website at http://pubs.acs.org. Additional details on sample fabrication and various test methods. Supplementary text on the two-phase structure formation and polymer chain fluidity under stretching. Table showing the compositions of various samples. Figures showing the digital image of elastomers, and their strain-stress curves, TGA, DSC, FT-IR, X-ray scattering analysis, SEM EDX mapping and STEM BF and ADF images. Videos showing the stretchability and sensibility of elastomers. Author Information Corresponding Authors *E-mail: [email protected] (Songlin Zhang) *E-mail: [email protected] (Jin Gyu Park) ORCID Songlin Zhang: 0000-0002-0554-6737 Jin Gyu Park: 0000-0002-9046-1905 Author contribution


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S.Z. conceived the idea. S.Z. and J.G.P. designed the experiments. S.Z. fabricated the elastomers. S.Z., A.H. and J.G.P. performed the characterizations, acquired and interpreted the data. S.Z. and J.G.P. proposed the microstructure model of the elastomers. S.Z wrote an initial version of the manuscript and all authors reviewed it. Funding This work was supported by AFOSRFA9550-17-1-0005 and China Scholarship Council (CSC no. 201506630022). Acknowledgment Authors thank Yi-Feng Su for HTTEM images and STEM EDX mapping, and Frank Allen for manuscript editing. S.Z. is grateful for Yinnan Zhang’s wholehearted support. References 1. Li, C. H.; Wang, C.; Keplinger, C.; Zuo, J. L.; Jin, L.; Sun, Y.; Zheng, P.; Cao, Y.; Lissel, F.; Linder, C.; You, X. Z.; Bao, Z. Nat Chem 2016, 8, (6), 618-624. 2. Wang, S.; Xu, J.; Wang, W.; Wang, G. N.; Rastak, R.; Molina-Lopez, F.; Chung, J. W.; Niu, S.; Feig, V. R.; Lopez, J.; Lei, T.; Kwon, S. K.; Kim, Y.; Foudeh, A. M.; Ehrlich, A.; Gasperini, A.; Yun, Y.; Murmann, B.; Tok, J. B.; Bao, Z. Nature 2018, 555, 83-88. 3. Markvicka, E. J.; Bartlett, M. D.; Huang, X.; Majidi, C. Nature Materials 2018, 17, (7), 618-624. 4. Liu, Z.; Fang, S.; Moura, F.; Ding, J.; Jiang, N.; Di, J.; Zhang, M.; Lepró, X.; Galvão, D.; Haines, C. Science 2015, 349, (6246), 400-404. 5. Choi, S.; Han, S. I.; Jung, D.; Hwang, H. J.; Lim, C.; Bae, S.; Park, O. K.; Tschabrunn, C. M.; Lee, M.; Bae, S. Y.; Yu, J. W.; Ryu, J. H.; Lee, S. W.; Park, K.; Kang, P. M.; Lee, W. B.; Nezafat, R.; Hyeon, T.; Kim, D. H. Nat Nanotechnol 2018, 13, (11), 1048-1056. 6. Son, D.; Kang, J.; Vardoulis, O.; Kim, Y.; Matsuhisa, N.; Oh, J. Y.; To, J. W.; Mun, J.; Katsumata, T.; Liu, Y.; McGuire, A. F.; Krason, M.; Molina-Lopez, F.; Ham, J.; Kraft, U.; Lee, Y.; Yun, Y.; Tok, J. B.; Bao, Z. Nat Nanotechnol 2018, 13, (11), 1057-1065. 7. Jeong, S. H.; Zhang, S.; Hjort, K.; Hilborn, J.; Wu, Z. Adv Mater 2016, 28, (28), 58305836. 8. Lee, Y. Y.; Kang, H. Y.; Gwon, S. H.; Choi, G. M.; Lim, S. M.; Sun, J. Y.; Joo, Y. C. Adv Mater 2016, 28, (8), 1636-1643. 9. Wang, Y.; Zhu, C.; Pfattner, R.; Yan, H.; Jin, L.; Chen, S.; Molina-Lopez, F.; Lissel, F.; Liu, J.; Rabiah, N. I.; Chen, Z.; Chung, J. W.; Linder, C.; Toney, M. F.; Murmann, B.; Bao, Z. Science Advances 2017, 3, (3), e1602076. 10. Gotoh, H.; Liu, C.; Imran, A. B.; Hara, M.; Seki, T.; Mayumi, K.; Ito, K.; Takeoka, Y. Science Advances 2018, 4, (10), eaat7629. 11. Kayser, L. V.; Lipomi, D. J. 2019, 31, (10), 1806133.


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12. Gao, H. L.; Zhu, Y. B.; Mao, L. B.; Wang, F. C.; Luo, X. S.; Liu, Y. Y.; Lu, Y.; Pan, Z.; Ge, J.; Shen, W.; Zheng, Y. R.; Xu, L.; Wang, L. J.; Xu, W. H.; Wu, H. A.; Yu, S. H. Nat Commun 2016, 7, 12920. 13. Song, P.; Qin, H.; Gao, H. L.; Cong, H. P.; Yu, S. H. Nat Commun 2018, 9, (1), 2786. 14. Matsuhisa, N.; Kaltenbrunner, M.; Yokota, T.; Jinno, H.; Kuribara, K.; Sekitani, T.; Someya, T. Nat Commun 2015, 6, 7461. 15. Zhang, S.; Park, J. G.; Nguyen, N.; Jolowsky, C.; Hao, A.; Liang, R. Carbon 2017, 125, 649-658. 16. Zhang, S.; Hao, A.; Nguyen, N.; Oluwalowo, A.; Liu, Z.; Dessureault, Y.; Park, J. G.; Liang, R. Carbon 2019, 144, 628-638. 17. Wang, J.; Cai, G.; Li, S.; Gao, D.; Xiong, J.; Lee, P. S. Advanced Materials 2018, 30, (11). 18. Lee, J.; Shin, S.; Lee, S.; Song, J.; Kang, S.; Han, H.; Kim, S.; Kim, S.; Seo, J.; Kim, D.; Lee, T. ACS Nano 2018, 12, (5), 4259–4268. 19. Gerasimchuk, N.; Esaulenko, A. N.; Dalley, K. N.; Moore, C. Dalton Transactions 2010, 39, (3), 749-764. 20. Filippidi, E.; Cristiani, T. R.; Eisenbach, C. D.; Waite, J. H.; Israelachvili, J. N.; Ahn, B. K.; Valentine, M. T. Science 2017, 358, (6362), 502-505. 21. Karbownik, I.; Fiedot, M.; Rac, O.; Suchorska-Woźniak, P.; Rybicki, T.; Teterycz, H. Polymer 2015, 75, 97-108. 22. Liu, Q.; Chen, N.; Bai, S.; Li, W. RSC Advances 2018, 8, (5), 2804-2810. 23. Zhang, X.; Liu, J.; Zhang, Z.; Wu, S.; Tang, Z.; Guo, B.; Zhang, L. ACS Appl Mater Interfaces 2018, 10, (28), 23485-23489. 24. Xu, J.; Chen, W.; Wang, C.; Zheng, M.; Ding, C.; Jiang, W.; Tan, L.; Fu, J. Chemistry of Materials 2018, 30, (17), 6026-6039. 25. Jolowsky, C.; Sweat, R.; Park, J. G.; Hao, A.; Liang, R. Composites Science and Technology 2018, 166, 125-130. 26. Sun, L.; Hendon, C. H.; Dinca, M. Dalton Trans 2018, 47, (34), 11739-11743.


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For Table of Contents Only

An effective and simple method for the fabrication of polyacrylonitrile elastomer is developed, by only drying the solution mixture of silver ion, polyacrylonitrile, and dimethylformamide, achieving an ultrahigh stretchability from 2% to more than 600% due to the unique structure of nano-reservoirs using cyano-silver complexes. This elastomer is electromechanically sensitive and open alternative paths for new stretchable electronics development.


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A Highly Stretchable Polyacrylonitrile Elastomer ... - ACS Publications

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