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Enhanced flexibility of conductive layer with inkjet-imprinted microstructure surface
Journal Pre-proofs Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Chenghu Yun, Fuqiang Chu, Bo Cui, Xin Wang, Guangping Liu, Jiazhen Sun PII: DOI: Reference:
S0167-577X(20)30166-X https://doi.org/10.1016/j.matlet.2020.127461 MLBLUE 127461
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
13 December 2019 21 January 2020 4 February 2020
Please cite this article as: C. Yun, F. Chu, B. Cui, X. Wang, G. Liu, J. Sun, Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface, Materials Letters (2020), doi: https://doi.org/10.1016/j.matlet. 2020.127461
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2020 Published by Elsevier B.V.
Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Chenghu Yun,a Fuqiang Chu,a,* Bo Cui,a Xin Wang,b Guangping Liua and Jiazhen Suna,* a State
Key Laboratory of Biobased Material and Green Papermaking, Key Laboratory of Pulp and
Paper Science & Technology of Ministry of Education/Shandong Province, Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, School of Light Industry and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China E-mail: [email protected]; [email protected] b
School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology,
Xi’an 710048, China Abstract: Flexible electronic device plays a crucial role in realizing man-machine interaction and developing wearable devices. Maintaining electrical conductivity with flexibility is crucial in the research. In this work, microstructures, such as points, lines and crossed lines, were fabricated based on viscoelastic substrate by inkjet-imprinting. The prepared microstructures could enhance the flexibility of conductive layer on the surface. The results showed that the electrode had a good conductivity and stability during bending. Different structures showed different performance. It had a maximum strain of the crossed line microstructure electrode which increased to 90%. Therefore, this work provides a facile way for fabricating flexible electrode. Keyword: microstructure; surface; electrical properties; sensors 1. Introduction Flexible electronic devices have caught people’s focus for their ability to work under the deformation. [1] They are widely used in electronic-skin [2], soft robot [3] and sensor [4]. 1
Therefore, it is significant to study the electrode with good flexibility. Researchers used flexible materials such as metal nanowires [5], graphene [6] and conductive polymers [7] to make the device flexible. However, due to the limitations of the material itself, the flexibility was limited. There are three methods for preparing flexible electrodes: (1) A viscoelastic material was used as substrate [8]; (2) The bionic structure [9, 10] was used as the template; (3) The microstructure was prepared by the method such as photolithography [11]. However, these methods required expensive equipment or cumbersome steps. Herein, this work fabricated the microstructure by a simple method of inkjet-imprinting. [12] The flexible electrode was obtained by thermal evaporation. Results showed that microstructures played a positive role in maintaining electrical conductivity. Non-microstructure electrodes lost conductivity when strain exceeds 10%, while electrodes with point microstructure could withstand increase to 40%. Due to the anisotropy, parallel to the line microstructure electrode when bent the device could withstand 75% strain, and vertical to the line structure only could withstand strain decrease to 7%. The crossed line electrode had the excellent performance that could withstand 95% strain. 2. Experiment 2.1 Material Polydimethylsiloxane (PDMS): (Sylgard 184, Dow Corning), Polyethylene terephthalate (PET): (Beijing Daxiang Plastic Co., Ltd.), Ethanol: (Beijing Chemical Co., Ltd.), Polyacrylic acid: (PAA, Sigma-Aldrich, USA). 2.2 Fabricated of Flexible Microstructure Electrode PDMS was spin-coated (700 rpm for 30 s, then 2000 rpm for 10 s) on PET (2 cm × 2 cm), to 2
have a thickness about 60μm, and pre-cured 15-20 minutes at 70 °C. The PAA solution, sacrificial ink, had a mass fraction of 10% (volume ratio of deionized water to ethanol of 20:80, Fig. S1). The printing pitch was 0.2mm. After the printing was finished, the printed substrate was cured at 70 °C for 2h. Then the surface was washed several times with deionized water. The microstructure surface was modified by air plasma for 30s. A layer of gold was deposited on the surface by ion sputtering. The thickness was about 200Å. 2.3 Characterization Characterization of microstructure surface topography used a polarizing microscope (NP800TRF, China) and scanning electron microscope (Rugulus 8220, Japan). Performance of the test used an electrochemical workstation (Metrohm PGSTAT 302N, Switzerland). 3. Results and Analysis 3.1 Morphology of Microstructure
Fig. 1. (a) Illustration of the fabrication for the microstructure to enhance the flexibility of conductive layer. (b) Polarized micrograph of the point microstructure. (c) Polarized micrograph of the line microstructure. (d) Polarized 3
micrograph of the crossed line. (e) Scanning electron micrograph of the line microstructure. (f) High magnification scanning electron micrographs of the cross-section. (g) The left is the microstructure electrode before evaporation, and the right is the microstructure electrode after evaporation.
Fig. 1(a) was the process of preparing microstructure. Fig. 1(b)-(d) were polarized photomicrographs of points, lines and crossed lines respectively. Further, represented by the line microstructure to measure the geometry of the microstructure. The width of the line (high magnification in Fig. S2) was about 8-10μm as shown in Fig. 1(e). According to the high magnification of the cross-section in Fig. 1(f), the depth was about 2-3μm. A conductive layer was deposited on the surface by evaporation. The surface was modified by air plasma before deposition in order to increase the adhesion between the conductive layer and the surface. And Fig. 1(g) was flexible electrode after evaporation. 3.2 Enhanced Flexibility of the Electrode
Fig. 2. (a) The left is initial state microstructure electrode and the right is partial scanning electron micrographs of the surface. (b) The left is microstructure electrode after bending 500 times at 50% strain and the right is partial scanning electron micrographs of the surface. (c) Flexible test with point, line, and line microstructure electrodes. (d) Stability test at 25% strain and the upper right corner is a partial enlargement. 4
As shown in Fig. 2(a)-(b), there were some small cracks on the microstructure electrode surface but no conductive layer peeled off from the substrate after bending 500 times at 50% strain. Meanwhile non-microstructure electrode and microstructure electrode had very small differences in electrical conductivity without bending in Fig. S3. A non-microstructure electrode and a microstructure electrode were respectively used as a wire to illuminate the small bulb. Results showed that the non-microstructure electrode lost conductivity under slight strain (Video 1). The microstructure electrode could illuminate the small bulb when bending (Video 2). As shown in Fig. S4(a), flexibility of the electrode was tested with a transmission device, and testing processes of 25%, 50% and 75% strain were given respectively in Fig. S4(b)-(d). L0 was the original length of the microstructure electrode, and ∆L was the difference between the length of the electrode after bending and L0. R0 was the initial resistance value of the microstructure electrode. ∆R was the absolute value of the change in resistance after bending. As shown in Fig. 2(c), for the nonmicrostructure electrode, ∆R/R0 could reach 17% when the strain was 8%. While the strain increase to 10%, ∆R sharply increased and lost conductivity. The flexible electrode with point microstructure had a ∆R/R0 of no more than 50% at 40% strain. As to the flexible electrode of the line microstructure, the bending tests were performed under the situation of vertical and paralleled to the line microstructure respectively. It showed a large difference due to the anisotropy. When bending vertically to the line microstructure, the conductivity lost at 7% strain. In contrast, it exhibited good flexibility when paralleled to the line microstructure. Its maximum strain could reach 75%. For a flexible electrode with crossed line, when the strain reached 90%, it still maintained good conductivity. The microstructure electrode was tested for cyclic stability. As shown in Fig. 2(d), the ∆R was stable after dozens of bending. It could be seen from the above 5
data that the electrode with microstructure had better flexibility. The reasons could be attributed to the following: (1) The Young's modulus of PDMS and gold differs by several orders of magnitude. The combination of the two improves the conductive layer’s flexible properties; (2) The prepared microstructures provide better support when the conductive layer is bent. 3.3 Monitoring the Knuckle Activity
Fig. 3. Testing the changes in human joint activity using prepared sensor. (a) Current change when the knuckle bending at 30°. (b) Current change when the knuckle bending at 60°. (c) Current change when the knuckle bending at 90°. (d) The knuckle bending at 30°. (e) The knuckle bending at 60°. (f) The knuckle bending at 90°.
As shown in Fig. 3, the digital joints were used to test the prepared sensor. When bending 30° in Fig. 3(d), there was a significant current change in Fig. 3(a). And the current fluctuated significantly when bending at 60° in Fig. 3(e). However, after the recovery, the electrical conductivity recovered with hysteresis in Fig. 3(b). When bending 90° in Fig. 3(f), the current changed more widely. As shown in Fig. 3(c), when the shape was restored, the current exhibited a hysteresis of a few seconds and the current lost after recovery was within an acceptable range. 4. Conclusion In summary, the microstructures were prepared conveniently by inkjet-imprinting. Then the conductive layer was deposited on the surface. The prepared microstructure electrode exhibits excellent flexibility compared to the non-microstructure electrode. The maximum strain of the 6
point microstructure electrode could reach 40%. For the line microstructure electrode, bending under the situation of parallel and vertical to line microstructure showed a large difference. When the bending test was parallel to the microstructure, the maximum strain could reach 75%. The crossed line electrode had the largest strain that could reach 90%. The prepared electrode exhibited good flexibility and was expected to be used in wearable devices. Acknowledgement This work was supported by the National Natural Science Foundation of China (No. 21703110), the Key Research and Development Project of Shandong Province of China (No. 2017GGX80105, 2019GGX102037), the Foundation (No. KF201822) of Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education/Shandong Province of China, the Foundation (No. ZZ20190213, ZZ20190218) of State Key Laboratory of Biobased Material and Green Papermaking of China, the Project of International Cooperation Research Special Funds Program (No. QLUTGJHZ2018026) of Qilu University of Technology (Shandong Academy of Sciences) of China. References [1] S. L. Wang, J. Y. Oh, J. Xu, H. Tran, Z. N. Bao, Accounts Chem. Res. 51 (2018) 1033-1045. https://doi.org/10.1021/acs.accounts.8b00015. [2] J. Z. Sun, Y. Z. Guo, B. Cui, F. Q. Chu, H. Z. Li, Y. Li, M. He, D. Ding, R. P. Liu, L. H. Li, Y. L. Song, Appl. Surf. Sci. 445 (2018) 391-397. https://doi.org/10.1016/j.apsusc.2018.03.204. [3] Z. Y. Zhan, R. Z. Lin, V. T. Tran, J. N. An, Y. F. Wei, H. J. Du, T. Tran, W. Q. Lu, ACS Appl. Mater. Inter. 9 (2017) 37921-37928. https://doi.org/10.1021/acsami.7b10820. [4] L. L. Li, L. J. Pan, Z. Ma, K. Yan, W. Cheng, Y. Shi, G. H. Yu, Nano. Lett. 18 (2018) 33227
3327. https://doi.org/10.1021/acs.nanolett.8b00003. [5] J. Z. Sun, B. Cui, F. Q. Chu, C. H. Yun, M. He, L. H. Li, Y. L. Song, Nanomaterials 8 (2018) 528-552. https://doi.org/10.3390/nano8070528. [6] J. Martinez-Ligas, A. I. Oliva, M. Velazquez-Manzanares, C. R. Garcia, A. I. Mtz-Enriquez, J. Oliva, Mater. Lett. 253 (2019) 205-208. https://doi.org/10.1016/j.matlet.2019.06.071. [7] Y. Wang, C. X. Zhu, R. Pfattner, H. P. Yan, L. H. Jin, S. C. Chen, F. Molina-Lopez, F. Lissel, J. Liu, N. I. Rabiah, Z. Chen, J. W. Chung, C. Linder, M. F. Toney, B. Murmann, Z. N. Bao, Sci. Adv. 3 (2017) 1602076-1602085. https://doi.org/10.1126/sciadv.1602076. [8] Z. Y. Liu, D. P. Qi, P. Z. Guo, Y. Liu, B. W. Zhu, H. Yang, Y. Q. Liu, B. Li, C. G. Zhan, J. C. Yu,
B.
Liedberg,
X.
D.
Chen,
Adv.
Mater.
27
(2015)
6230-6237.
https://doi.org/10.1002/adma.201503288. [9] Y. B. Wan, Z. G. Qiu, Y. Hong, Y. Wang, J. M. Zhang, Q. X. Liu, Z. G. Wu, C. F. Guo, Adv. Electron. Mater. 4 (2018) 1700586-1700593. https://doi.org/10.1002/aelm.201700586. [10] B. Su, S. Gong, Z. Ma, L. W. Yap, W. L. Cheng, Small 11 (2015) 1886-1891. https://doi.org/10.1002/smll.201403036. [11] S. Kim, T. Y. Eom, M. Cho, K. Y. Song, C. H. An, H. J Lee, B. Hwang, Mater. Lett. 199 (2017) 196-199. https://doi.org/10.1016/j.matlet.2017.04.080. [12] J. Z. Sun, C. H. Yun, B. Cui, P. P. Li, G. P. Liu, X. Wang, F. Q. Chu, Polymers 10 (2018) 1209-1220. https://doi.org/10.3390/polym10111209.
8
Credit Author Statement Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Fuqiang Chu and Jiazhen Sun conceived of and designed the study work. Chenghu Yun acquired and analyzed the data. Bo Cui, Xin Wang and Guangping Liu analyzed and interpreted data. All authors wrote the manuscript and gave final approval for its publication.
9
Graphical Abstract Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Chenghu Yun, Fuqiang Chu,* Bo Cui, Xin Wang, Guangping Liu and Jiazhen Sun* Keyword: microstructure; surface; electrical properties; sensors
Microstructures, such as points, lines and crossed lines, were fabricated based on viscoelastic substrate by inkjet-imprinting. The prepared microstructures could enhance the flexibility of conductive layer on the surface. The results showed that the electrode had a good conductivity and stability during bending. It had a maximum strain which increased to 90%. Therefore, this work provides a facile way for fabricating flexible electrode.
10
Highlights · Microstructures were prepared by a simple method of inkjet-imprinting. · The flexible electrode could withstand 90% strain with the help of microstructure. · Using for monitor knuckle motion, flexible devices exhibited good performance.
11
S0167-577X(20)30166-X https://doi.org/10.1016/j.matlet.2020.127461 MLBLUE 127461
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
13 December 2019 21 January 2020 4 February 2020
Please cite this article as: C. Yun, F. Chu, B. Cui, X. Wang, G. Liu, J. Sun, Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface, Materials Letters (2020), doi: https://doi.org/10.1016/j.matlet. 2020.127461
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2020 Published by Elsevier B.V.
Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Chenghu Yun,a Fuqiang Chu,a,* Bo Cui,a Xin Wang,b Guangping Liua and Jiazhen Suna,* a State
Key Laboratory of Biobased Material and Green Papermaking, Key Laboratory of Pulp and
Paper Science & Technology of Ministry of Education/Shandong Province, Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, School of Light Industry and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China E-mail: [email protected]; [email protected] b
School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology,
Xi’an 710048, China Abstract: Flexible electronic device plays a crucial role in realizing man-machine interaction and developing wearable devices. Maintaining electrical conductivity with flexibility is crucial in the research. In this work, microstructures, such as points, lines and crossed lines, were fabricated based on viscoelastic substrate by inkjet-imprinting. The prepared microstructures could enhance the flexibility of conductive layer on the surface. The results showed that the electrode had a good conductivity and stability during bending. Different structures showed different performance. It had a maximum strain of the crossed line microstructure electrode which increased to 90%. Therefore, this work provides a facile way for fabricating flexible electrode. Keyword: microstructure; surface; electrical properties; sensors 1. Introduction Flexible electronic devices have caught people’s focus for their ability to work under the deformation. [1] They are widely used in electronic-skin [2], soft robot [3] and sensor [4]. 1
Therefore, it is significant to study the electrode with good flexibility. Researchers used flexible materials such as metal nanowires [5], graphene [6] and conductive polymers [7] to make the device flexible. However, due to the limitations of the material itself, the flexibility was limited. There are three methods for preparing flexible electrodes: (1) A viscoelastic material was used as substrate [8]; (2) The bionic structure [9, 10] was used as the template; (3) The microstructure was prepared by the method such as photolithography [11]. However, these methods required expensive equipment or cumbersome steps. Herein, this work fabricated the microstructure by a simple method of inkjet-imprinting. [12] The flexible electrode was obtained by thermal evaporation. Results showed that microstructures played a positive role in maintaining electrical conductivity. Non-microstructure electrodes lost conductivity when strain exceeds 10%, while electrodes with point microstructure could withstand increase to 40%. Due to the anisotropy, parallel to the line microstructure electrode when bent the device could withstand 75% strain, and vertical to the line structure only could withstand strain decrease to 7%. The crossed line electrode had the excellent performance that could withstand 95% strain. 2. Experiment 2.1 Material Polydimethylsiloxane (PDMS): (Sylgard 184, Dow Corning), Polyethylene terephthalate (PET): (Beijing Daxiang Plastic Co., Ltd.), Ethanol: (Beijing Chemical Co., Ltd.), Polyacrylic acid: (PAA, Sigma-Aldrich, USA). 2.2 Fabricated of Flexible Microstructure Electrode PDMS was spin-coated (700 rpm for 30 s, then 2000 rpm for 10 s) on PET (2 cm × 2 cm), to 2
have a thickness about 60μm, and pre-cured 15-20 minutes at 70 °C. The PAA solution, sacrificial ink, had a mass fraction of 10% (volume ratio of deionized water to ethanol of 20:80, Fig. S1). The printing pitch was 0.2mm. After the printing was finished, the printed substrate was cured at 70 °C for 2h. Then the surface was washed several times with deionized water. The microstructure surface was modified by air plasma for 30s. A layer of gold was deposited on the surface by ion sputtering. The thickness was about 200Å. 2.3 Characterization Characterization of microstructure surface topography used a polarizing microscope (NP800TRF, China) and scanning electron microscope (Rugulus 8220, Japan). Performance of the test used an electrochemical workstation (Metrohm PGSTAT 302N, Switzerland). 3. Results and Analysis 3.1 Morphology of Microstructure
Fig. 1. (a) Illustration of the fabrication for the microstructure to enhance the flexibility of conductive layer. (b) Polarized micrograph of the point microstructure. (c) Polarized micrograph of the line microstructure. (d) Polarized 3
micrograph of the crossed line. (e) Scanning electron micrograph of the line microstructure. (f) High magnification scanning electron micrographs of the cross-section. (g) The left is the microstructure electrode before evaporation, and the right is the microstructure electrode after evaporation.
Fig. 1(a) was the process of preparing microstructure. Fig. 1(b)-(d) were polarized photomicrographs of points, lines and crossed lines respectively. Further, represented by the line microstructure to measure the geometry of the microstructure. The width of the line (high magnification in Fig. S2) was about 8-10μm as shown in Fig. 1(e). According to the high magnification of the cross-section in Fig. 1(f), the depth was about 2-3μm. A conductive layer was deposited on the surface by evaporation. The surface was modified by air plasma before deposition in order to increase the adhesion between the conductive layer and the surface. And Fig. 1(g) was flexible electrode after evaporation. 3.2 Enhanced Flexibility of the Electrode
Fig. 2. (a) The left is initial state microstructure electrode and the right is partial scanning electron micrographs of the surface. (b) The left is microstructure electrode after bending 500 times at 50% strain and the right is partial scanning electron micrographs of the surface. (c) Flexible test with point, line, and line microstructure electrodes. (d) Stability test at 25% strain and the upper right corner is a partial enlargement. 4
As shown in Fig. 2(a)-(b), there were some small cracks on the microstructure electrode surface but no conductive layer peeled off from the substrate after bending 500 times at 50% strain. Meanwhile non-microstructure electrode and microstructure electrode had very small differences in electrical conductivity without bending in Fig. S3. A non-microstructure electrode and a microstructure electrode were respectively used as a wire to illuminate the small bulb. Results showed that the non-microstructure electrode lost conductivity under slight strain (Video 1). The microstructure electrode could illuminate the small bulb when bending (Video 2). As shown in Fig. S4(a), flexibility of the electrode was tested with a transmission device, and testing processes of 25%, 50% and 75% strain were given respectively in Fig. S4(b)-(d). L0 was the original length of the microstructure electrode, and ∆L was the difference between the length of the electrode after bending and L0. R0 was the initial resistance value of the microstructure electrode. ∆R was the absolute value of the change in resistance after bending. As shown in Fig. 2(c), for the nonmicrostructure electrode, ∆R/R0 could reach 17% when the strain was 8%. While the strain increase to 10%, ∆R sharply increased and lost conductivity. The flexible electrode with point microstructure had a ∆R/R0 of no more than 50% at 40% strain. As to the flexible electrode of the line microstructure, the bending tests were performed under the situation of vertical and paralleled to the line microstructure respectively. It showed a large difference due to the anisotropy. When bending vertically to the line microstructure, the conductivity lost at 7% strain. In contrast, it exhibited good flexibility when paralleled to the line microstructure. Its maximum strain could reach 75%. For a flexible electrode with crossed line, when the strain reached 90%, it still maintained good conductivity. The microstructure electrode was tested for cyclic stability. As shown in Fig. 2(d), the ∆R was stable after dozens of bending. It could be seen from the above 5
data that the electrode with microstructure had better flexibility. The reasons could be attributed to the following: (1) The Young's modulus of PDMS and gold differs by several orders of magnitude. The combination of the two improves the conductive layer’s flexible properties; (2) The prepared microstructures provide better support when the conductive layer is bent. 3.3 Monitoring the Knuckle Activity
Fig. 3. Testing the changes in human joint activity using prepared sensor. (a) Current change when the knuckle bending at 30°. (b) Current change when the knuckle bending at 60°. (c) Current change when the knuckle bending at 90°. (d) The knuckle bending at 30°. (e) The knuckle bending at 60°. (f) The knuckle bending at 90°.
As shown in Fig. 3, the digital joints were used to test the prepared sensor. When bending 30° in Fig. 3(d), there was a significant current change in Fig. 3(a). And the current fluctuated significantly when bending at 60° in Fig. 3(e). However, after the recovery, the electrical conductivity recovered with hysteresis in Fig. 3(b). When bending 90° in Fig. 3(f), the current changed more widely. As shown in Fig. 3(c), when the shape was restored, the current exhibited a hysteresis of a few seconds and the current lost after recovery was within an acceptable range. 4. Conclusion In summary, the microstructures were prepared conveniently by inkjet-imprinting. Then the conductive layer was deposited on the surface. The prepared microstructure electrode exhibits excellent flexibility compared to the non-microstructure electrode. The maximum strain of the 6
point microstructure electrode could reach 40%. For the line microstructure electrode, bending under the situation of parallel and vertical to line microstructure showed a large difference. When the bending test was parallel to the microstructure, the maximum strain could reach 75%. The crossed line electrode had the largest strain that could reach 90%. The prepared electrode exhibited good flexibility and was expected to be used in wearable devices. Acknowledgement This work was supported by the National Natural Science Foundation of China (No. 21703110), the Key Research and Development Project of Shandong Province of China (No. 2017GGX80105, 2019GGX102037), the Foundation (No. KF201822) of Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education/Shandong Province of China, the Foundation (No. ZZ20190213, ZZ20190218) of State Key Laboratory of Biobased Material and Green Papermaking of China, the Project of International Cooperation Research Special Funds Program (No. QLUTGJHZ2018026) of Qilu University of Technology (Shandong Academy of Sciences) of China. References [1] S. L. Wang, J. Y. Oh, J. Xu, H. Tran, Z. N. Bao, Accounts Chem. Res. 51 (2018) 1033-1045. https://doi.org/10.1021/acs.accounts.8b00015. [2] J. Z. Sun, Y. Z. Guo, B. Cui, F. Q. Chu, H. Z. Li, Y. Li, M. He, D. Ding, R. P. Liu, L. H. Li, Y. L. Song, Appl. Surf. Sci. 445 (2018) 391-397. https://doi.org/10.1016/j.apsusc.2018.03.204. [3] Z. Y. Zhan, R. Z. Lin, V. T. Tran, J. N. An, Y. F. Wei, H. J. Du, T. Tran, W. Q. Lu, ACS Appl. Mater. Inter. 9 (2017) 37921-37928. https://doi.org/10.1021/acsami.7b10820. [4] L. L. Li, L. J. Pan, Z. Ma, K. Yan, W. Cheng, Y. Shi, G. H. Yu, Nano. Lett. 18 (2018) 33227
3327. https://doi.org/10.1021/acs.nanolett.8b00003. [5] J. Z. Sun, B. Cui, F. Q. Chu, C. H. Yun, M. He, L. H. Li, Y. L. Song, Nanomaterials 8 (2018) 528-552. https://doi.org/10.3390/nano8070528. [6] J. Martinez-Ligas, A. I. Oliva, M. Velazquez-Manzanares, C. R. Garcia, A. I. Mtz-Enriquez, J. Oliva, Mater. Lett. 253 (2019) 205-208. https://doi.org/10.1016/j.matlet.2019.06.071. [7] Y. Wang, C. X. Zhu, R. Pfattner, H. P. Yan, L. H. Jin, S. C. Chen, F. Molina-Lopez, F. Lissel, J. Liu, N. I. Rabiah, Z. Chen, J. W. Chung, C. Linder, M. F. Toney, B. Murmann, Z. N. Bao, Sci. Adv. 3 (2017) 1602076-1602085. https://doi.org/10.1126/sciadv.1602076. [8] Z. Y. Liu, D. P. Qi, P. Z. Guo, Y. Liu, B. W. Zhu, H. Yang, Y. Q. Liu, B. Li, C. G. Zhan, J. C. Yu,
B.
Liedberg,
X.
D.
Chen,
Adv.
Mater.
27
(2015)
6230-6237.
https://doi.org/10.1002/adma.201503288. [9] Y. B. Wan, Z. G. Qiu, Y. Hong, Y. Wang, J. M. Zhang, Q. X. Liu, Z. G. Wu, C. F. Guo, Adv. Electron. Mater. 4 (2018) 1700586-1700593. https://doi.org/10.1002/aelm.201700586. [10] B. Su, S. Gong, Z. Ma, L. W. Yap, W. L. Cheng, Small 11 (2015) 1886-1891. https://doi.org/10.1002/smll.201403036. [11] S. Kim, T. Y. Eom, M. Cho, K. Y. Song, C. H. An, H. J Lee, B. Hwang, Mater. Lett. 199 (2017) 196-199. https://doi.org/10.1016/j.matlet.2017.04.080. [12] J. Z. Sun, C. H. Yun, B. Cui, P. P. Li, G. P. Liu, X. Wang, F. Q. Chu, Polymers 10 (2018) 1209-1220. https://doi.org/10.3390/polym10111209.
8
Credit Author Statement Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Fuqiang Chu and Jiazhen Sun conceived of and designed the study work. Chenghu Yun acquired and analyzed the data. Bo Cui, Xin Wang and Guangping Liu analyzed and interpreted data. All authors wrote the manuscript and gave final approval for its publication.
9
Graphical Abstract Enhanced Flexibility of Conductive Layer with Inkjet-Imprinted Microstructure Surface Chenghu Yun, Fuqiang Chu,* Bo Cui, Xin Wang, Guangping Liu and Jiazhen Sun* Keyword: microstructure; surface; electrical properties; sensors
Microstructures, such as points, lines and crossed lines, were fabricated based on viscoelastic substrate by inkjet-imprinting. The prepared microstructures could enhance the flexibility of conductive layer on the surface. The results showed that the electrode had a good conductivity and stability during bending. It had a maximum strain which increased to 90%. Therefore, this work provides a facile way for fabricating flexible electrode.
10
Highlights · Microstructures were prepared by a simple method of inkjet-imprinting. · The flexible electrode could withstand 90% strain with the help of microstructure. · Using for monitor knuckle motion, flexible devices exhibited good performance.
11