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Chen X, Cui J, Liu Z, Wang Y, Li M, Zhang J, Pan S, Wang M, Bao C, Wei Q. Polyacrylamide/sodium alginate/sodium chloride photochromic hydrogel with high conductivity, anti-freezing property and fast response for information storage and electronic skin. Int J Biol Macromol 2024; 268:131972. [PMID: 38697436 DOI: 10.1016/j.ijbiomac.2024.131972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/07/2024] [Accepted: 04/28/2024] [Indexed: 05/05/2024]
Abstract
Photochromic hydrogels have promising prospects in areas such as wearable device, information encryption technology, optoelectronic display technology, and electronic skin. However, there are strict requirements for the properties of photochromic hydrogels in practical engineering applications, especially in some extreme application environments. The preparation of photochromic hydrogels with high transparency, high toughness, fast response, colour reversibility, excellent electrical conductivity, and anti-freezing property remains a challenge. In this study, a novel photochromic hydrogel (PAAm/SA/NaCl-Mo7) was prepared by loading ammonium molybdate (Mo7) and sodium chloride (NaCl) into a dual-network hydrogel of polyacrylamide (PAAm) and sodium alginate (SA) using a simple one-pot method. PAAm/SA/NaCl-Mo7 hydrogel has excellent conductivity (175.9 S/cm), water retention capacity and anti-freezing properties, which can work normally at a low temperature of -28.4 °C. In addition, the prepared PAAm/SA/NaCl-Mo7 hydrogel exhibits fast response (<15 s), high transparency (>70 %), good toughness (maximum elongation up to 1500 %), good cyclic compression properties at high compressive strains (60 %), good biocompatibility (78.5 %), stable reversible discolouration and excellent sensing properties, which can be used for photoelectric display, information storage and motion monitoring. This work provides a new inspiration for the development of flexible electronic skin devices.
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Affiliation(s)
- Xiaohu Chen
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Jiashu Cui
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Zhisheng Liu
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Yanen Wang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China.
| | - Mingyang Li
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Juan Zhang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Siyu Pan
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Mengjie Wang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Chengwei Bao
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China
| | - Qinghua Wei
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China; Bio-additive manufacturing university-enterprise joint research center of Shaanxi Province, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, PR China.
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Zheng J, Yu H, Zhang Y, Wang J, Guo H, Luo H, Wang X, Qiu Y, Liu L, Li WJ. 4D Printed Soft Microactuator for Particle Manipulation via Surrounding Medium Variation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2311951. [PMID: 38593355 DOI: 10.1002/smll.202311951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/20/2024] [Indexed: 04/11/2024]
Abstract
Soft actuators have assumed vital roles in a diverse number of research and application fields, driving innovation and transformative advancements. Using 3D molding of smart materials and combining these materials through structural design strategies, a single soft actuator can achieve multiple functions. However, it is still challenging to realize soft actuators that possess high environmental adaptability while capable of different tasks. Here, the response threshold of a soft actuator is modulated by precisely tuning the ratio of stimulus-responsive groups in hydrogels. By combining a heterogeneous bilayer membrane structure and in situ multimaterial printing, the obtained soft actuator deformed in response to changes in the surrounding medium. The response medium is suitable for both biotic and abiotic environments, and the response rate is fast. By changing the surrounding medium, the precise capture, manipulation, and release of micron-sized particles of different diameters in 3D are realized. In addition, static capture of a single red blood cell is realized using biologically responsive medium changes. Finally, the experimental results are well predicted using finite element analysis. It is believed that with further optimization of the structure size and autonomous navigation platform, the proposed soft microactuator has significant potential to function as an easy-to-manipulate multifunctional robot.
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Affiliation(s)
- Jianchen Zheng
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haibo Yu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
| | - Yuzhao Zhang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jingang Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongji Guo
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
| | - Hao Luo
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoduo Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
| | - Ye Qiu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
| | - Wen Jung Li
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110169, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
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Das S, Thimukonda Jegadeesan J, Basu B. Advancing Peripheral Nerve Regeneration: 3D Bioprinting of GelMA-Based Cell-Laden Electroactive Bioinks for Nerve Conduits. ACS Biomater Sci Eng 2024; 10:1620-1645. [PMID: 38345020 DOI: 10.1021/acsbiomaterials.3c01226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Peripheral nerve injuries often result in substantial impairment of the neurostimulatory organs. While the autograft is still largely used as the "gold standard" clinical treatment option, nerve guidance conduits (NGCs) are currently considered a promising approach for promoting peripheral nerve regeneration. While several attempts have been made to construct NGCs using various biomaterial combinations, a comprehensive exploration of the process science associated with three-dimensional (3D) extrusion printing of NGCs with clinically relevant sizes (length: 20 mm; diameter: 2-8 mm), while focusing on tunable buildability using electroactive biomaterial inks, remains unexplored. In addressing this gap, we present here the results of the viscoelastic properties of a range of a multifunctional gelatin methacrylate (GelMA)/poly(ethylene glycol) diacrylate (PEGDA)/carbon nanofiber (CNF)/gellan gum (GG) hydrogel bioink formulations and printability assessment using experiments and quantitative models. Our results clearly established the positive impact of the gellan gum on the enhancement of the rheological properties. Interestingly, the strategic incorporation of PEGDA as a secondary cross-linker led to a remarkable enhancement in the strength and modulus by 3 and 8-fold, respectively. Moreover, conductive CNF addition resulted in a 4-fold improvement in measured electrical conductivity. The use of four-component electroactive biomaterial ink allowed us to obtain high neural cell viability in 3D bioprinted constructs. While the conventionally cast scaffolds can support the differentiation of neuro-2a cells, the most important result has been the excellent cell viability of neural cells in 3D encapsulated structures. Taken together, our findings demonstrate the potential of 3D bioprinting and multimodal biophysical cues in developing functional yet critical-sized nerve conduits for peripheral nerve tissue regeneration.
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Affiliation(s)
- Soumitra Das
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | | | - Bikramjit Basu
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
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Aazmi A, Zhang D, Mazzaglia C, Yu M, Wang Z, Yang H, Huang YYS, Ma L. Biofabrication methods for reconstructing extracellular matrix mimetics. Bioact Mater 2024; 31:475-496. [PMID: 37719085 PMCID: PMC10500422 DOI: 10.1016/j.bioactmat.2023.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/19/2023] Open
Abstract
In the human body, almost all cells interact with extracellular matrices (ECMs), which have tissue and organ-specific compositions and architectures. These ECMs not only function as cellular scaffolds, providing structural support, but also play a crucial role in dynamically regulating various cellular functions. This comprehensive review delves into the examination of biofabrication strategies used to develop bioactive materials that accurately mimic one or more biophysical and biochemical properties of ECMs. We discuss the potential integration of these ECM-mimics into a range of physiological and pathological in vitro models, enhancing our understanding of cellular behavior and tissue organization. Lastly, we propose future research directions for ECM-mimics in the context of tissue engineering and organ-on-a-chip applications, offering potential advancements in therapeutic approaches and improved patient outcomes.
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Affiliation(s)
- Abdellah Aazmi
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, 310058, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Duo Zhang
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
- School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, 51817, China
| | - Corrado Mazzaglia
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Mengfei Yu
- The Affiliated Stomatologic Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Zhen Wang
- Center for Laboratory Medicine, Allergy Center, Department of Transfusion Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang, 310014, China
| | - Huayong Yang
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, 310058, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Yan Yan Shery Huang
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Liang Ma
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, 310058, China
- School of Mechanical Engineering, Zhejiang University, Hangzhou, 310058, China
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Sun S, Li H, Zhang M, Sun B, Xie Y, Zhou W, Yang P, Mi HY, Guo Z, Liu C, Shen C. A Multifunctional Asymmetric Fabric for Sustained Electricity Generation from Multiple Sources and Simultaneous Solar Steam Generation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303716. [PMID: 37475506 DOI: 10.1002/smll.202303716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/30/2023] [Indexed: 07/22/2023]
Abstract
Harvesting electrical energy from water and moisture has emerged as a novel ecofriendly energy conversion technology. Herein, a multifunctional asymmetric polyaniline/carbon nanotubes/poly(vinyl alcohol) (APCP) that can produce electric energy from both saline water and moisture and generate fresh water simultaneously is developed. The constructed APCP possesses a negatively charged porous structure that allows continuous generation of protons and ion diffusion through the material, and a hydrophilicity-hydrophobic interface which results in a constant potential difference and sustainable output. A single APCP can maintain stable output for over 130 h and preserve a high voltage of 0.61 V, current of 81 µA, and power density of 82.4 µW cm-3 with 0.15 cm3 unit size in the water-induced electricity generation process. When harvesting moisture energy, the APCP creates dry-wet asymmetries and triggers the spontaneous development of electrical double layer with a current density of 1.25 mA cm-3 , sufficient to power small electronics. A device consisting of four APCP can generate stable electricity of 3.35 V and produce clean water with an evaporation rate of 2.06 kg m-2 h-1 simultaneously. This work provides insights into the fabrication of multifunctional fabrics for multisource energy harvesting and simultaneous solar steam generation.
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Affiliation(s)
- Shuangjie Sun
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Hui Li
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Miaomiao Zhang
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Binbin Sun
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Yibing Xie
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Wei Zhou
- Department of Mechanical Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Peipei Yang
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Hao-Yang Mi
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Zhanhu Guo
- Department of Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Chuntai Liu
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
| | - Changyu Shen
- National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Advanced Materials Processing & Mold of Ministry of Education, Zhengzhou University, Zhengzhou, 450001, P. R. China
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Chen X, Zhang H, Cui J, Wang Y, Li M, Zhang J, Wang C, Liu Z, Wei Q. Enhancing Conductivity and Self-Healing Properties of PVA/GEL/OSA Composite Hydrogels by GO/SWNTs for Electronic Skin. Gels 2023; 9:gels9020155. [PMID: 36826325 PMCID: PMC9956163 DOI: 10.3390/gels9020155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
The use of flexible, self-healing conductive hydrogels as a type of typical electronic skin with the function of transmitting sensory signals has attracted wide attention in the field of biomaterials. In this study, composite hydrogels based on polyvinyl alcohol (PVA), gelatin (GEL), oxidized sodium alginate (OSA), graphene oxide (GO), and single-walled carbon nanotubes (SWNTs) were successfully prepared. The hydrogen and imine bonding of the composite hydrogels gives them excellent self-healing properties. Their self-healing properties restore 68% of their breaking strength and over 95% of their electrical conductivity. The addition of GO and SWNTs enables the PGO-GS hydrogels to achieve a compressive modulus and conductivity of 42.2 kPa and 29.6 mS/m, which is 8.2 times and 1.5 times that of pure PGO, respectively. Furthermore, the PGO-GS hydrogels can produce profound feedback signals in response to deformation caused by external forces and human movements such as finger flexion and speech. In addition, the PGO-GS hydrogels exhibit superior biocompatibility compared to PGO. All of these results indicate that the PGO-GS hydrogels have great potential with respect to future applications in the field of electronic skin.
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Affiliation(s)
- Xiaohu Chen
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Haonan Zhang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Jiashu Cui
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Yanen Wang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
- Correspondence: (Y.W.); (Q.W.); Tel./Fax: +86-029-88493232 (Y.W.)
| | - Mingyang Li
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Juan Zhang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Changgeng Wang
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Zhisheng Liu
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
| | - Qinghua Wei
- Department of Indurstry and Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
- Bio-Additive Manufacturing University-Enterprise Joint Research Center of Shaanxi Province, Northwestern Polytechnical University, Xi’an 710072, China
- Correspondence: (Y.W.); (Q.W.); Tel./Fax: +86-029-88493232 (Y.W.)
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Hong Y, Lin Z, Yang Y, Jiang T, Shang J, Luo Z. Flexible Actuator Based on Conductive PAM Hydrogel Electrodes with Enhanced Water Retention Capacity and Conductivity. MICROMACHINES 2022; 13:1951. [PMID: 36422380 PMCID: PMC9695116 DOI: 10.3390/mi13111951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 10/28/2022] [Accepted: 11/10/2022] [Indexed: 06/16/2023]
Abstract
Conductive polyacrylamide (PAM) hydrogels with salts that act as electrolytes have been used as transparent electrodes with high elasticity in flexible electronic devices. Different types and contents of raw materials will affect their performance in all aspects. We tried to introduce highly hydratable salts into PAM hydrogels to improve their water retention capacity. Different salts can improve the water retention capacity of PAM hydrogels to a certain extent. In particular, PAM hydrogels containing higher concentrations of lithium chloride (LiCl) and calcium chloride (CaCl2) showed an extremely strong water retention capacity and could retain about 90% and more than 98% of the initial water in the experimental environment at a temperature of 25 °C and a relative humidity of 60% RH, respectively. In addition, we conducted electrical conductivity tests on these PAM hydrogels with different salts. The PAM hydrogels containing LiCl also show outstanding conductivity, and the highest conductivity value can reach up to about 8 S/m. However, the PAM hydrogels containing CaCl2, which also performed well in terms of their water retention capacity, were relatively common in terms of their electrical conductivity. On this basis, we attempted to introduce single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and graphene (GO) electronic conductors to enhance the electrical conductivity of the PAM hydrogels containing LiCl. The conductivity of the PAM hydrogels containing LiCl was improved to a certain extent after the addition of these electronic conductors. The highest electrical conductivity was about 10 S/m after we added the SWCNTs. This experimental result indicates that these electronic conductors can indeed enhance the electrical conductivity of PAM hydrogels to a certain extent. After a maximum of 5000 repeated tensile tests, the conductive hydrogel samples could still maintain their original morphological characteristics and conductivity. This means that these conductive hydrogel samples have a certain degree of system reliability. We made the PAM conductive hydrogels with high water retention and good conductivity properties into thin electrodes and applied them to an electric response flexible actuator with dielectric elastomer as the functional material. This flexible actuator can achieve a maximum area strain of 18% under an external voltage of 10 kV. This new composite hydrogels with high water retention and excellent conductivity properties will enable more possibilities for the application of hydrogels.
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