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Carvalho AF, Kulyk B, Fernandes AJS, Fortunato E, Costa FM. A Review on the Applications of Graphene in Mechanical Transduction. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2101326. [PMID: 34288155 DOI: 10.1002/adma.202101326] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/26/2021] [Indexed: 05/26/2023]
Abstract
A pressing need to develop low-cost, environmentally friendly, and sensitive sensors has arisen with the advent of the always-connected paradigm of the internet-of-things (IoT). In particular, mechanical sensors have been widely studied in recent years for applications ranging from health monitoring, through mechanical biosignals, to structure integrity analysis. On the other hand, innovative ways to implement mechanical actuation have also been the focus of intense research in an attempt to close the circle of human-machine interaction, and move toward applications in flexible electronics. Due to its potential scalability, disposability, and outstanding properties, graphene has been thoroughly studied in the field of mechanical transduction. The applications of graphene in mechanical transduction are reviewed here. An overview of sensor and actuator applications is provided, covering different transduction mechanisms such as piezoresistivity, capacitive sensing, optically interrogated displacement, piezoelectricity, triboelectricity, electrostatic actuation, chemomechanical and thermomechanical actuation, as well as thermoacoustic emission. A critical review of the main approaches is presented within the scope of a wider discussion on the future of this so-called wonder material in the field of mechanical transduction.
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Affiliation(s)
- Alexandre F Carvalho
- I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro, 3810-193, Portugal
| | - Bohdan Kulyk
- I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro, 3810-193, Portugal
| | | | - Elvira Fortunato
- I3N/CENIMAT, Materials Science Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Caparica, 2829-516, Portugal
| | - Florinda M Costa
- I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro, 3810-193, Portugal
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Abstract
Electro-responsive actuators (ERAs) hold great promise for cutting-edge applications in e-skins, soft robots, unmanned flight, and in vivo surgery devices due to the advantages of fast response, precise control, programmable deformation, and the ease of integration with control circuits. Recently, considering the excellent physical/chemical/mechanical properties (e.g., high carrier mobility, strong mechanical strength, outstanding thermal conductivity, high specific surface area, flexibility, and transparency), graphene and its derivatives have emerged as an appealing material in developing ERAs. In this review, we have summarized the recent advances in graphene-based ERAs. Typical the working mechanisms of graphene ERAs have been introduced. Design principles and working performance of three typical types of graphene ERAs (e.g., electrostatic actuators, electrothermal actuators, and ionic actuators) have been comprehensively summarized. Besides, emerging applications of graphene ERAs, including artificial muscles, bionic robots, human-soft actuators interaction, and other smart devices, have been reviewed. At last, the current challenges and future perspectives of graphene ERAs are discussed.
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Kumar V, Alam MN, Manikkavel A, Song M, Lee DJ, Park SS. Silicone Rubber Composites Reinforced by Carbon Nanofillers and Their Hybrids for Various Applications: A Review. Polymers (Basel) 2021; 13:polym13142322. [PMID: 34301079 PMCID: PMC8309633 DOI: 10.3390/polym13142322] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/07/2021] [Accepted: 07/12/2021] [Indexed: 02/06/2023] Open
Abstract
Without fillers, rubber types such as silicone rubber exhibit poor mechanical, thermal, and electrical properties. Carbon black (CB) is traditionally used as a filler in the rubber matrix to improve its properties, but a high content (nearly 60 per hundred parts of rubber (phr)) is required. However, this high content of CB often alters the viscoelastic properties of the rubber composite. Thus, nowadays, nanofillers such as graphene (GE) and carbon nanotubes (CNTs) are used, which provide significant improvements to the properties of composites at as low as 2–3 phr. Nanofillers are classified as those fillers consisting of at least one dimension below 100 nanometers (nm). In the present review paper, nanofillers based on carbon nanomaterials such as GE, CNT, and CB are explored in terms of how they improve the properties of rubber composites. These nanofillers can significantly improve the properties of silicone rubber (SR) nanocomposites and have been useful for a wide range of applications, such as strain sensing. Therefore, carbon-nanofiller-reinforced SRs are reviewed here, along with advancements in this research area. The microstructures, defect densities, and crystal structures of different carbon nanofillers for SR nanocomposites are characterized, and their processing and dispersion are described. The dispersion of the rubber composites was reported through atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The effect of these nanofillers on the mechanical (compressive modulus, tensile strength, fracture strain, Young’s modulus, glass transition), thermal (thermal conductivity), and electrical properties (electrical conductivity) of SR nanocomposites is also discussed. Finally, the application of the improved SR nanocomposites as strain sensors according to their filler structure and concentration is discussed. This detailed review clearly shows the dependency of SR nanocomposite properties on the characteristics of the carbon nanofillers.
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Affiliation(s)
- Vineet Kumar
- School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Korea; (V.K.); (M.N.A.); (A.M.); (D.-J.L.)
| | - Md Najib Alam
- School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Korea; (V.K.); (M.N.A.); (A.M.); (D.-J.L.)
| | - Amutheesan Manikkavel
- School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Korea; (V.K.); (M.N.A.); (A.M.); (D.-J.L.)
| | - Minseok Song
- Graduate School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Korea;
| | - Dong-Joo Lee
- School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Korea; (V.K.); (M.N.A.); (A.M.); (D.-J.L.)
| | - Sang-Shin Park
- School of Mechanical Engineering, Yeungnam University, 280, Daehak-ro, Gyeongsan 38541, Korea; (V.K.); (M.N.A.); (A.M.); (D.-J.L.)
- Correspondence:
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Joshi S, Kaushik BK. Transition metal dichalcogenides integrated waveguide modulator and attenuator in silicon nitride platform. NANOTECHNOLOGY 2020; 31:435202. [PMID: 32659747 DOI: 10.1088/1361-6528/aba579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Embedding transition metal dichalcogenides (TMDs) into optical devices enhance the light-matter interaction, which holds a great promise for designing compact integrated photonic components. The chemical composition and thickness of TMDs affect their electronic and optical properties. The optical properties demonstrate stable and strong gate tunable optical response near the excitonic transitions. These materials are, therefore, promising candidates for designing electro-optic modulators and attenuators. Here, an electro-absorption modulator is investigated based on integrating different TMD monolayers on silicon nitride waveguides near the excitonic binding energy. A comparison of absorption changes due to electrostatically induced charges in MoS2, MoSe2, WS2, WSe2, and graphene has been presented for modulator design. The results show that with the confinement factor of about 0.10% in the monolayer TMDs, the modulation strength is 10x higher in WS2 as compared to the graphene-based modulator design. The WS2 based modulator shows the highest modulation strength with an improvement by a factor of 5 as compared to Mo based designs. Further, the change in the spectral response of these materials with thickness and chemical composition has been exploited for the design of attenuator. A micro-opto-mechanical system technology with TMD integrated supersubstrate above a Si3N4 waveguide affecting the optical response is investigated. By replacing the TMD in the supersubstrate with Se atom instead of S in the MX2 and WX2 compound, the attenuation is shifted from visible to near-infrared range allowing tuning from 620 to 750 nm. The tuning of the attenuation wavelength will help the designer choose the best material for visible light photonic applications.
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Affiliation(s)
- Swati Joshi
- Microelectronics and VLSI Group, Department of Electronics and Communication Engineering, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
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Optimized CNT-PDMS Flexible Composite for Attachable Health-Care Device. SENSORS 2020; 20:s20164523. [PMID: 32823502 PMCID: PMC7472186 DOI: 10.3390/s20164523] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/31/2020] [Accepted: 08/07/2020] [Indexed: 01/21/2023]
Abstract
The CNT-PDMS composite has been widely adopted in flexible devices due to its high elasticity, piezoresistivity, and biocompatibility. In a wide range of applications, CNT-PDMS composite sensors were used for resistive strain measurement. Accordingly, the percolation threshold 2%~4% of the CNT weight ratio in the CNT-PDMS composite was commonly selected, which is expected to achieve the optimized piezoresistive sensitivity. However, the linear range around the percolation threshold weight ratio (2%~4%) limits its application in a stable output of large strain (>20%). Therefore, comprehensive understanding of the electromechanical, mechanical, and electrical properties for the CNT-PDMS composite with different CNT weight ratios was expected. In this paper, a systematic study was conducted on the piezoresistivity, Young’s modulus, conductivity, impedance, and the cross-section morphology of different CNT weight ratios (1 to 10 wt%) of the CNT-PDMS composite material. It was experimentally observed that the piezo-resistive sensitivity of CNT-PDMS negatively correlated with the increase in the CNT weight ratio. However, the electrical conductivity, Young’s modulus, tensile strength, and the linear range of piezoresistive response of the CNT-PDMS composite positively correlated with the increase in CNT weight ratio. Furthermore, the mechanism of these phenomena was analyzed through the cross-section morphology of the CNT-PDMS composite material by using SEM imaging. From this analysis, a guideline was proposed for large strain (40%) measurement applications (e.g., motion monitoring of the human body of the finger, arm, foot, etc.), the CNT weight ratio 8 wt% was suggested to achieve the best piezoresistive sensitivity in the linear range.
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Wei L, Wang JW, Gao XH, Wang HQ, Wang XZ, Ren H. Enhanced Dielectric Properties of a Poly(dimethyl siloxane) Bimodal Network Percolative Composite with MXene. ACS APPLIED MATERIALS & INTERFACES 2020; 12:16805-16814. [PMID: 32186174 DOI: 10.1021/acsami.0c01409] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Excellent comprehensive dielectric properties (including dielectric constant and loss) are essential for electromechanical transducers. This work introduced a bimodal network composite with poly(dimethyl siloxane) (PDMS) and delaminated Ti3C2Tx sheets (d-Ti3C2Tx) modified with hyperbranched polysiloxane (HPSi) (referred to as HPSi-d-Ti3C2Tx). Before the final cross-linking, HPSi-d-Ti3C2Tx, trapped with short-chain PDMS (CS-PDMS) and long-chain PDMS (CL-PDMS), was pre-reacted, which formed a distinct bimodal network structure. d-Ti3C2Tx/PDMS and HPSi-d-Ti3C2Tx/PDMS composites with different filler loadings were prepared, and their percolation thresholds (fc) were 1.32 and 1.43 vol %, respectively The dielectric constant of 1.40 vol % HPSi-d-Ti3C2Tx/PDMS is 23.7 at 102 Hz, which is 1.5 times that of 1.28 vol % d-Ti3C2Tx/PDMS and 8.5 times that of pure PDMS. Meanwhile, the dielectric loss of HPSi-d-Ti3C2Tx/PDMS composite is still relatively small (0.11 at 103 Hz). The origin of dielectric property optimization of the composite is attributed to the boundary capacitor model, the accumulated charges at the interfaces between the conductive filler and the insulating polymer matrix of the composite, and the distinct bimodal network structure.
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Affiliation(s)
- Lei Wei
- Department of Materials Science and Engineering, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P. R. China
| | - Jing-Wen Wang
- College of Materials Science and Technology, Nanjing University of Aeronautics & Astronautics, 29 Yudao Street, Nanjing 210016, P. R. China
| | - Xin-Hua Gao
- Department of Materials Science and Engineering, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P. R. China
| | - Hou-Qing Wang
- Department of Materials Science and Engineering, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P. R. China
| | - Xin-Zhu Wang
- Department of Materials Science and Engineering, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, P. R. China
| | - Hua Ren
- Department of Materials Science and Engineering, Nanjing University, 22 Hankou Road, Nanjing 210093, P. R. China
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