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Park SJ, Shin J, Magagnosc DJ, Kim S, Cao C, Turner KT, Purohit PK, Gianola DS, Hart AJ. Strong, Ultralight Nanofoams with Extreme Recovery and Dissipation by Manipulation of Internal Adhesive Contacts. ACS NANO 2020; 14:8383-8391. [PMID: 32348120 DOI: 10.1021/acsnano.0c02422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Advances in three-dimensional nanofabrication techniques have enabled the development of lightweight solids, such as hollow nanolattices, having record values of specific stiffness and strength, albeit at low production throughput. At the length scales of the structural elements of these solids-which are often tens of nanometers or smaller-forces required for elastic deformation can be comparable to adhesive forces, rendering the possibility to tailor bulk mechanical properties based on the relative balance of these forces. Herein, we study this interplay via the mechanics of ultralight ceramic-coated carbon nanotube (CNT) structures. We show that ceramic-CNT foams surpass other architected nanomaterials in density-normalized strength and that, when the structures are designed to minimize internal adhesive interactions between CNTs, more than 97% of the strain after compression beyond densification is recovered. Via experiments and modeling, we study the dependence of the recovery and dissipation on the coating thickness, demonstrate that internal adhesive contacts impede recovery, and identify design guidelines for ultralight materials to have maximum recovery. The combination of high recovery and dissipation in ceramic-CNT foams may be useful in structural damping and shock absorption, and the general principles could be broadly applied to both architected and stochastic nanofoams.
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Affiliation(s)
- Sei Jin Park
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Jungho Shin
- Materials Department, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Daniel J Magagnosc
- Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Sanha Kim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Changhong Cao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kevin T Turner
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Prashant K Purohit
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Daniel S Gianola
- Materials Department, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - A John Hart
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Yang X, Chen L, Zhang P, Zhong H, Zhang Y, Zhang R, Gu P, Zhao Y. Investigation of the relationship between adhesion force and mechanical behavior of vertically aligned carbon nanotube arrays. NANOTECHNOLOGY 2020; 31:295701. [PMID: 32240994 DOI: 10.1088/1361-6528/ab85ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The mechanical behavior of vertically aligned carbon nanotube (VACNT) arrays can largely impact their adhesion performance. In this paper, we fabricated various VACNT arrays to investigate the relationship between adhesion force and their mechanical behavior. High-volume fraction (3.4%) CNT arrays did not exhibit the applicable adhesion effect due to their intrinsic elastic property. Adhesion measurements on several low-density (less than 0.5%) VACNT arrays demonstrated that the adhesion performance is strongly related to the plastic deformation of the carbon nanotubes at the contact surface. Due to the nature of the growth of CNT arrays, the top region of the as-grown CNT arrays is denser and stiffer than the bottom region of the arrays. Therefore, compared with as-grown CNT arrays, the flipped CNT arrays reached higher adhesion efficiency (the ratio of adhesion force to preload) with lower preload due to the higher compliance at the top surface of the arrays. With cyclic loading under micro mechanical tests, stiffening of the surface and declining of adhesion force were also observed. These results illustrated that the mechanical compliance at the region near the contact interface is the dominant factor for the adhesion performance of VACNT arrays.
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Affiliation(s)
- Xiaochen Yang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230022, People's Republic of China. Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230022, People's Republic of China
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Pei Y, Zhong H, Wang M, Zhang P, Zhao Y. Effect of Contact Pressure on the Performance of Carbon Nanotube Arrays Thermal Interface Material. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E732. [PMID: 30227621 PMCID: PMC6163777 DOI: 10.3390/nano8090732] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/12/2018] [Accepted: 09/13/2018] [Indexed: 11/16/2022]
Abstract
Vertically aligned carbon nanotube (CNT) arrays are promising candidates for advanced thermal interface materials (TIMs) since they possess high mechanical compliance and high intrinsic thermal conductivity. Some of the previous works indicate that the CNT arrays in direct dry contact with the target surface possess low contact thermal conductance, which is the dominant thermal resistance. Using a phase sensitive transient thermo-reflectance (PSTTR) technique, we measure the thermal conductance between CNT arrays and copper (Cu) surfaces under different pressures. The experiments demonstrated that the contact force is one of the crucial factors for optimizing the thermal performance of CNT array-based TIMs. The experimental results suggest that the Cu-CNT arrays' contact thermal conductance has a strong dependence on the surface deformation and has an order of magnitude rise as the contact pressure increases from 0.05 to 0.15 MPa. However, further increase of the contact pressure beyond 0.15 MPa has little effect on the contact thermal resistance. This work could provide guidelines to determine the minimum requirement of packaging pressure on CNT TIMs.
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Affiliation(s)
- Yu Pei
- Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei 230022, China.
- CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD), Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
| | - Hongmei Zhong
- Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei 230022, China.
- CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD), Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
| | - Mengyu Wang
- Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei 230022, China.
- CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD), Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
| | - Peng Zhang
- Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei 230022, China.
- CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD), Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
| | - Yang Zhao
- Department of Precision Machinery & Precision Instrumentation, University of Science and Technology of China, Hefei 230022, China.
- CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD), Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
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Jing L, Li H, Lin J, Tay RY, Tsang SH, Teo EHT, Tok AIY. Supercompressible Coaxial Carbon Nanotube@Graphene Arrays with Invariant Viscoelasticity over -100 to 500 °C in Ambient Air. ACS APPLIED MATERIALS & INTERFACES 2018; 10:9688-9695. [PMID: 29489328 DOI: 10.1021/acsami.8b01925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Vertically aligned carbon nanotube (CNT) arrays have been recognized as promising cushion materials because of their superior thermal stability, remarkable compressibility, and viscoelastic characteristics. However, most of the previously reported CNT arrays still suffer from permanent shape deformation at only moderate compressive strains, which considerably restricts their practical applications. Here, we demonstrate a facile strategy of fabricating supercompressible coaxial CNT@graphene (CNT@Gr) arrays by using a two-step route involving encapsulating polymer layers onto plastic CNT arrays and subsequent annealing processes. Notably, the resulting CNT@Gr arrays are able to almost completely recover from compression at a strain of up to 80% and retain ∼80% recovery even after 1000 compression cycles at a 60% strain, demonstrating their excellent compressibility. Furthermore, they possess outstanding strain- and frequency-dependent viscoelastic responses, with storage modulus and damping ratio of up to ∼6.5 MPa and ∼0.19, respectively, which are nearly constant over an exceptionally broad temperature range of -100 to 500 °C in ambient air. These supercompressibility and temperature-invariant viscoelasticity together with facile fabrication process of the CNT@Gr arrays enable their promising multifunctional applications such as energy absorbers, mechanical sensors, and heat exchangers, even in extreme environments.
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Affiliation(s)
| | | | | | | | - Siu Hon Tsang
- Temasek Laboratories@NTU , 50 Nanyang Avenue , Singapore 639798 , Singapore
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Li Y, Kang J, Choi JB, Nam JD, Suhr J. Determination of material constants of vertically aligned carbon nanotube structures in compressions. NANOTECHNOLOGY 2015; 26:245701. [PMID: 26011574 DOI: 10.1088/0957-4484/26/24/245701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Different chemical vapour deposition (CVD) fabrication conditions lead to a wide range of variation in the microstructure and morphologies of carbon nanotubes (CNTs), which actually determine the compressive mechanical properties of CNTs. However, the underlying relationship between the structure/morphology and mechanical properties of CNTs is not fully understood. In this study, we characterized and compared the structural and morphological properties of three kinds of vertically aligned carbon nanotube (VACNT) arrays from different CVD fabrication methods and performed monotonic compressive tests for each VACNT array. The compressive stress-strain responses and plastic deformation were first compared and analyzed with nanotube buckling behaviours. To quantify the compressive properties of the VACNT arrays, a strain density energy function was used to determine their intrinsic material constants. Then, the structural and morphological effects on the quantified material constants of the VACNTs were statistically investigated and analogized to cellular materials with an open-cell model. The statistical analysis shows that density, defect degree, and the moment of inertia of the CNTs are key factors in the improvement of the compressive mechanical properties of VACNT arrays. This approach could allow a model-driven CNT synthesis for engineering their mechanical behaviours.
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Affiliation(s)
- Yupeng Li
- Department of Mechanical Engineering, University of Delaware, Newark, DE, 19711, USA
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Lin Z, Gui X, Gan Q, Chen W, Cheng X, Liu M, Zhu Y, Yang Y, Cao A, Tang Z. In-Situ Welding Carbon Nanotubes into a Porous Solid with Super-High Compressive Strength and Fatigue Resistance. Sci Rep 2015; 5:11336. [PMID: 26067176 PMCID: PMC4464184 DOI: 10.1038/srep11336] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 05/22/2015] [Indexed: 11/29/2022] Open
Abstract
Carbon nanotube (CNT) and graphene-based sponges and aerogels have an isotropic porous structure and their mechanical strength and stability are relatively lower. Here, we present a junction-welding approach to fabricate porous CNT solids in which all CNTs are coated and welded in situ by an amorphous carbon layer, forming an integral three-dimensional scaffold with fixed joints. The resulting CNT solids are robust, yet still highly porous and compressible, with compressive strengths up to 72 MPa, flexural strengths up to 33 MPa, and fatigue resistance (recovery after 100,000 large-strain compression cycles at high frequency). Significant enhancement of mechanical properties is attributed to the welding-induced interconnection and reinforcement of structural units, and synergistic effects stemming from the core-shell microstructures consisting of a flexible CNT framework and a rigid amorphous carbon shell. Our results provide a simple and effective method to manufacture high-strength porous materials by nanoscale welding.
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Affiliation(s)
- Zhiqiang Lin
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Xuchun Gui
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Qiming Gan
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Wenjun Chen
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Xiaoping Cheng
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Ming Liu
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Yuan Zhu
- State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Yanbing Yang
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, P. R. China
| | - Anyuan Cao
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, P. R. China
| | - Zikang Tang
- 1] State Key Lab of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China [2] Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Copic D, Hart AJ. Corrugated paraffin nanocomposite films as large stroke thermal actuators and self-activating thermal interfaces. ACS APPLIED MATERIALS & INTERFACES 2015; 7:8218-8224. [PMID: 25822633 DOI: 10.1021/acsami.5b01141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
High performance active materials are of rapidly growing interest for applications including soft robotics, microfluidic systems, and morphing composites. In particular, paraffin wax has been used to actuate miniature pumps, solenoid valves, and composite fibers, yet its deployment is typically limited by the need for external volume constraint. We demonstrate that compact, high-performance paraffin actuators can be made by confining paraffin within vertically aligned carbon nanotube (CNT) films. This large-stroke vertical actuation is enabled by strong capillary interaction between paraffin and CNTs and by engineering the CNT morphology by mechanical compression before capillary-driven infiltration of the molten paraffin. The maximum actuation strain of the corrugated CNT-paraffin films (∼0.02-0.2) is comparable to natural muscle, yet the maximum stress is limited to ∼10 kPa by collapse of the CNT network. We also show how a CNT-paraffin film can serve as a self-activating thermal interface that closes a gap when it is heated. These new CNT-paraffin film actuators could be produced by large-area CNT growth, infiltration, and lamination methods, and are attractive for use in miniature systems due to their self-contained design.
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Affiliation(s)
- Davor Copic
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, Michigan 48109, United States
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, Michigan 48109, United States
| | - A John Hart
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, Michigan 48109, United States
- Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, Michigan 48109, United States
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Zeng Z, Gui X, Gan Q, Lin Z, Zhu Y, Zhang W, Xiang R, Cao A, Tang Z. Integrated random-aligned carbon nanotube layers: deformation mechanism under compression. NANOSCALE 2014; 6:1748-1755. [PMID: 24352698 DOI: 10.1039/c3nr04667b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Carbon nanotubes have the potential to construct highly compressible and elastic macroscopic structures such as films, aerogels and sponges. The structure-related deformation mechanism determines the mechanical behavior of those structures and niche applications. Here, we show a novel strategy to integrate aligned and random nanotube layers and reveal their deformation mechanism under uniaxial compression with a large range of strain and cyclic testing. Integrated nanotube layers deform sequentially with different mechanisms due to the distinct morphology of each layer. While the aligned layer forms buckles under compression, nanotubes in the random layer tend to be parallel and form bundles, resulting in the integration of quite different properties (strength and stiffness) and correspondingly distinct plateau regions in the stress-strain curves. Our results indicate a great promise of constructing hierarchical carbon nanotube structures with tailored energy absorption properties, for applications such as cushioning and buffering layers in microelectromechanical systems.
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Affiliation(s)
- Zhiping Zeng
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China.
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