Effective Young's modulus of carbon nanofiber array

2006 ◽  
Vol 21 (11) ◽  
pp. 2948-2954 ◽  
Author(s):  
Yi Zhang ◽  
Ephraim Suhir ◽  
Yuan Xu
Keyword(s):  
Young’S Modulus ◽  
Carbon Nanofibers ◽  
Carbon Nanofiber ◽  
Young's Modulus ◽  
Compressive Load ◽  
Nonlinear Behavior ◽  
Chemical Vapor ◽  
Wall Structure ◽  
Structural Element ◽  
Multiwalled Carbon

We developed a methodology for the evaluation of the effective Young's modulus (EYM) of the vertically aligned carbon nanofibers array (CNFA). The carbon nanofibers array is treated in this study as a continuous structural element, and, for this reason, the determined EYM might be appreciably different (actually, lower) than the Young's modulus (YM) of the material of an individual carbon nanotube or a nanofiber. The developed methodology is based on the application of a compressive load onto the carbon nanofibers array, so that each individual carbon nanofiber experiences axial compression and is expected to buckle under the compressive load. The relationship between the applied compressive stress and the induced displacement of the carbon nanofiber array is measured using a table version of an Instron tester. It has been found that the carbon nanofiber array exhibits nonlinear behavior and the EYM increases with an increase in the compressive load. The largest measured EYM of the carbon nanofiber array turned out to be about 90 GPa. It has been found also that the fragmentary pieces of lateral graphitic layer in the carbon nanofiber array resulted in substantial worsening of the quality of the carbon nanofibers. This might be one of the possible reasons why the measured EYM turned out to be much lower than the theoretical predictions reported in the literature. The measured EYM is also much lower than the reported in the literature atomic force microscopy (AFM)-based data for the EYM for multiwalled carbon nanotubes (MWCNTs) that possess uniform and straight graphitic wall structure. Our transmission electron microscope (TEM) observations have revealed indeed poor structural qualities of the plasma-enhanced chemical vapor deposition (PECVD) grown CNFs.

scholarly journals Role of Carbon Nanofiber on the Electrical Resistivity of Mortar under Compressive Load

2020 ◽  
pp. 036119812094741
Author(s):  
Thanyarat Buasiri ◽  
Karin Habermehl-Cwirzen ◽  
Lukasz Krzeminski ◽  
Andrzej Cwirzen
Keyword(s):  
Electrical Resistivity ◽  
Portland Cement ◽  
Carbon Nanofibers ◽  
Ordinary Portland Cement ◽  
Carbon Nanofiber ◽  
Compressive Load ◽  
Chemical Vapor ◽  
Load Sensing

A nanomodified cement consisting of particles with in situ synthesized carbon nanofibers was developed to introduce a strong load-sensing capability of the hydrated binder matrix. The material was produced using chemical vapor deposition. The nanomodified cement contained 2.71 wt% of carbon nanofibers (CNFs). The electrical properties of the composite were determined. Several mortar samples were prepared by partially substituting ordinary Portland cement with 2, 4, 6, 8, and 10 wt% of the nanomodified cement. Additionally an ordinary Portland cement mortar was used as reference. The results show that the strongest piezoresistive response and therefore the best load-sensing was obtained for the mortar containing the highest amount of CNFs. This mortar contained 10 wt% of nanomodified cement. The fractional change in electrical resistivity of this mortar was 82% and this mortar had a compressive strength of 28 MPa.

Is it necessary to calculate Young’s modulus in AFM nanoindentation experiments regarding biological samples?

2020 ◽  
Vol 12 ◽  
Author(s):  
S.V. Kontomaris ◽  
A. Malamou ◽  
A. Stylianou
Keyword(s):  
Young’S Modulus ◽  
Biological Samples ◽  
Young's Modulus ◽  
Reference Sample ◽  
Nonlinear Behavior ◽  
Accurate Method ◽  
Accurate Solution ◽  
Hertz Model ◽  
Work Done

Background: The determination of the mechanical properties of biological samples using Atomic Force Microscopy (AFM) at the nanoscale is usually performed using basic models arising from the contact mechanics theory. In particular, the Hertz model is the most frequently used theoretical tool for data processing. However, the Hertz model requires several assumptions such as homogeneous and isotropic samples and indenters with perfectly spherical or conical shapes. As it is widely known, none of these requirements are 100 % fulfilled for the case of indentation experiments at the nanoscale. As a result, significant errors arise in the Young’s modulus calculation. At the same time, an analytical model that could account complexities of soft biomaterials, such as nonlinear behavior, anisotropy, and heterogeneity, may be far-reaching. In addition, this hypothetical model would be ‘too difficult’ to be applied in real clinical activities since it would require very heavy workload and highly specialized personnel. Objective: In this paper a simple solution is provided to the aforementioned dead-end. A new approach is introduced in order to provide a simple and accurate method for the mechanical characterization at the nanoscale. Method: The ratio of the work done by the indenter on the sample of interest to the work done by the indenter on a reference sample is introduced as a new physical quantity that does not require homogeneous, isotropic samples or perfect indenters. Results: The proposed approach, not only provides an accurate solution from a physical perspective but also a simpler solution which does not require activities such as the determination of the cantilever’s spring constant and the dimensions of the AFM tip. Conclusion: The proposed, by this opinion paper, solution aims to provide a significant opportunity to overcome the existing limitations provided by Hertzian mechanics and apply AFM techniques in real clinical activities.

Microbridge Testing of Thin Films Under Small Deformation

1999 ◽  
Vol 594 ◽  
Author(s):  
T. Y. Zhang ◽  
Y. J. Su ◽  
C. F. Qian ◽  
M. H. Zhao ◽  
L. Q. Chen
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Small Deformation ◽  
Nitride Film ◽  
Silicon Nitride Film ◽  
Pressure Chemical

AbstractThe present work proposes a novel microbridge testing method to simultaneously evaluate the Young's modulus, residual stress of thin films under small deformation. Theoretic analysis and finite element calculation are conducted on microbridge deformation to provide a closed formula of deflection versus load, considering both substrate deformation and residual stress in the film. Silicon nitride films fabricated by low pressure chemical vapor deposition on silicon substrates are tested to demonstrate the proposed method. The results show that the Young's modulus and residual stress for the annealed silicon nitride film are respectively 202 GPa and 334.9 MPa.

Fabrication and Testing of Planar Stent Mesh Designs Using Carbon-Infiltrated Carbon Nanotubes

2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Kristopher Jones ◽  
Brian D. Jensen ◽  
Anton Bowden
Keyword(s):  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Fracture Strain ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Compression Tests ◽  
Element Analysis ◽  
Percent Elongation ◽  
Fea Model

This paper explores and demonstrates the potential of using pyrolytic carbon as a material for coronary stents. Stents are commonly fabricated from metal, which has worse biocompatibilty than many polymers and ceramics. Pyrolytic carbon, a ceramic, is currently used in medical implant devices due to its preferable biocompatibility properties. Micropatterned pyrolytic carbon implants can be created by growing carbon nanotubes (CNTs), and then filling the space between with amorphous carbon via chemical vapor deposition (CVD). We prepared multiple samples of two different stent-like flexible mesh designs and smaller cubic structures out of carbon-infiltrated carbon nanotubes (CI-CNT). Tension loads were applied to expand the mesh samples and we recorded the forces at brittle failure. The cubic structures were used for separate compression tests. These data were then used in conjunction with a nonlinear finite element analysis (FEA) model of the stent geometry to determine Young's modulus and maximum fracture strain in tension and compression for each sample. Additionally, images were recorded of the mesh samples before, during, and at failure. These images were used to measure an overall percent elongation for each sample. The highest fracture strain observed was 1.4% and Young's modulus values confirmed that the material was similar to that used in previous carbon-infiltrated carbon nanotube work. The average percent elongation was 86% with a maximum of 145%. This exceeds a typical target of 66%. The material properties found from compression testing show less stiffness than the mesh samples; however, specimen evaluation reveals poorly infiltrated samples.

scholarly journals Investigation on Nanocomposite Membrane of Multiwalled Carbon Nanotube Reinforced Polycarbonate Blend for Gas Separation

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ayesha Kausar
Keyword(s):  
Carbon Nanotube ◽  
Young’S Modulus ◽  
Gas Separation ◽  
Vinylidene Fluoride ◽  
Young's Modulus ◽  
Multiwalled Carbon Nanotube ◽  
Nanocomposite Membrane ◽  
Polymeric Membrane ◽  
Multiwalled Carbon ◽  
Phase Inversion Technique

Carbon nanotube has been explored as a nanofiller in high performance polymeric membrane for gas separation. In this regard, nanocomposite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multiwalled carbon nanotube (MWCNT) was fabricated via phase inversion technique. Poly(ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nanofiller. Scanning and transmission electron micrographs have shown fine nanotube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young’s modulus of PC/PVFHFP/PEG/MWCNT-A 1–5 were found to be in the range of 63.6–72.5 MPa and 110.6–122.1 MPa, respectively. The nanocomposite revealed 51% increase in Young’s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the permselectivity αCO2/N2 (31.2–39.9) of nanocomposite membrane relative to the blend membrane (21.6). The permeability PCO2 of blend was 125.6 barrer; however, the functional series had enhanced PCO2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1–5; however, filler content did not significantly influence the CO2 and N2 solubility.

Control of stoichiometry, microstructure, and mechanical properties in SiC coatings produced by fluidized bed chemical vapor deposition

2008 ◽  
Vol 23 (6) ◽  
pp. 1785-1796 ◽  
Author(s):  
E. López-Honorato ◽  
P.J. Meadows ◽  
J. Tan ◽  
P. Xiao
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Chemical Vapor Deposition ◽  
Young’S Modulus ◽  
Fluidized Bed ◽  
Vapor Deposition ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Carbide Coatings ◽  
Fuel Particles

Stoichiometric silicon carbide coatings the same as those used in the formation of TRISO (TRistructural ISOtropic) fuel particles were produced by the decomposition of methyltrichlorosilane in hydrogen. Fluidized bed chemical vapor deposition at around 1500 °C, produced SiC with a Young’s modulus of 362 to 399 GPa. In this paper we demonstrate the deposition of stoichiometric silicon carbide coatings with refined microstructure (grain size between 0.4 and 0.8 μm) and enhanced mechanical properties (Young’s modulus of 448 GPa and hardness of 42 GPa) at 1300 °C by the addition of propene. The addition of ethyne, however, had little effect on the deposition of silicon carbide. The effect of deposition temperature and precursor concentration were correlated to changes in the type of molecules participating in the deposition mechanism.

Determination of Young’s modulus of carbon nanofiber probes fabricated by the argon ion bombardment of carbon coated silicon cantilever

Carbon ◽  
2011 ◽  
Vol 49 (13) ◽  
pp. 4191-4196 ◽  
Author(s):  
Kazuhisa Inaba ◽  
Kouji Saida ◽  
Pradip Ghosh ◽  
Ken Matsubara ◽  
Munisamy Subramanian ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Carbon Nanofiber ◽  
Young's Modulus ◽  
Ion Bombardment ◽  
Silicon Cantilever ◽  
Carbon Coated ◽  
Argon Ion Bombardment ◽  
Argon Ion

A Nanoindentation-Based Microbridge Testing Method for Mechanical Characterization of Thin Films for MEMS Applications

2005 ◽  
Author(s):  
Zhiqiang Cao ◽  
Tong-Yi Zhang ◽  
Xin Zhang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Young’S Modulus ◽  
Microelectromechanical Systems ◽  
Mechanical Characterization ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Testing Method ◽  
Chemical Vapor Deposited

Plasma-enhanced chemical vapor deposited (PECVD) silane-based oxides (SiOx) have been widely used in both microelectronics and MEMS (MicroElectroMechanical Systems) to form electrical and/or mechanical components. In this paper, a novel nanoindentation-based microbridge testing method is developed to measure both the residual stresses and Young’s modulus of PECVD SiOx films on silicon wafers. Theoretically, we considered both the substrate deformation and residual stress in the thin film and derived a closed formula of deflection versus load. The formula fitted the experimental curves almost perfectly, from which the residual stresses and Young’s modulus of the film were determined. Experimentally, freestanding microbridges made of PECVD SiOx films were fabricated using the silicon undercut bulk micromachining technique. The results showed that the as-deposited PECVD SiOx films had a residual stress of −155±17 MPa and a Young’s modulus of 74.8±3.3 GPa.

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