Ab-initio Structural Properties and Stress-Deformation Analysis by Rheological Modeling of Diamonds-containing Nanocarbo
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Ab-initio Structural Properties and Stress-Deformation Analysis by Rheological Modeling of Diamonds-containing Nanocarbon nanotubes Maksim V. Kireitseu1† and Liya Bochkaryova2† 1 Carbon nanotube Nano/Materials Research Center University of New Orleans, New Orleans, LA 70148-2220, USA; E-mail: [email protected] 2 United Institute of Informatics Problems NAS of Belarus ABSTRACT In our laboratory, we developed a simple method for measuring the mechanical properties of single nanotubes and modeling its mechanical properties by rheological analysis. The technique involves depositing nanotubes from a suspension in a suitable liquid onto well- polished alumina ultrafiltration membranes with a pore size of about 200 nm. Rheological models of the composite systems have been proposed and confirmed by in-situ experiments at AFM indentation. INTRODUCTION Critical to the use of nanotubes as a structural material, there is a need for development of nanotube production techniques at the scale needed for producing macroscopic carbon nanotubes that are cost-effective. To unlock the potential of carbon nanotubes for application in polymer/metal/ceramic matrix reinforced nanocarbon nanotubes, one must fully understand the elastic and fracture properties from carbon atom to nanotube, nanofiber etc. as well as the interactions at the nanotube/matrix interface at nanoscale. Challenges in characterization of nanotubes and their carbon nanotubes include (a) Complete lack of micromechanical characterization techniques for direct property measurement, (b) Tremendous limitations on specimen size, (c) Uncertainty in data obtained from indirect measurements, and (d) Inadequacy in test specimen preparation techniques and lack of control in nanotube alignment and distribution. Basic questions are: (a) How do elastic properties of nanotubes depend on the structural details, such as size and chirality? (b) How do elastic properties of nanotubes compare with those of graphite and diamond? Critical mechanical parameters to efficient reinforcement: • Uniform dispersion within the matrix • Improved nanotube/matrix wetting and adhesion • Strong bond at the interface is having a helical conformation of the matrix material around the nanotubes. The binding energies and frictional forces were found to play only a minor role in determining the strength of the interface. DEFINITIONS No agreement in definitions and relations between carbon-based structures were found.
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Graphite or graphene has the form of a 2-D sheet of carbon atoms arranged in a hexagonal array. In this case, each carbon atom has three nearest neighbors. Fullerenes are geometric cage-like structures of carbon atoms that are composed of hexagonal and pentagonal faces (Kroto HW et al. C60: Buckminster fullerene. Nature, 1985). What is the difference between structures? Carbon Nanotubes have several definitions: 1. Carbon nanotubes can be visualized as a sheet of graphite that has been rolled into a tube. Nanotubes exist as either single-walled or multi-walled structures, and m
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