Atomic force microscopy Young moduli

Davies, M., Brindley, A., Chen, X., et al. (2005), Characterization of drug particle surface energetics and Young s modulus by atomic force microscopy and inverse gas chromatography, Pharm. Res., 22,1158-1166. 

Atomic force microscopy (AFM) has been used to determine the bending force of suspended MWNTs pinned at one-end to a molybdenum disulfide surface. The MWNTs with diameters from 26 to 76 nm show an average Young s modulus of 1.28 0.59 TPa. The determined Young s modulus has no dependence on the diameter of MWNTs. The bending strength calculated for the MWNTs is around... 

Different modes of operation of AFM may be applied to the characterisation of biopolymers. As biopolymers differ in their rigidity (Young s modulus), their responses to the normal and sheer forces apphed by the AFM tip will also differ. As different modes of AFM are available, the user can forego resolution in order to minimise sample distortion (as in the case of tapping mode atomic force microscopy), or improve the resolution using noncontact or cryogenic AFM. 

Keywords a-Helical coil spring Atomic force microscopy Force spectroscopy Mechanical unfolding of a-helix Peptide hydrogen bond Tensile mechanics of a-helix Young s modulus... 

Chrysotile NTs were synthesized and characterized by Piperno and co-workers (2007) using atomic force microscopy and transmission electron Microscopy (TEM). The results have shown that chrysotile NTs exhibit elastic behavior at small deformation. The chrysotile Young s modulus evaluated by (Piperno et al, 2007) are 159 + 125 GPa. The stoichiometric chrysotile fibers demonstrate a hollow structure with quite uniform outer diameter around 35 nm and inner diameter about 7-8 nm. The NTs are open ended with several hundred nanometers in length. 

Kitano H, Yamamoto A, Niwa M, Fujinami S, Nakajima K, Nishi T. Young s modulus mapping on hair cross-section by atomic force microscopy. Compos Interfaces 2009 16 1-12. 

H. Ni, X.D. li. Young s modulus of ZnO nanobelts measured using atomic force microscopy and nanoindentation techniques. Nanotechnology 17(14), 3591-3597 (2006)... 

W.J. Price, S.A. Leigh, S.M. Hsu, T.E. Patten, G.Y. Liu, Measuring the size dependence of Young s modulus using force modulation atomic force microscopy. J. Phys. Chem. A 110(4), 1382-1388 (2006)... 

With atomic force microscopy it is possible to realize a 3D nanoscale topography of nanostructures, and define nanowrinkledness profiles. The principal parameters (e.g. Young s modulus) and properties (e.g. V-/ characteristic) of carbon nanotubes have been determined by the tip of the AFM cantilever. Figure 6.28 illustrates an example of carbon nanotubes deposited on a Si substrate and analysed by AFM. The lines marked as red and green show nanometric sample profiles. The relative statistical characterization is reported in the table. 

The deformation behavior of bulk ZnO single crystals was studied by a combination of spherical nanoindentation and atomic force microscopy [101]. ZnO exhibited plastic deformation for relatively low loads (>4—13mN with a 4.2 mm radius spherical indenter). The average contact pressure hardness H and Young s modulus as a function of indenter penetration were determined by analyzing partial load-unload data. The hardness value of ZnO is measured to be 5.0 0.1 GPa at a plastic penetration depth of 300 nm. The Young s modulus remained essentially constant over the indenter penetration depth, with =111.2 4.7 GPa. Previous indentation studies performed mostly on polycrystalline ZnO have reported a wide range of H ( 1.5-12 GPa) and ( 40-120 GPa) values. However, it should be noted... 

E. Kester, U. Rabe, L. Presmanes, Ph. Tailhades, and W. Arnold, Measurement of Young s Modulus of Nanocrystalline Ferrites with Spinel Structures by Atomic Force Acoustic Microscopy J. Phys. Chem. Solids 61, 1275 1284 (2000). 

This paper discusses the type of fracture events which occur for hard coatings on soft and hard substrates and outlines the effect that fracture events have on other mechanical properties measured by indentation (such as hardness and Young s Modulus). It also introduces the use of acoustic emission generation to monitor fracture events in very thin coatings where it is difficult to identify them by conventional microscopy (both scanning electron and atomic force). 

Many techniques have been developed to measure the Young s modulus and the stress of the mesoscopic systems [12, 13]. Besides the traditional Vickers microhardness test, techniques mostly used for nanostructures are tensile test using an atomic force microscope (AFM) cantilever, a nanotensile tester, a transmission electron microscopy (TEM)-based tensile tester, an AFM nanoindenter, an AFM three-point bending tester, an AFM wire free-end displacement tester, an AFM elastic-plastic indentation tester, and a nanoindentation tester. Surface acoustic waves (SAWs), ultrasonic waves, atomic force acoustic microscopy (AFAM), and electric field-induced oscillations in AFM and in TEM are also used. Comparatively, the methods of SAWs, ultrasonic waves, field-induced oscillations, and an AFAM could minimize the artifacts because of their nondestructive nature though these techniques collect statistic information from responses of all the chemical bonds involved [14]. 

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