Atomic force microscopy surface defects

Nanostructured materials have also been formed by scanning tunneling microscopy (STM) [24], scanning electrochemical microscopy (SECM) [25], and atomic force microscopy (AFM) [26], Recent reports on the modification of atomic sites at bare surfaces by STM [27] and the formation of nanometer-scale defects by STM [28] and AFM [29] illustrate the power of these techniques. 

Fig. 7 Atomic force microscopy image illustrating defect structures in wrinkled surfaces prepared by plasma treatment of stretched PDMS and subsequent relaxation...

Photoreceptors may be characterized by optical microscopy for layer structure and architecture. Surface defects may be characterized by atomic force microscopy. Scratch resistance can be characterized by scratching the photoreceptor surface with a stylus of known dimensions under specified loads. Brittleness measurements are... 

Characterization tools must also be developed if a fundamental understanding of corrosion is to be achieved. For example, observation of a titanium surface with an oxide film at the nanometer scale shows oxide grains on the surface. Conductivity atomic force microscopy measurements can be used to indicate defect-free Ti02 by showing no current flow. This is visually indicated by a dark image. 

T.G. Strange, R. Mathews, D.F. Evans, and W.A. Hendrickson, Scanning tunneling microscopy and atomic force microscopy characterization of polystyrene spin coated onto silicon surfaces, Langmuir 8, 920 (1992) U. Okoroanyanwu, J. Cobb, P. Dentinger, P, C. Henderson, V. Rao, and C. Pike, Defects and metrology of ultrathin resist films, Proc. SPIE 3998, 515 (2000). 

External surface features of fibers such as contours, defects and damagp, chemical treatments, and polymer coatings are normally observed in the SEM (Figure 5.4). Recent developments in atomic force microscopy (AFM) should expand the potential to provide ultrahigh-resolution data about surface features at the atomic and the molecular levels. Thus, a complementary array of techniques is now available for detailed surface studies. 

Finally, we note that the predictions from these simulations could be directly probed with surface spectroscopies such as sum frequency generation (SFG) spectroscopy [16]. Provided self-assembly of SAMs of different chain lengths was possible, adsorption of LKo(14, we predict, would reveal no appreciable SFG signal compared to neat SAMs, which reveal the expected helical structures. Likewise, using a combination of techniques such as surface plasmon resonance (SPR) and atomic force microscopy (AFM) [41], we propose it would be possible to study the expected increases in binding energy due to the film formation defects. Of course, this would depend on being able to synthesize in a controlled way the film-type defects. 

Asif, S.A.S., Wahl, K.J. and Colton, R.J., The influence of oxide and adsorbates on the nanomechanical response of silicon surfaces. J. Mater. Res., 15,546-553 (2000). Bhushan, B., Kulkami, A.V., Bonin, W. and Wyrobek, J.T., Nanoindentation and picoin-dentation measurements using a capacitive transducer system in atomic force microscopy. Philos. Mag. A Phys. Condens. Matter Struct. Defects Mech. Prop., 74(5), 1117-1128 (1996). 

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