Ultrasonic force microscopy stiffness

Ultrasonic force microscopy is able to give contrast from samples over a wide range of elastic properties, from stiff crystalline materials like semiconductors... 

Dinelli, F., Biswas, S. K., Briggs, G. A. D., and Kolosov, O. V. (2000a). Measurements of stiff-material compliance on the nanoscale using ultrasonic force microscopy. Phys. Rev. 5 61(20), 13995-14006. [300]... 

In an Atomic Force Acoustic Microscopy set-up [3-5] either the sample is insonified or the cantilever suspension is excited at ultrasonic frequencies. The vibration spectra of the cantilever depend on the local sample stiffness and hence... 

Yuya et al. [243] extracted the elastic modulus of single electrospun PAN nanofibre dynamically through the natural frequencies of a pair of AFM microcantilevers linked by a nanofibre segment (Fig. 4.24b). The theory of this technique is based on the dynamic relationship between the fibre stiffness (i.e. spring constant) and the resonance frequencies of cantilever vibration mode. On the other hand, Liu et al. [244] used atomic force acoustic microscopy (AFAM) based on ultrasonic frequency oscillations to excite an AFM cantilever when the tip was in contact with a sample. A different approach based on a model of the resonant frequency that is dependent on the bob s free flight was employed to measure the elastic modulus of as-spun nylon 6, 6. A ball was glued to a nanofibre and suspended from a cantilever beam that was attached to a piezoelectric-actuated base [245]. 

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