Information Technology Reference
In-Depth Information
laser beam
cantilever
cantilever
substrate
substrate positioning
Fig. 1.15 Scheme of the atomic force microscope
Fig. 1.16 Images obtained on an atomic force microscope (see text for explanations)
beginning of the 1930s by the English physicist London and was dubbed dispersion
interaction. It is also known as van der Waals interaction.
Atomic force microscope uses dispersion interaction between the atoms of the
needle tip and the surface of the investigated sample (Fig.
1.15
). The needle is fixed
to an elastic support—cantilever. The displacement of the tip due to dispersion
interaction is described by Hooke's law, i.e., it is determined by the strength of the
dispersion force and the elasticity of the cantilever. It is usually measured by
registering the laser beam reflected by the cantilever with a photodiode matrix.
Today atomic force microscopy is a powerful method for studying the structure
of diverse objects, including also the biological ones, and is widely used in research
practice. Some of the typical examples are shown in Fig.
1.16
: (a) carbon nanotubes
(2
2
μ
m), (b) natural rubber (20
20
μ
m), (c) MoO
3
crystallites on a MoS
2
substrate (8
m), and (d) chromatin, a complex consisting of proteins and
DNA which is part of the chromosomes (400
8
μ
400 nm).
1.3 Nanotechnology at the State Level
A turning point in the advent of nanotechnology as a distinct area of engineering
and technology was the development in the United States of a document called
“National Nanotechnology Initiative. Leading to the next industrial revolution.”
Formally this document was a report of the Interagency Working Group on
