Our comprehensive introduction to nanotechnology and nanoscience
with lots of information, examples and images
New Materials: Nanomaterials
Much of nanoscience and many nanotechnologies
are concerned with producing new or enhanced materials.
Nanomaterials can be constructed by 'top down'
techniques, producing very small structures from larger
pieces of material, for example by etching to create circuits
on the surface of a silicon microchip. They may
also be constructed by 'bottom up' techniques, atom
by atom or molecule by molecule. One way of doing
this is self-assembly, in which the atoms or molecules
arrange themselves into a structure due to their natural
properties. Crystals grown for the semiconductor industry
provide an example of self assembly, as does chemical
synthesis of large molecules. A second way is to use
tools to move each atom or molecule individually.
Although this ‘positional assembly’ offers greater control
over construction, it is currently very laborious and
not suitable for industrial applications.
It has been 25 years since the scanning tunneling microscope (STM) was invented, followed four years later by the atomic force microscope, and that's when nanoscience and nanotechnology really started to take off. Various forms of scanning probe microscopes based on these discoveries are essential for many areas of today's research. Scanning probe techniques have become the workhorse of nanoscience and nanotechnology research. Here is a Scanning Electron Microscope (SEM) image of a gold tip for Near-field Scanning Optical Microscopy (SNOM) obtained by Focussed Ion Beam (FIB) milling. The small tip at the center of the structure measures some tens of nanometers.
Current applications of nanoscale materials include
very thin coatings used, for example, in electronics and
active surfaces (for example, self-cleaning windows). In
most applications the nanoscale components will be
fixed or embedded but in some, such as those used in
cosmetics and in some pilot environmental remediation
applications, free nanoparticles are used. The ability to
machine materials to very high precision and accuracy
(better than 100nm) is leading to considerable benefits
in a wide range of industrial sectors, for example in the
production of components for the information and
communication technology, automotive and aerospace