Chemistry Reference
In-Depth Information
scanning tunnelling microscope (STM) by Binning and Rohrer [
1
-
4
] (Nobel Prize
in 1986). This new imaging technique led then to the discovery of fullerenes [
5
,
6
]
by R. Smalley, R. Curl, J. Heath, S. O'Brien, and H. Kroto in 1985 (Nobel Prize in
1996). In addition the giant magnetoresistance was co-observed on Fe/Cr/Fe tri-
layers by P. Grünberg and his group [
7
] and independently on Fe/Cr multilayers by
A. Fert and his group [
8
] in 1986 (Nobel Prize in 2007), originating the so-called
spintronics. Thus, large efforts were essentially devoted in 1990s to the elaboration
of well controlled, tunable and reproducible nanostructures including multilayers,
and nanostructured powders and the synthesis of nanoparticles by means of dif-
ferent routes with well controlled chemical conditions. Such an approach makes
easier the characterization of the nanomaterials and the understanding of their
physical properties, increasing their role and the emergence of nanosciences and
nanotechnologies. On the contrary, it is obvious but important to emphasize that
the non homogeneous structural and morphological properties combined to a lack
of reproducibility and time stability prevent definitively from a clear understanding
and realistic modelling of the physical properties of these nanomaterials.
During the last decade, the developments in nanotechnology which consists in
the studies and processes to manipulate solid matter at the nano and/or molecular
scale received a large and explosive debate with social and ethical issues: new
policies and regulations on the use of nanotechnologies have to be established.
Indeed, nanotechnology aims to design new functional smart materials and devices
with a wide range of applications: it is important to emphasize the emergence of
new topics such as nanomedicine, nanoelectronics, nanobioengineering, nanofo-
ods, nanoweapons, … . The developments associated to these areas do substan-
tially contribute significant benefits in improving drug delivery, diagnostics and
tissue engineering, water and waste treatment, stain-resistant clothes, protective
nanopaint, reducing energy consumption, using more environmentally friendly
energy systems, increasing information and communication storage, making
construction and heavy industry cheaper (weight reduction), faster and safer with
nanocomposites, in introducing nanosensors in foods packaging and security
devices. However, some aspects concerned by the risks, toxicity and environ-
mental impact of nanomaterials have to be considered. Consequently, both the
batch-to-batch reproducibility and the high control of the morphology of
nanomaterials have to be systematically checked at the atomic scale, together with
their performances, stability and (bio)compatibility, in view of their potential
applications, requiring thus the use of a wide set of complementary and specific
techniques.
It is first important to classify the different types of nanostructures and their
relevant characteristics and morphological features at the nanoscale, according to
their dimensionality, as illustrated in Fig.
4.1
. One can clearly distinguish 0D
nanostructures with nanoparticles, clusters and mesoporous systems as MOFs
(Metal Oxide Frameworks), 1D nanostructures with nanotubes and nanowires, 2D
nanostructures with multilayers and 3D nanostructures with nanostructured and
nanocrystalline materials. In this context, nanocrystalline materials are defined as
single- or multi-phase polycrystalline solids with a grain size of a few nanometres
