Geoscience Reference
In-Depth Information
opened up a new chapter in materials processing. It is being popularly referred to as
multienergy processing of materials. Hitherto, in the hydrothermal technique, the
researchers were dealing only with the temperature, pressure, and chemical potential
as the three main variables in materials processing, and much of the thermodynamic
issues have been understood more or less precisely. But with the additional energy
variables in the system, the thermodynamic relationship reads completely differently
and becomes more complicated. This forms the future of materials processing,
which can be termed as novel methods of advanced materials processing
[6,7]
. From
2010, researchers are using the concept of instant hydrothermal reactions to obtain
the desired nanoparticles in a shortest possible time and some even imagine a system
like a vending machine to produce the desired nanoparticles with definite physical
properties
[8]
. This leads us to the concept visualized by an eminent American
Energy Department consultant as chemistry at the speed of light
[9]
. There are so
many advantages in such a multienergy concept of advanced materials processing.
The credit for this multienergy processing goes to the researchers at the Tokyo
Institute of Technology, who first attempted hydrothermal reactions with electro-
chemical and mechanical energies, which firmly established a new trend in materials
processing in 1970s and 1980s
[10]
. Followed by this, the Materials Research
Laboratory at the Penn State well explored the possibilities of microwave and sonar
in the hydrothermal reactions in 1990s and went on to become the world leaders in
this fascinating area of science
[11,12]
.
The discovery of hydrothermal activity in the deep sea during 1970s
[13]
has led
to a new thinking in marine biology and geochemistry, which set a new trend in
advanced materials processing. Now it is strongly believed that the roots of life on
earth can be found in hydrothermal ecosystems. Thus, the organic synthesis under
hydrothermal conditions was established, which has now become an important area
of research. The organic
inorganic hybrid materials are forming the core of the
nanotechnology, which insist on the precise control over the size and morphology of
the nanoparticles that influence directly the physical properties because of size quan-
tization
[14]
. As we know, earth is a blue planet of the universe where water is an
essential component. Circulation of water and other components such as entropy
(energy) are driven by water vapor and heat (either external or internal). Water has a
very important role in the formation of material or transformation of materials in
nature, and hydrothermal circulation has always been assisted by bacteria, photo-
chemical, and other related activities.
Table 10.2
gives some representative bioas-
sisted materials
[15]
. Such an understanding helps in the processing of advanced
inorganic materials with the assistance of biomolecules, e.g., proteins, organic
ligands, DNA, and amino acids. A great variety of biomaterials can be fabricated
under ambient conditions by employing the nature-inspired conditions. Yoshimura
[16
18]
is popularizing a new concept called Soft Solution Processing, from 2000
one decade, as the process which is inspired basically by the natural processes. It
covers all set of materials processes, which can be operated under ambient or near
ambient conditions or just above the ambient conditions to prepare a wide range of
materials including even complex and high melting materials. The basis of the soft
solution processing concept of Yoshimura is based on the nature-inspired processes
