C hapter 1 Nanomaterials and Nanotechnologies: an overview
4
make a green plant green (see Figure 1.2). Inside each chloroplast,
hundreds of thylakoids contain light-sensitive pigments. These
pigments are molecules with nanoscale dimensions that capture
light (photons) and direct them to the photo reaction centers. At
every reaction center, there are light-sensitive pigments that execute
the actual photon absorption. When this happens, electrons become
excited, which triggers a chain reaction in which water and carbon
dioxide are turned into oxygen and sugar.
What is so special about nanotechnology? First, it is an incredibly
broad, interdisciplinary field. It requires expertise in physics, chemistry, materials science, biology, mechanical and electrical engineering,
medicine, and their collective knowledge. Second, it is the boundary between atoms and molecules and the macro world, where
ultimately the properties are dictated by the fundamental behavior
of atoms. Third, it is one of the final great challenges for humans, in
which the control of materials at the atomic level is possible. So, are
nanoscience and nanotechnology real, are they still fiction? During
the 1990s Drexler’s book Engines of Creation inspired many science
fiction writers to think about the prospects of nanotechnology. For
example, in the episode “Evolution” of Star Trek, a boy releases
“nanites,” which are robots at the nanoscale fabricated to work in
living cells. These machines end up evolving into intelligent beings
that gain control the starship Enterprise. In the book Queen of Angels,
humans with psychological problems can be treated by an injection
of nanodevices. These fictional ideas could become reality if in the
future we become able to control matter at the atomic or molecular
level. Yet, some skeptical questions may arise, such as:
■ Are molecular entities stable?
■ Are quantum effects an obstacle to atomic manipulation?
■ Is Brownian motion a significant effect in nanocomponents?
■ Are friction and wear relevant for nanocomponents?
The answer to the first question is yes. The human population is
the best living example. Each human being contains approximately
10
27 atoms that are reasonably stable, and due to cellular multiplication, the human body is able to build itself using molecular mechanisms. With respect to the quantum effects, the uncertain atomic
position (Δx) can be estimated from classical vibrational frequency
calculations. As discussed by R. Freitas in his book Nanomedicine,
for a carbon atom in a single C-C bond, Δx is approximately 5%
of the electron cloud diameter. Hence, the manipulation of nanoFigure 1.2
A green leaf is composed of chloroplasts inside
which photosynthesis occurs.
4
make a green plant green (see Figure 1.2). Inside each chloroplast,
hundreds of thylakoids contain light-sensitive pigments. These
pigments are molecules with nanoscale dimensions that capture
light (photons) and direct them to the photo reaction centers. At
every reaction center, there are light-sensitive pigments that execute
the actual photon absorption. When this happens, electrons become
excited, which triggers a chain reaction in which water and carbon
dioxide are turned into oxygen and sugar.
What is so special about nanotechnology? First, it is an incredibly
broad, interdisciplinary field. It requires expertise in physics, chemistry, materials science, biology, mechanical and electrical engineering,
medicine, and their collective knowledge. Second, it is the boundary between atoms and molecules and the macro world, where
ultimately the properties are dictated by the fundamental behavior
of atoms. Third, it is one of the final great challenges for humans, in
which the control of materials at the atomic level is possible. So, are
nanoscience and nanotechnology real, are they still fiction? During
the 1990s Drexler’s book Engines of Creation inspired many science
fiction writers to think about the prospects of nanotechnology. For
example, in the episode “Evolution” of Star Trek, a boy releases
“nanites,” which are robots at the nanoscale fabricated to work in
living cells. These machines end up evolving into intelligent beings
that gain control the starship Enterprise. In the book Queen of Angels,
humans with psychological problems can be treated by an injection
of nanodevices. These fictional ideas could become reality if in the
future we become able to control matter at the atomic or molecular
level. Yet, some skeptical questions may arise, such as:
■ Are molecular entities stable?
■ Are quantum effects an obstacle to atomic manipulation?
■ Is Brownian motion a significant effect in nanocomponents?
■ Are friction and wear relevant for nanocomponents?
The answer to the first question is yes. The human population is
the best living example. Each human being contains approximately
10
27 atoms that are reasonably stable, and due to cellular multiplication, the human body is able to build itself using molecular mechanisms. With respect to the quantum effects, the uncertain atomic
position (Δx) can be estimated from classical vibrational frequency
calculations. As discussed by R. Freitas in his book Nanomedicine,
for a carbon atom in a single C-C bond, Δx is approximately 5%
of the electron cloud diameter. Hence, the manipulation of nanoFigure 1.2
A green leaf is composed of chloroplasts inside
which photosynthesis occurs.