2. What Do You Know About It?
Why do you think these materials are
piece of news? Which features do they
have to be considered as new materials?
Which is your opinion and your personal
interest about these new materials?
Carbon fiber, optical fiber and carbon
nanotubes are usually in nature or they
have been synthesized artificially? How do
you know it? Read your textbook
3. Which other natural or synthetic materials
do they replace? Which improvements do
they show regarding the older ones?
Considering the definition of carbon
nanotubes and the explanation about what
scientists do with them, how would you
define nanotechnology? Which impact may
it have in other fields, besides biomedicine?
According to you, which problems could be
originated by these and other new
materials?
4. Materials Science
Materials
science is the name we give to
the field of science and engineering that
studies the relations between materials
structure and its properties and also its
processing techniques and its behavior
Materials have been historically related with
economic and social development
5. We may divide Prehistory in
Copper Age,
Bronze Age or Iron Age, according to the
metal or alloy they used then
Present-day society lives in Silicon Age,
because of the significance of Electronics
The 20th century is considered Plastic Age
Materials that a society owns are a mirror
of its lifestyle, its knowledge and scientific
and technological abilities
6.
7. Materials Science is an interdisciplinary
science: one material is featured by its
physical and chemical properties but also by
its biological compatibility
It is an applied science, because its aim is
not only knowing materials, but also
processing them and designing objects that
be useful at an economic and environmental
sustainable cost
Physical properties : density, thermal
conductivity, electric resistivity, magnetic
permeability, elasticity, hardness, fragility...
8. Chemical properties: reactions that
transform material’s nature, oxidation,
acidity or alkalinity (reaction against pH),
chemical stability in general
Biological compatibility
is regarded
whether material can be used in
organisms or living tissues without
provoking immunologic rejection or non
desired toxic effects
9. Structure:
Atomic, Micro and Macro Levels
At an atomic scale we are interested in
which atoms or molecules constitute them
Which type of interactions do exist between
them: metallic, ionic or covalent bonds, Van
der Waals forces, hydrogen bonds
Which type of organization do they contain:
crystalline (ordered) or amorphous
(disordered)
10.
Microstructure refers to whether it is formed by
fibers, tubes, sheets or microscopic pores
Macrostructure refers to the aspect at our scale:
visible parts of a material composed of many
others
We must know that one material’s behavior
(“all”) does not equal the addition of its
components (“parts”)
Defects play an important role. Perfect crystals
are impossible to obtain, but interesting
properties stem from their defects: interstitial
elements, empty positions and substitutions.
Many materials are amorphous
11. Metals and New Metallic Materials
According to their origin, materials can be
natural or artificial. According to their structure
and properties there are three main groups:
metals, ceramics and polymers. There are also
composed materials from those groups
Metals are electropositive, easily give or share
electrons. They have a structure made up of
crystal lattices formed by positive ions
surrounded by free electrons that can be given
to more electronegative elements and form ionic
bonds or share between metals (metallic bonds)
12.
Properties: good heat and electricity conductors,
high density, solid at ordinary temperature (high
melting points), light reflecting (metallic
brightness), they are hard, ductile and
malleable. Some have magnetic properties (Fe,
Co, Ni), others (Au, Pt, Ag, Cu, Al) have a very
weak magnetism
They form alloys with each other. An alloy is a
solid mixture of different metals. Their original
properties are modified: color, mechanical
resistance, resistance to corrosion. The first one
to be found in history was bronze: copper and
tin, it improved hardness and resistance of
copper and started the age of metallurgy
13. NEW METALLIC MATERIALS: the most
interesting innovation in the world of metals
is the production of shape-memory alloys.
After being deformed they have the capacity
of remembering their earliest shape,
because deformations are displacements of
the original crystal lattice. The new lattice is
not much symmetrical and becomes
unstable. When you heat it up or set it free,
the structure goes back to the earlier
situation and metal recovers its original
shape (Nitinol: nickel and titanium)
17. Ceramics and New Ceramic Materials
Traditional ceramics
are made up of
silicates and have been used in
craftsmanship (clay, porcelain) and
structural materials (bricks, glass, concrete)
Technical or advanced ceramics contain
metallic and non-metallic elements making
up oxides (Al, Zr), carbides, nitrates and
borates
18. Applications: space shuttle covering, engine
components, artificial bones and teeth,
electronics, powerful magnets, optic fibers,
cutting tools, ovens and sensors
All ceramics have in common that they are
refractory, inorganic and non-metallic
materials
They are usually crystalline, excepting
glasses that are amorphous, and have very
strong ionic or covalent bonds
19. Ceramics are prepared from powder,
natural or chemically synthesized, in
ovens at very high temperatures (15002400 °C)
They have a low thermal and electrical
conductivity (some are semiconductors
and other even superconductors at very
low temperatures), they have a high
hardness (like diamonds) but are also
fragile (breakable) and not much plastic.
They are resistant to corrosion
20. New ceramic materials
have very different
uses
Smart ceramics are used in sensors and
actuators, like electrochromic glasses, that
change their color with heat, or piezoelectric
or pyroelectric sensors, that detect changes
in mechanical tension or temperature and
convert them into electrical voltage
As a future challenge there are
hyperfiltration ceramic membranes at a
molecular scale and superhard ceramics to
make coverings and improving their ductility
21.
22. Polymers
Formed by very large molecules, of an
organic origin usually
Some structural units, called monomers,
are repeated. They are united by means
of covalent bonds
Frequently polymers are related with
plastics, but cellulose, DNA and proteins
are also polymers
23. Some polymers with a
natural origin are
well known from ancient times: silk, rubber,
shellac
The ones we usually use today are mainly
synthetic: tissues, packing, frames for toys
and electric devices, cable and electric
components insulation
Properties: mechanical resistance (capacity
to bear tensions without breaking) and
elasticity (capacity to deform without
breaking)
24. Specific properties
of a polymer depend
on the monomer and type of bond formed:
Van der Waals forces, hydrogen bonds
By combining resistance and elasticity
different kinds of polymers are obtained:
rigid fibers, flexible plastics, elastomers
They have a low electric and thermal
conductivity, because of containing
covalent bonds where electrons are
immobilized and due to the long size of
monomers that makes vibration difficult
26. PLASTICS FLOATING AT “THE GREAT PACIFIC GARBAGE PATCH”
http://www.youtube.com/watch?v=uLrVCI4N67M
http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patch
27.
28. Biomaterials
These materials are
compatible with living
tissues and organisms with which they
interact
Many of them are used in medical
applications: metals like titanium or
biocompatible ceramics for practicing
bone implants with the minimum patient’s
rejection and systems to supply medicines
with a time regulation
29.
30. Materials for a More Efficient
World: Carbon Fiber
Very well known material because of its
extraordinary resistance and lightness,
what allows to reduce fuel use in transport
The high manufacturing costs have made
it to have an elitist use until now
It is about a composed material,
manufactured from a polymer matrix
(epoxy resin) reinforced with carbon fibers
31.
Each fiber is made up of thousands of carbon
filaments between 5 and 8 μm diameter
As it is a composed material it combines
features from the matrix (sticky, hard and elastic
resin) with those of fibers (very resistant) to form
a “tissue” with a high resistance, lightness and
elasticity
It’s the very best material for frames that can be
designed to measure
It is good for thermal insulation and has fireretardant properties
The only inconvenient is a high manufacture
cost
38. Materials for a More Global World:
Optic Fiber and LED
Without optic fiber nor light emitting
semiconductor diodes (LED), the Internet
would not have been possible
Long distances, where information has a
long way to run, demand materials where
signals do not fade too much
Optic fiber is needed to transmit great
volumes of information (broadband)
39.
40. Optic Fibers
They are made up of glass (ceramic material) or
plastic (polymer)
They are obtained making melt glass flow at a
very high temperature through a mesh with very
thin holes and form filaments that, once they are
solidified, they keep enough elasticity to be used
as fibers
They have the same properties we know from
glass: good electric and thermal insulation, high
temperatures support and transparency
They have both a low cost and row material
abundance
41. Optic fibers conduct light
without almost
any fading and in curve trajectories
The phenomenon of total reflection inside
the fiber is applied
42. As fibers can be made very thin, cables
with optic fiber transmit much more
information than traditional copper cables
They are, besides, light, flexible, cheap
and do not go rusty
Optic fiber is not only used to transmit
digital information, its simplest application
is transmitting light into places difficult to
accede, say, inside the human body:
endoscopies, laser surgery…
They are also used as sensors of all kinds
44. Laser Diodes and LED
The use of optic fibers has been parallel to
the development of new less expensive
means to produce light, say, laser diodes
(on pointers) and LED (light-emitting diode)
It is about semiconductor ceramic devices
(with insulating and conducting properties)
that emit light when they are connected to
an electric current in one specific direction
but they do not let the current pass if they
are connected in the contrary direction
45. They have the advantage of being
little,
energy-saving (use of 50 % less than
traditional sources), easy to replace,
cheap and lasting
We are now having LED of different colors
and also of white light that will help to save
energy when they replace present-day
devices
47. Nanotechnology
The new materials we have seen until now
are obtained by modifying internal
composition, microstructure or
macrostructure, but always to a
macroscopic scale
A great revolution has begun with the
possibility of making a scale change
It consists in treating materials to a scale
between atomic and molecular
Nanotechnology is part of materials
science at this new scale
48. It is foreseen that nanotechnology will
have an impact in our lives similar to that
of electricity in its time or modern transport
systems
We should think what could mean to
medicine news like the ones we read at
the beginning of this unit regarding the
technique to attack malignant tumors or to
cure diabetes 1, now in a phase of testing
There is a long way to run full of
advantages, but there could also be some
risks
49. The Nano Scale
The name comes from the fact that the atomic
and molecular scale is about nanometers (1 nm
= 10-9 m)
It is very difficult to manage objects there,
because physical and chemical laws change:
gravity is too weak and other interactions, like
the Van der Waals forces, become essential
Besides, the quantum effects cannot be
despised: matter behaves in a dual way, both as
a wave and as a particle, there is quantization of
energy and uncertainty: we are not able to
calculate once at a time one particle’s
momentum and its position
50.
51. New Instruments
Nanotechnology is possible thanks to the
development of new instruments to explore
nature at the new scale
The first one was the STM, scanning
tunneling microscope, in which a tungsten
point containing ONLY ONE ATOM in its
head makes a scan and measures the
electric nanocurrents generated between
the point and the sample. Atoms cannot be
“seen”, instead we can infer their position
while scanning the sample (photo page 174
on your textbook)
54. New Instruments
At present we also use the
AFM, atomic
force microscopes, that measure the force
between a scan flexible microlever and the
sample and can be used with nonconductor samples
56. Biomimetic Nanotechnology
Nanotechnology intends to imitate life
and
is inspired in living structures, like DNA,
that are actually nanomolecules and so
does all the intracellular working structure ,
containing many other “nanomachines”,
sets of molecules that do a lot of functions
57. Nanofuzziness of lotus leaves , when they
are wet, they form water drops that carry
dirtiness away from leaves. This can be
applied to out-door paintings and sanitary
ceramic, where water slips and keeps
them clean
Salamanders have very slender hairs
that
are placed at nanometric distances from
the surfaces and pull through Van der
Waals forces. Synthetic hairs can interest
the world of adhesives
58. Sponge called “Venus’s basket” forms an
inner skeleton with silica needles and a
weft similar to a wicker basket. Sponge
cells join together in extra-thin layers with
nanometric silicon oxide blocks and then
they wind up and form the needles . The
result is a material with a big resistance
and high packaging which is considered
as a biological model for a future optic
fiber design
http://mentescuriosas.es/8-ejemplos-de-inventos-inspirados-en-la-naturaleza/
60. Carbon Nanotubes
Carbon nanotubes are a type of
fullerenes,
tridimensional carbon molecules with
different shapes and properties. The ones
with a cylinder shape are called nanotubes
Nanotubes have an extraordinary
mechanical resistance, although they are
very light, and electrically they are from
semiconductors to superconductors and
they have a high heat conductivity
61. ALLOTROPES
OF CARBON
a) diamond; b) graphite; c) hexagonal diamond; d) fullerene C60; e) fullerene C540
f) fullerene C70; g) amorphous carbon; h) carbon nanotube
62.
63.
64.
65. WOULD THE NEW MATERIALS BE ABLE
TO COME THESE DREAMS TRUE?
66. To Learn More
MIJANGOS, Carmen; MOYA, José
Serafín (coord.) Nuevos materiales en la
sociedad del siglo XXI. Madrid: CSIC,
2077
Disponible en línia a:
www.csic.es/documentos/colecciones/divulg
acion/materiales.pdf
SCHULENGURG, Mathias. La
nanotecnología. Innovaciones para el
mundo del mañana. Luxemburg: Comissió
Europea, 2004
67. Està disponible en línia a:
ftp://ftp.cordis.europa.eu/pub/nanotechnolog
y/docs/nano_brochure_es.pdf
The Nanotube Site:
http://nanotube.msu.edu/
CRICHTON, Michael. Presa. Barcelona:
Círculo de Lectores, 2004 (Ciència ficció)
Crítica a:http://www.nanotechnow.com/Chris-Phoenix/prey-critique.htm
STEPHENSON, Neal. La era del
diamante. Barcelona: Ediciones B, 2004
