This document discusses nanotechnology, highlighting its significance in various fields such as energy, medicine, and materials science, where nanoscale manipulation of materials leads to enhanced properties and new applications. It explains the classification of nanomaterials, the unique characteristics arising from their small size, and potential uses in everyday products like clothing and sunscreens. Additionally, it addresses the risks and health concerns associated with nanotechnology, including potential adverse effects on humans and the environment due to the unique properties of nanoparticles.

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MM 101
Materials and Nanotechnology
Spring 2024

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https://www.youtube.com/watch?v=OLa8DQkKlyU

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Technology:
 Technology is the application of knowledge for practical
purposes. Products are tangible (e.g., machines), and intangible
(e.g., software).
 It involves the application of scientific knowledge, engineering
skills, and practical experience to design, build, and operate
various devices, machines, software, and systems that make our
lives easier, more efficient, and more productive.
 technology is the key driver of economic growth of countries,
regions and cities.
Nanotechnology
Nanotechnology is the branch of technology that deals with
dimensions less than 100 nanometers, especially the manipulation of
individual atoms and molecules.
It’s the designing, characterization, production and application of
structures, devices and systems by controlling shape and size at
nanometer scale.
Applications are wide and varied, including energy production and
storage, drug delivery, materials science, and many others.

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HOW SMALL IS
NANO ?

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Nanomaterials
Nanomaterials may be classified as those materials which have at least
one of their dimensions in the nanometric range.
 Below which there is significant variation in the property of interest
compared to microcrystalline materials.
 Nanocrystalline materials have a grain size of the order of 1−100 nm.

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CLASSIFICATION OF
NANOSTRUCTURED MATERIALS

7. Quantum dots (0D)
Quantum dots (QDs) are man-made nanoscale
crystals that exhibit unique optical and
electronic properties, including the ability to
transport electrons and emit light of various
colors when exposed to UV light
Quantum dots are tiny particles or nanocrystals
with diameters in the range of 2-10 nanometers
(10-50 atoms).

8. Carbon nanotubes (1D)

9. Nanotechnology
What make technology at the nanoscale
different from technology at the macroscale?

10. Volume to surface area ratio
• As objects get smaller
they have a much
greater surface area to
volume ratio
2 cm cube has
a surface area
of 24 cm2 and a
volume of 8 cm3
(ratio = 3:1)
10 cm cube has a
surface area of 600
cm2 and a volume of
1000 cm3 (ratio =
0.6:1)
 Materials at the nanoscale have
a greater surface area to
volume ratio than their bulk
counterparts.
 The relative concentration of
under-coordinated surface
atoms is thus greater for
nanomaterials compared to their
bulk form

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From macro- to nanomaterials: the effect on the surface area

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13. Size
Nanoparticle Nanoparticle Volume Surface Area SA:Vol Ratio
Diameter (nm) Diameter (um) (nm3) (nm2) (nm2/nm3)
1 0.001 0.524 3.14 6
10 0.01 524 314 0.6
100 0.1 523598 31416 0.06
1000 1 5.24E+08 3.14E+06 0.006
10000 10 5.24E+11 3.14E+08 0.0006
100000 100 5.24E+14 3.14E+10 0.00006
1000000 1000 5.24E+17 3.14E+12 0.000006
Some example calculations for volume and surface area of nanoparticles. These calculations use nm as
unit of length.

14. Physical properties
• At very small sizes physical properties (magnetic, electric and optical)
of materials can change dramatically.
 As quantum confinement effects change the
electronic structure of the nanomaterial
(nanomaterials start to have discrete electronic states,
while the bulk material has essentially continuous
electronic states).
 band structure of the nanomaterial changed and
consequently modulate its optical and transport
properties (i.e., electrical and thermal transport).
 quantum confinement: small and finite separation between energy levels based on
Materials with structure at the nanoscale often
have unique optical, electronic, thermal (heat),
or mechanical properties.

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3. Nanoparticles: Coating

16. • Coatings - self-cleaning windows and stainproof clothing
3. Nanoparticles: Coating

17. Some clothing manufacturers are making water and stain
repellent clothing using nano-sized whiskers in the fabric
that cause water to bead up on the surface.

18. ANTIMICROBIALFABRICS
• Nanohorizons, a company in Pennsylvania,
has started producing a silver nanoparticle
• material as both a dye and
• use in polyester and nylon.
• The silver nanoparticles are toxic to
microbes, and so colonies will never
form, and clothes using this material will
not have odors.
3. Nanoparticles

19. TITANIUM DIOXIDE PARTICLES IN OUR FOODS
Candies, sweets and chewing gum have been found to
contain the highest levels of titanium dioxide.
Powdered doughnuts, candies and gums with hard shells,
products with white icing and even bread, mayonnaise,
yogurt and other dairy products may also contain
titanium dioxide.
According to research published in Environmental
Science and Technology, up to 36 percent of the
titanium dioxide found in nearly 90 food products was
in the nanoparticle sizes.
TiO2 helps define colors clearly and can
prevent UV degradation (cracking and
breakdown of materials). You can find titanium
dioxide in food products like candy, coffee
creamer, baking and cake decorations, and white
sauces
3. Nanoparticles

21. SUNSCREENS
Zinc oxide and Titanium dioxide have
been used in sunscreens because of their
powerful UV blocking properties but they
leave a white coating on the skin, which
most people find unpleasant.
Many sunscreens and moisturizers
available now use these nanoparticles,
including products from;
Boots Avon
The Body Shop L'Oreal
Nivea
Unilever

22. • Catalysts
• Envirox™ cerium oxide
• Nanoremediation
• SAMMS technology to remove
mercury
• Paper
• photographic paper
• Filters
• nanofibres
• Toothpaste
• to remineralise teeth
• Food
• packaging
• Paint
• improved adhesion and anti-fungal
qualities/anti-graffiti
• Clothes
• non-staining and anti-radiation
• Batteries
• (Black & Decker) phosphate
nanocrystal technology
• Cleaning products
3. Nanoparticles

23. USES FOR CARS

24. DIFFERENT TYPES OF NANOMATERIALS
NANOMATERIALS CAN BE
DIVIDED INTO 4 TYPES:
1) CARBON-BASED
2) METAL-BASED
3) DENDRIMERS
4) COMPOSITES

25. Potential applications of carbon nanotubes
Materials & Chemistry
- Ceramic and metallic CNT composites
- Polymer CNT composites (heat conducting
polymers)
- Coatings (e.g. conductive surfaces)
- Membranes and catalysis
- Tips of Scanning Probe Microscopes (SPM)
Medicine & Life Science
- Medical diagnosis (e.g. Lab on a Chip (LOC))
- Medical applications (e.g. drug delivery)
- Chemical sensors
- Filters for water and food treatment
Electronics & ICT
- Lighting elements, CNT based field emission
displays
- Microelectronic: Single electron transistor
- Molecular computing and data storage
- Ultra-sensitive electromechanical sensors
- Micro-Electro-Mechanical Systems (MEMS)
Energy
- Hydrogen storage, energy storage (super
capacitors)
- Solar cells
- Fuel cells
- Superconductive materials

26. 2) METAL BASED NANOMATERIALS
These nanomaterials include
quantum dots, nanogold,
nanosilver and metal oxides,
such as titanium dioxide.
A quantum dot is a closely
packed semiconductor crystal
comprised of hundreds or
thousands of atoms, and
whose size is on the order of a
few nanometers to a few
hundred nanometers.
Changing the size of
quantum dots changes their
optical properties.

28. 3) DENDRIMERS
These nanomaterials are
nanosized polymers built from
branched units.
The surface of a dendrimer has
numerous chain ends, which can
be tailored to perform specific
chemical functions.
This property could also be useful
for catalysts, to help with chemical
reactions.
Also, because three- dimensional
dendrimers contain interior cavities
into which other molecules could
be placed, they may be useful for
drug delivery.

29. 4) COMPOSITES
Composites combine nanoparticles
with other nanoparticles or with
larger, bulk-type materials.
Clays and Polymers can be used to
make them.
Nanoparticles are already being
added to products ranging from
auto parts to packaging materials,
to enhance the following
properties:
Mechanical
Thermal
Barrier
Flame-retardance

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32. Why is there so much interest/concern about nanotechnology?
• Enormous potential
• Huge gaps in knowledge concerning the possible risks
• Difficulty in detecting and removing
• Absence of regulation

33. Potential Health Concerns
What are the Potentials risks associated with nanotechnology?
•Adverse health effects in humans from deliberate or accidental exposure
•Adverse effects on the environment from deliberate or accidental exposure
•Potentially explosive properties of nanostructures
•Cause for concern:
– Nanoparticles are similar in size to many biological structures  easily absorbed by the
body.
– Nanoparticles remain suspended in the environment for extended periods of time.
•Health Impacts of nanoparticles are expected to be dependant on composition
and structure.

34. Risk assessment problems
• Very difficult to detect without sophisticated equipment
• Difficult to predict how particles will behave in the environment (dispersed/clumped)
• Small size may result in particles passing into the body more easily (inhalation, ingestion,
absorption)
• May be more reactive due to surface area to volume ratio
• Potential to adsorb toxic chemicals
• Persistence - Longevity of particles in the environment and body are unknown