introduction to nanotechnology what is nanotechnology while many definitions for nanotechnology...

Introduction to Nanotechnology

What is Nanotechnology• While many definitions for nanotechnology exist, the

[National Nanotechnology Initiative] NNI calls it "nanotechnology" only if it involves all of the following:

1. Research and technology development at the atomic, molecular or macromolecular levels, in the length scale of approximately 1 - 100 nanometer range.

2. Creating and using structures, devices and systems that have novel properties and functions because of their small and/or intermediate size.

3. Ability to control or manipulate on the atomic scale.

Nanotechnology

• Is already making today’s products:– Lighter– Stronger – Faster– Smaller– More Durable

Understanding Size

How big (small) are we talking about?

Understanding Size

• 1 meter

source: CERN http://microcosm.web.cern.ch/microcosm

Understanding Size

• 10 centimeters


Understanding Size

• 1 centimeter


Understanding Size

• 100 micrometers


Understanding Size

• 10 micrometers


Understanding Size

• 1 micrometer


Understanding Size

• 100 nanometers


Understanding Size

• 10 nanometers


Understanding Size

• 1 nanometer


Size Matters

• It’s not just how big you are

• It’s what you can do with it

How small is Nano - small?

Units in nanometers (µm)

How small is nanotechnology?

Compared to Human Hair

A Human Hair is about 100,000µm wide

Nanotechnology spans many Areas

NANOTECHNOLOGY

InformationTechnology

Mechanical Eng. &

Robotics

Biotechnology

Transportation

NationalSecurity &Defense

Food andAgriculture

Energy &Environment

Aerospace

AdvanceMaterials &

Textiles

Medicine /

Health

NANOTECHNOLOGY


Mechanical Eng. &

Robotics

Biotechnology

Food andAgricultureAerospace

AdvanceMaterials &

Textiles

Medicine /

Health

Energy &Environment

NANOTECHNOLOGY


Mechanical Eng. &

Robotics

Biotechnology


AdvanceMaterials &

Textiles

Medicine /

Health

NANOTECHNOLOGY NationalSecurity &Defense

Food andAgriculture

Energy &Environment

Aerospace

AdvanceMaterials &

Textiles

Medicine /

Health

NANOTECHNOLOGY


AdvanceMaterials &

Textiles

Medicine /

Health

Energy &Environment

NANOTECHNOLOGY


Food andAgricultureAerospace Medicine

/Health

Mechanical Eng. &

Robotics


Food andAgriculture

Energy &Environment

Aerospace Medicine /

Health

NANOTECHNOLOGY


/Health

Energy &Environment

NANOTECHNOLOGY



/Health

BiotechnologyMechanical Eng. &

Robotics


Food andAgriculture

Energy &Environment


Health

NANOTECHNOLOGY


/Health

Energy &Environment

NANOTECHNOLOGY



/Health

Transportation


Robotics


Food andAgriculture

Energy &Environment


Health

NANOTECHNOLOGY


/Health



/Health


Mechanical Eng. &

Robotics



Robotics


Transportation


Robotics


NationalSecurity &Defense

Transportation

BiotechnologyMechanical Engineering /

Robotics


Key Dimensions in Nanometers

• An atom is about 0.3 nm in size.

• Typical spacing between 2 carbon atoms in a molecule is 0.12 – 0.15 nm.

• DNA double helix has a diameter of about 2 nm.

• A bacterium of the genus Mycoplasma has a length of 200 nm.

• A red blood cell is 6,000 nm in diameter.

• A human hair is 80,000 nm in diameter.

• To put this scale in context, the size of a nanometer to a meter, is the same as that of a marble to the size of the Earth.

Nanoscience would be boring if small things were just like big things.Nanoscience would be boring if small things were just like big things.Luckily they are not. Luckily they are not.

The color of gold changes with sizes The color of gold changes with sizes

The goal of nanoscience is to The goal of nanoscience is to find and understandfind and understandhow physical properties change with size.how physical properties change with size.

graphitegraphitebuckyballbuckyball nanotubenanotube

Graphite, for example, takes on interesting shapes if it is kept from becoming a Graphite, for example, takes on interesting shapes if it is kept from becoming a big solid.big solid.

Small things are different.

Properties of Nanoparticles• Materials reduced to the nano-scale can show

different properties compared to what they exhibit on the macro-scale.Opaque substances may become transparent

(copper); – stable materials turn combustible (aluminum); – insulators become conductors (silicon); and– solids turn to liquids at room temperature

(gold).

• Nanoparticles tend to be more chemically reactive than their ordinary sized counterparts because they have more surface area.

– An increase in surface area to volume ratio alters the mechanical, thermal, and catalytic properties of materials.

• Nanostructures or nanomaterials exhibit properties different from their macroscale counterparts (their “big brothers”) such as:– Mechanical strength (how hard they are to break)– Electrical conductivity (how fast electrons flow

through them)– Thermal conductivity (how fast heat flows through

them)– Chemical reactivity (how well/fast they react with

other chemicals)– Transparency (how well you can see through

them)– Magnetism (whether or not they are magnetic)– … and many more…

CLASSIFICATION OF NANOMATERIALS• Nanoparticles or nanospheres: (0-D) nanoscale lengths are

measured in all three dimensions• Nanotubes or nanowires or nanorods: (1-D) nanoscale lengths

are measured in two dimensions only• Nanoscale thin films or ultra-thin films: (2-D) nanoscale lengths

are measured in one dimension only• Nanocomposites: (3-D) a material comprised of many nanoscale

inclusions (such as nanoparticles)• Nanostructured materials: (3-D) a material that exhibits a

unique structure that can be measured at the nanoscale• Buckyballs: nanoparticles comprised of exactly 60 carbon atoms

(though there are other types), forming a network that resembles a soccer ball.

WHY DOES THIS HAPPEN?• Nanostructures obey the same fundamental laws of

the universe as everything else in nature• But… some things that are negligible (can be

ignored) at big scales cannot be ignored at small scales

• For example:– Imagine you are an electron moving through a

“big” copper wire 1 cm in diameter – you may never see the boundaries of the wire because you are so small compared to its diameter

– Imagine you are an electron moving through a “small” copper wire 1 nm in diameter (more comparable to the electron’s size) – now you bump into the boundaries of the wire often, which affects how you move through that wire

– Therefore, the 1 nm diameter copper wire exhibits different electrical properties than its macroscale counterpart!

1. Increase in Surface-to-Volume Ratio:

• Neglecting spaces between the smaller boxes, the volumes of the box on the left and the boxes on the right are the same but the surface area of the smaller boxes added together is much greater than the single box.

Single Box Ratio6 m2

1 m3 = 6 m2/m3

Smaller Boxes Ratio12 m2

1 m3 = 12 m2/m3

Another Way to Think of this Ratio Using Sugar Cubes

• Each individual cube is about 1 cm on a side, so each side has an area of 1 cm2. With six sides, it has a surface area of 6 cm2 and a volume of 1 cm3.

– This is a surface area to volume ratio of 6 cm2/cm3

• A block made from 64 sugar cubes is 4 cm on a side and has a surface area of 6 x 16 cm2 or 96 cm2 and a volume of 64 cm3.

– This is a surface area to volume ratio of 1.5 cm2/cm3.

• If you compute the surface of all 64 individual cubes, you would have 64 x 6cm2 or 384 cm2 or 4 times more surface area with the same total volume.

In small nanocrystals, the electronic energy levels are not continuous as in the bulk but are discrete (finite density of states), because of the confinement of the electronic wavefunction to the physical dimensions of the particles. This phenomenon is called quantum confinement and therefore nanocrystals are also referred to as quantum dots (QDs).

In any material, substantial variation of fundamental electrical and optical properties with reduced size will be observed when the energy spacing between the electronic levels exceeds the thermal energy (kT).

Moreover, nanocrystals possess a high surface area and a large fraction of the atoms in a nanocrystal are on its surface. Since this fraction depends largely on the size of the particle (30% for a 1-nm crystal, 15% for a 10-nm crystal), it can give rise to size effects in chemical and physical properties of the nanocrystal.

2. Quantum confinement

An Example of the Affects of Surface-to-Volume Ratios in Animals

• Larger surface-to-volume ratio– Very susceptible to changes in heat

• Smaller surface-to-volume ratio– Less susceptible to changes in heat

Nanoelectronics

StructuralApplications

Sensors,NEMSOrganic Inorganic

Bio

Nanomaterials Applications

and Related

• Nanocrystalline materials• Nanoparticles• Nanocapsules• Nanoporous materials• Nanofibers• Nanowires• Fullerenes• Nanotubes• Nanosprings• Nanobelts

• Molecular electronics• Quantum dots• NEMS, Nanofluidics• Nanophotonics, Nano-optics• Nanomagnetics• Nanofabrication• Nanolithography• Nanomanufacturing• Nanomedicine• Nano-bio

Top-down and Bottom-up Processes

Outline

• Top-down approach:• Bottom-up approach:

Top-Down Approach

• Uses the traditional methods to pattern a bulk wafer as in EE 418 lab.

• Is limited by the resolution of lithography.

http://pages.unibas.ch/phys-meso/Education/Projektstudien/Lithographie/Litho-M1-Lithography.html

What Constitutes a Top-down Process?

• Adding a layer of material over the entire wafer and patterning that layer through photolithography.

• Patterning bulk silicon by etching away certain areas.

www.nanoscience.at/ aboutnano_en.html

http://www.nanoscience.at/aboutnano_en.html

Current Top-down Technology

• Use of 193 excimer laser with phase shift masks to for features 65 nm in size.

• Phase shift masks and complex optics are used to achieve this resolution.

http://www.lrsm.upenn.edu/~frenchrh/lithography.htm

193 nm ArF excimer laser photolithography stepper

Bottom-Up Approach

• The opposite of the top-down approach.

• Instead of taking material away to make structures, the bottom-up approach selectively adds atoms to create structures.

http://idol.union.edu/~malekis/ESC24/KoskywebModules/sa_topd.htm

The Ideas Behind the Bottom-up Approach

• Nature uses the bottom up approach.– Cells– Crystals– Humans

• Chemistry and biology can help to assemble and control growth.

Top-down Versus Bottom-up

Etched wafer with desired pattern

Apply layer of photoresist

Expose wafer with UV light through mask and

etch wafer

Start with bulk wafer

Top Down Process Bottom Up Process

Start with bulk wafer

Alter area of wafer where structure is to be created by

adding polymer or seed crystals or other

techniques.

Grow or assemble the structure on the area

determined by the seed crystals or polymer. (self

assembly)

Similar results can be obtained through bottom-up and top-down processes

Material Processing by Sol-Gel Method

IntroductionThe sol-gel process is very long known since the late 1800s. The versatility of the technique has been rediscovered in the early 1970s when glasses where produced without high temperature melting processes. This made possible the organic modification of silicon compounds (ORMOSIL), which cannot withstand high temperatures. Sol-gel is a chemical solution process used to make ceramic and glass materials in the form of thin films, fibers , or powders . A sol is a colloidal (the dispersed phase is so small that gravitational forces do not exist; only Van der Waals forces and surface charges are present) or molecular suspension of solid particles of ions in a solvent. A gel is a semi-rigid mass that forms when the solvent from the sol begins to evaporate and the particles or ions left behind begin to join together in a continuous network

Formation of a metal oxide involves connecting the metal centers with oxo (M-O-M) or hydroxo (M-OH-M) bridges, therefore generating metal-oxo or metal-hydroxo polymers in solution. The drying process serves to remove the liquid phase from the gel thus forming a porous material, then a thermal treatment (firing) may be performed in order to favor further polycondensation and enhance mechanical properties.

In essence, the sol-gel process usually consists of 4 steps:(1) The desired colloidal particles once dispersed in a liquid to form a sol.(2) The deposition of sol solution produces the coatings on the substrates by spraying, dipping or spinning.(3) The particles in sol are polymerized through the removal of the stabilizing components and produce a gel in a state of a continuous network.(4) The final heat treatments pyrolyze the remaining organic or inorganic components and form an amorphous or crystalline coating.

The sol-gel approach is interesting in that it is a cheap and low-temperature technique that allows for the fine control on the product’s chemical composition as even small quantities of dopants, such as organic dyes and rare earth metals, can be introduced in the sol and end up in the final product finely dispersed. An overview of the sol-gel process is presented in a simple graphic work below.

Sol-Gel process overview:

Advantages of Sol-Gel Technique:

Can produce thin bond-coating to provide excellent adhesion between the metallic substrate and the top coat.Can produce thick coating to provide corrosion protection performance.Can easily shape materials into complex geometries in a gel state.Can produce high purity products because the organo-metallic precursor of the desired ceramic oxides can be mixed, dissolved in a specified solvent and hydrolyzed into a sol, and subsequently a gel, the composition can be highly controllable.Can have low temperature sintering capability, usually 200-600°C.Can provide a simple, economic and effective method to produce high quality coatings.

Applications:

It can be used in ceramics manufacturing processes, as an investment casting material, or as a means of producing very thin films of metal oxides for various purposes.

Other elements (metals, metal oxides) can be easily incorporated into the final product and the silicalite sol formed by this method is very stable.

Other products fabricated with this process include various ceramic membranes for microfiltration, ultrafiltration, nanofiltration, pervaporation and reverse osmosis.

http://en.wikipedia.org/wiki/Ceramic

http://en.wikipedia.org/wiki/Investment_casting

http://en.wikipedia.org/wiki/Thin_film

http://en.wikipedia.org/wiki/Oxide

http://en.wikipedia.org/wiki/Artificial_membrane

http://en.wikipedia.org/wiki/Microfiltration

http://en.wikipedia.org/wiki/Ultrafiltration

http://en.wikipedia.org/wiki/Nanofiltration

http://en.wikipedia.org/wiki/Pervaporation

Chemical Vapour Deposition :Introduction

Chemical vapour deposition or CVD is a generic name for a group of processes that involve depositing a solid material from a gaseous phase.Microfabrication processes widely use CVD to deposit materials in various forms, including: monocrystalline, polycrystalline, amorphous, and epitaxial. These materials include: silicon, carbon fiber, carbon nanofibers, filaments, carbon nanotubes, SiO2, silicon-germanium, tungsten, silicon carbide, silicon nitride, silicon oxynitride and titanium nitride. CVD process is also used to produce synthetic diamonds.

50

Working Concept• 1. A material, often a metal, is evaporated from a heated

metallic source into a chamber which has been previously evacuated to about 10–7torrand backfilled with inert gas to a low-pressure.

• 2. The metal vapor cools through collisions with the inert gas atoms, becomes supersaturated and then nucleates homogeneously; the particle size is usually in the range 1–100 nm and can be controlled by varying the inert gas pressure.

• 3. Ultimately, the particles are collected and may be compacted to produce a dense nanomaterial.

• A simplified concept diagram is shown as Fig • Metal deposition metal halide (g) → metal(s) + byproduct (g)• Ceramic deposition metal halide (g) + oxygen/carbon/nitrogen/boron source

(g) → ceramic(s) + byproduct (g) g- gas; s-solid 51

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CVD REACTION

During the process of chemical vapor deposition, the reactant gases not only react with the substrate material at the wafer surface (or very close to it), but also in gas phase in the reactor's atmosphere. Reactions that take place at the substrate surface are known as heterogeneous reactions, and are selectively occurring on the heated surface of the wafer where they create good-quality films. Reactions that take place in the gas phase are known as homogeneous reactions. Homogeneous reactions form gas phase aggregates of the depositing material, which adhere to the surface poorly and at the same time form low-density films with lots of defects. In short, heterogeneous reactions are much more desirable than homogeneous reactions during chemical vapor deposition.

UNIT IV LECTURE 3 53

A typical CVD system consists of the following parts: sources of and feed lines for gases; mass flow controllers for metering the gases into the system; a reaction chamber or reactor; a system for heating up the wafer on which the film is to be deposited; and temperature sensors.

UNIT IV LECTURE 3 54

Applications• CVD processes are used on a surprisingly wide range of

industrial components, from aircraft and land gas turbine blades, timing chain pins for the automotive industry, radiant grills for gas cookers and items of chemical plant, to resist various attacks by carbon, oxygen and sulphur.

• Some important applications are listed below.• Surface modification to prevent or promote adhesion • Photoresist adhesion for semiconductor wafers Silane/substrate

adhesion for microarrays (DNA, gene, protein, antibody, tissue) • MEMS coating to reduce stiction • BioMEMS and biosensor coating to reduce "drift" in device

performance• Promote biocompatibility between natural and synthetic

materials Copper capping Anti-corrosive coating

Properties of Carbon Nanotubes• Stronger than steel• Multiple tubes slide inside

of each other with minimal effects of friction.

• Electrical current density 1000 times greater than silver or copper.

• Can range from having metallic properties to semiconductor properties based on it’s configuration.

http://en.wikipedia.org/wiki/Nanotubes

Types of Carbon Nanotubes

metallic

http://www.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p24.html

Semimetallic and semiconducting

Advancements Made so Far

• Carbon nanotube transistor (Stanford U.)

• Organic monolayers for organic transistor (Yale U.)

• Nanotube based circuit constructed (IBM)

• Nanomotors and gears created (NASA)

http://snf.stanford.edu/Education/Nanotechnology.SNF.ppt

Targeted Drug Delivery

05 March. 2011 M S Ramaiah Institute of Technology, Bangalore 59

05 March. 2011 60M S Ramaiah Institute of Technology, Bangalore

Nanotechnology – based drug delivery Systems

PastShared computing thousands of people sharing a mainframe computer

PresentPersonal computing

FutureUbiquitous computing thousands of computers sharing each and everyone of us; computers embedded in walls, chairs, clothing, light switches, cars….; characterized by the connection of things inthe world with computation.

• More efficient catalytic converters

• Thermal barrier and wear resistant coatings

• Battery, fuel cell technology

• Improved displays

• Wear-resistant tires

• High temperature sensors for ‘under the hood’; novel sensors for “all-electric” vehicles

• High strength, light weight composites for increasing fuelefficiency

Products Currently on the Market Using Nanotechnology

• Over 600 nanotech enabled products are on the market today. Some examples are:

– Carbon nanotubes in bike frames and tennis rackets make the products stronger and lighter This bike frame weights 2.75 pounds

• Nano-size particles of titanium dioxide and zinc oxide are less visible than the whitish particles of the older sunscreens. They block UV light more effectively without turning your skin white

– Older sunscreen leaves a white sheen behind

• Self cleaning glass uses UV light to energize nanoparticles to break down and loosen dirt on glass. Particles are also hydrophilic so water spreads across the glass evenly and helps wash the glass clean.

• Coating fabric with nanoparticles helps repel the water and other materials to make clothes stain resistant.

• Nanoparticles of silver in antimicrobial bandages block the microbes cellular respiration, thus killing them.

• Nanoparticles in scratch resistant coatings are common on everything from cars to eyeglass lenses.

• Bridgestone engineers developed a Quick Response Liquid Powder Display, a flexible digital screen, using nanotechnology.

Nanofibers:What are they? Why are they important?

SOME CURRENT APPLICATIONS OF

NANOTECHNOLOGY

SOLAR CELLSNanotechnology enhancements provide:

Improved efficiencies: novel nanomaterials can harness more of the sun’s energy

Lower costs: some novel nanomaterials can be made cheaper than alternatives

Flexibility: thin film flexible polymers can be manipulated to generate electricity from the sun’s energy

COMPUTINGNanotechnology enhancements provide:

Faster processing speeds: miniaturization allows more transistors to be packed on a computer chip

More memory: nanosized features on memory chips allow more information to be stored

Thermal management solutions for electronics: novel carbon-based nanomaterials carry away heat generated by sensitive electronics

CLOTHINGNanotechnology enhancements provide:

Anti-odor properties: silver nanoparticles embedded in textiles kill odor causing bacteria

Stain-resistance: nanofiber coatings on textiles stop liquids from penetrating

Moisture control: novel nanomaterials on fabrics absorb perspiration and wick it away

UV protection: titanium nanoparticles embedded in textiles inhibit UV rays from penetrating through fabric

BATTERIESNanotechnology enhancements provide: Higher energy storage capacity and quicker recharge:

nanoparticles or nanotubes on electrodes provide high surface area and allow more current to flow

Longer life: nanoparticles on electrodes prevent electrolytes from degrading so batteries can be recharged over and over

A safer alternative: novel nano-enhanced electrodes can be less flammable, costly and toxic than conventional electrodes

SPORTING GOODS AND EQUIPMENTNanotechnology enhancements provide: Increased strength of materials:

novel carbon nanofiber or nanotube-based nanocomposites give the player a stronger swing

Lighter weight materials: nanocomposites are typically lighter weight than their macroscale counterparts

More “perfect” fabrication of materials: controlling material characteristics at the nanoscale helps ensure that a ball flies in the direction of applied force and/or reduces the chance for fracture of equipment

CARSNanotechnology enhancements provide: Increased strength of materials:

novel carbon nanofiber or nanotube nanocomposites are used in car bumpers, cargo liners and as step-assists for vans

Lighter weight materials: lightweight nanocomposites mean less fuel is used to make the car go

Control of surface characteristics: nanoscale thin films can be applied for optical control of glass, water repellency of windshields and to repair of nicks/scratches

FOOD AND BEVERAGENanotechnology enhancements provide: Better, more environmentally

friendly adhesives for fast food containers: biopolymer nanospheres instantly tack surfaces together

Anti-bacterial properties: Nano silver coatings on kitchen tools and counter-tops kill bacteria/microbes

Improved barrier properties for carbonated beverages or packaged foods: nanocomposites slow down the flow of gas or water vapor across the container, increasing shelf life

THE ENVIRONMENTNanotechnology enhancements provide: Improved ability to capture

groundwater contaminants: nanoparticles with high surface area are injected into groundwater to bond with contaminants

Replacements for toxic or scarce materials: novel nanomaterials can be engineered to exhibit specific properties that mimic other less desirable materials

DRUG DELIVERYNanotechnology enhancements will provide:

New vehicles for delivery: nanoparticles such as buckyballs or other cage-like structures that carry drugs through the body

Targeted delivery: nano vehicles that deliver drugs to specific locations in body

Time release: nanostructured material that store medicine in nanosized pockets that release small amounts of drugs over time

CANCERNanotechnology enhancements will provide:

Earlier detection: specialized nanoparticles that target cancer cells only – these nanoparticles can be easily imaged to find small tumors

Improved treatments: infrared light that shines on the body is absorbed by the specialized nanoparticles in the cancer cells only, leading to an increased localized temperature that selectively kills the cancer cells but leaves normal cells unharmed

MOLECULAR MANUFACTURING

Nanotechnology enhancements will provide: Ability to build structures,

materials, devices and systems from the “bottom-up” atom by atom or molecule by molecule

“Nanobots” or “nanomachines” that can position atoms or molecules to build with atomic accuracy

Zero to little waste because atoms are placed exactly where they should go

SENSORSNanotechnology enhancements will provide: Higher sensitivity: high surface area of

nanostructures that allows for easier detection of chemicals, biological toxins, radiation, disease, etc.

Miniaturization: nanoscale fabrication methods that can be used to make smaller sensors that can be hidden and integrated into various objects

NEXT GENERATION COMPUTING (QUANTUM, DNA, MOLECULAR)

Nanotechnology enhancements will provide: The ability to control atomic scale

phenomena: quantum or molecular phenomena that can be used to represent data

Faster processing speeds Lighter weight and miniaturized

computers Increased memory Lower energy consumption

NANOROBOTICSNanotechnology enhancements will provide: Miniaturized fabrication of

complex nanoscale systems: nanorobots that propel through the body and detect/ cure disease or clandestinely enter enemy territory for a specific task

Manipulation of tools at very small scales: nanorobots that help doctors perform sensitive surgeries

WATER PURIFICATIONNanotechnology enhancements will provide:

Easier contamination removal: filters made of nanofibers that can remove small contaminants

Improved desalination methods: nanoparticle or nanotube membranes that allow only pure water to pass through

Lower costs Lower energy use

Applications of Nanotechnology

Are there nanoparticles in nature?Natural nanoparticles also exist. For example:

Nanotechnology scientists try to copy natural nanoparticles to make new materials that are useful.

Insects and lizards are able to stick to walls because of the nanostructures on their feet.

Butterflies’ wings contain shiny reflective nanocrystals.

Spiders’ webs are made of super-strong nanofibres.

Chloroplasts in plant cells are nanofactories that harness the Sun’s energy to make glucose.

Nano-structured surfaces can have peculiar wetting properties→ Interplay of chemistry and nano-topography: superhydrophobic effect→ Superhydrophobicity is found in Nature (Lotus Effect®)→ Scientists are engineering materials to be superhydrophobic and require less cleaning→Applications Solar panels Textiles Coatings

Experiment D- Superhydrophobic MaterialsApplications of Nanotechnologies: Environment

The Lotus effectThe Lotus plant (Nelumbo Nucifera) is a native Asian plant

which has the distinct property of having its leaves particularly clean even if its natural habitat is muddy.

The leaves of the Lotus plant have the outstanding characteristic of totally repelling water because they are superhydrophobic. → Droplets of water on the lotus leaf appear spherical like beads. → When you splash the Lotus leaf with water, water rolls off the leaf, and in doing so drags dirt away.→ The result is that the Lotus leaf is dry and clean. → The surface of the Lotus leaf self-cleans. This is called the Lotus Effect®.→ The same effect is seen in Nasturtium.→ Watch Video 3_ Lotus Effect® (Part 1)

Carbon based nano structures

Session VI, Slide 88

Bucky ball Carbon nano tube

http://www.nccr-nano.org/nccr/media/gallery/gallery_01/gallery_01_03

Session VI, Slide 89

Why Nano Gold Particles?

The optical applications of nano materials

Nanoparticles also interact differently with light.

Normally, gold metal appears gold in colour. However, nanoparticles of gold in solution appear red and blue in colour.

Different-sized nanoparticles of gold give different coloured solutions.

Smaller nanoparticles appear red in solution, while slightly larger nanoparticles appearblue.

Using nanoparticles – cleaningNanoparticles can also help to keep things clean. Could dirty football shirts be a thing of the past?

Fabrics have been developed with nano-coatings, which repel liquid and resist stains.

Windows that are self-cleaning have been developed by British scientists. How could self-cleaning windows work?

Spillages on treated fabrics will not soak into the fabric, but form beads of liquid, which can simply be wiped away.

Using nanoparticles – glass

Future Applications

• 2011-15 -- nanobiomaterials, microprocessors, new catalysts, portable energy cells, solar cells, tissue/organ regeneration, smart implants

• 2016 and beyond – molecular circuitry, quantum computing, new materials, fast chemical analyses

Keep learning. Learn more about the computer, crafts, gardening, whatever... Never let the brain idle. 'An idle mind is the devil's workshop.' And the devil's name is Alzheimer's.

Enjoy the simple things.

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E-mail: [email protected]

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