Nano

Slow-Releasing NanoburrsFrom herbal tea

Honeybee's two compound eyes

Up Close With Your Tongue

Sugar

Single layer of graphene

Pollen

What's Measured Gets Managed.

What do you measure?

FNI 1B 12

Common Unit Conversions used in Nanoscience

1 m = 100 cm1 m = 1,000 mm1 m = 1,000,000 μm = 106 μm 1 m = 1,000,000,000 nm = 109 nm1 m = 10,000,000,000 Å = 1010 Å1 cm = 107 nm1 cm = 108 Å1 mm = 1,000 μm1 μm = 1,000 nm1 μm = 10,000 Å

nm – measure atomic structureÅ – measure light waves

One nanometer =3 silicon atoms in a row

1 millimeter = 1,000,000 nanometers

15,000,000

2cm nm

1,000,000 nanometers

cm

inches

IBM logo made up of 35 atoms of xenon on nickel17 nanometres long and was made with a scanning tunnelling microscope in 1986

Spider’s Skin

Human Hair with Lice

The tree-like structures in this scanning electron microscope image of a cross section of a butterfly wing are on the undersides of the Morpho's wing scale ridges. These microribs reflect light to create iridescent colors. The Blue Morpho is common in Central and South America and known for its bright blue wings. However, these iridescent colors are created not by pigments in the wing tissues but instead by the way light interacts with nanometer-sized structures on the Morpho's wing scales. This effect is being studied as a model in the development of new fabrics, dye-free paints, and anti-counterfeit technologies for currency.

Structure of butterfly wing

Based on this discovery of butterflies wing structure, engineers are developing single sensors that are tailored to detect certain types of chemical agents or explosives. These sensors light up when they encounter threats.

Small, smaller, "nano" data storage!

Metallofullerene Model 80 carbon atoms (light blue) 3 dysprosium atoms (red) 1 nitrogen atom (dark blue)

Small, smaller, "nano" transport of very small

Nanotube

T4 Bacteriophage - a virus

Your Brain1. There are approximately 50,000,000 neurons per square centimeter (50X106 per cm3)2. Each cm3 neurons have axons that reach out to create 1 trillion synapse (1×1012)

3. If each synapse can express 8 bits or 1 byte of information, than 1 cm3 contains 1 terabyte of data (1×1012)

4. The human brain is roughly 1000 cm3 in size which means it can store about 1 petabyte of data (1×1015)

5. That is about 1/3 as much data as stored in the entire internet … in one average human brain.

So when will a computer the size of a brain match its capacity? By current rates of change it looks like we will be there between 2025 and 2030.

Brain Cell – Soma and Dendrites

Snail neuron grown on a chip that records the neuron’s activity

Properties of a Material• A property describes how a material acts

under certain conditions• Types of properties– Optical (e.g. color, transparency)– Electrical (e.g. conductivity)– Physical (e.g. hardness, melting point)– Chemical (e.g. reactivity, reaction rates)

• Properties are usually measured by looking at large (~1023) aggregations of atoms or molecules

32Sources: http://www.bc.pitt.edu/prism/prism-logo.gifhttp://www.physics.umd.edu/lecdem/outreach/QOTW/pics/k3-06.gif

Optical Properties Change: Color of Gold

• Bulk gold appears yellow in color• Nanosized gold appears red in color– The particles are so small that electrons are not

free to move about as in bulk gold– Because this movement is restricted, the

particles react differently with light

33Sources: http://www.sharps-jewellers.co.uk/rings/images/bien-hccncsq5.jpghttp://www.foresight.org/Conferences/MNT7/Abstracts/Levi/

12 nanometer gold clusters of particles look red

“Bulk” gold looks yellow

Electrical Properties Change: Conductivity of Nanotubes

• Nanotubes - long, thin cylinders of carbon– 100 times stronger than steel, very flexible,– unique electrical properties

• Their electrical properties change with diameter, “twist”, and number of walls– either conducting or semi-conducting in their electrical

behavior

34Source: http://www.weizmann.ac.il/chemphys/kral/nano2.jpg

Electric current varies

by tube structure

Multi-walled

Physical Properties Change:Melting Point of a Substance

• Melting Point (Microscopic Definition)– Temperature at which the atoms, ions, or

molecules in a substance have enough energy to overcome the intermolecular forces that hold the them in a “fixed” position in a solid

35Sources: http://puffernet.tripod.com/thermometer.jpg and image adapted from http://serc.carleton.edu/usingdata/nasaimages/index4.html

In contact with 3 atoms

In contact with 7 atoms

Surface atoms require less energy to move because they are in contact with fewer atoms of the substance

Physical Properties Example:Substance’s Melting Point II

At the macroscale

At the nanoscale

The majority of the atoms are…

…almost all on the inside of the object

…split between the inside and the surface of the object

Changing an object’s size…

…has a very small effect on the percentage of atoms on the surface

…has a big effect on the percentage of atoms on the surface

The melting point…

…doesn’t depend on size

… is lower for smaller particles36

Size Dependant Properties

Why do properties change?

37

Scale Changes Everything

• There are enormous scale differences in our universe!

• At different scales– Different forces

dominate – Different models

better explain phenomena

38

Scale Changes Everything II

• Four important ways in which nanoscale materials may differ from macroscale materials– Gravitational forces become negligible and

electromagnetic forces dominate– Quantum mechanics is the model used to describe

motion and energy instead of the classical mechanics model

– Greater surface to volume ratios– Random molecular motion becomes more

important39

Dominance of Electromagnetic Forces

• Because the mass of nanoscale objects is so small, gravity becomes negligible

40

– Gravitational force is a function of mass and distance and is weak between (low-mass) nanosized particles

– Electromagnetic force is a function of charge and distance is not affected by mass, so it can be very strong even when we have nanosized particles

– The electromagnetic force between two protons is 1036 times stronger than the gravitational force!

Sources: http://www.physics.hku.hk/~nature/CD/regular_e/lectures/images/chap04/newtonlaw.jpghttp://www.antonine-education.co.uk/Physics_AS/Module_1/Topic_5/em_force.jpg

Quantum Effects

• Classical mechanical models that we use to understand matter at the macroscale break down for…– The very small (nanoscale)– The very fast (near the speed of light)

• Quantum mechanics better describes phenomena that classical physics cannot, like…– The colors of nanogold– The probability (instead of certainty) of

where an electron will be found41

Macrogold

Sources: http://www.phys.ufl.edu/~tschoy/photos/CherryBlossom/CherryBlossom.htmlhttp://www.nbi.dk/~pmhansen/gold_trap.ht; http://www.sharps-jewellers.co.uk/rings/images/bien-hccncsq5.jpg;

Nanogold

Surface to Volume Ratio Increases

• As surface to volume ratio increases – A greater amount of a

substance comes in contact with surrounding material

– This results in better catalysts, since a greater proportion ofthe material is exposed for potential reaction

42Source: http://www.uwgb.edu/dutchs/GRAPHIC0/GEOMORPH/SurfaceVol0.gif

Random Molecular Motion is Significant

• Tiny particles (like dust) move about randomly– At the macroscale, we barely see

movement, or why it moves– At the nanoscale, the particle is

moving wildly, batted about by smaller particles

43Source: http://www.ap.stmarys.ca/demos/content/thermodynamics/brownian_motion/rand_path.gif

• Analogy– Imagine a huge (10 meter) balloon being batted

about by the crowd in a stadium. From an airplane, you barely see movement or people hitting it; close up you see the balloon moving wildly.