Emerging frontiers of nanoscience and nanotechnology

T. PradeepDepartment of Chemistry and Sophisticated Analytical Instrument Facility

Indian Institute of Technology MadrasChennai 600 036, India

Phone: 91-44-2257 4208 (direct) 2257 5938/5942 (lab and students)Fax: 91-44-2257 0545/0509/4202

http://www.dstuns.iitm.ac.in/prof-pradeep-group.php

Kalpakkam February 26, 2010

Alchemy

Nano

Lavoisier

Faraday

van’t Hoff Pauling

400+ papers

Electro-magnetic rotations (1821)

Benzene (1825)

Electro-magnetic induction (1831)

The laws of electrolysis and coining words such as electrode, cathode, ion (early 1830s)

The magneto-optical effect and diamagnetism (both 1845)

Field theory of electro-magnetism

Faraday’s gold preserved in Royal Institution. From the site, http://www.rigb.org/rimain/heritage/faradaypage.jsp

Nano 10-9

Number of papers published per year after the discovery of gold catalysis.

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

0

1000

2000

3000

4000

5000Nu

mbe r

of pu

blica

tion i

n gold

nano

parti

cle

Year

Publications per year as on December 31, 2009

With the key words, “gold” and “nanoparticle*”

Quantum

Growth of civilization reduced the size of objects manipulated

Technology is about manipulating objects

Objects for bulk technology – bulk materials.

An object for the nanotechnology - nanomaterials.

These solids are very different.They change the definition of disciplines!At the scale of nanometers, boundaries collapse!

Living tropical diatom x6000

http://www.ldeo.columbia.edu/res/fac/micro/images.section/pages/diatom4.gif

Disciplines converge!

Chemistry

Physics

Biology

Mathematics

Materials scienceEngineering sciences

Biotechnology

Pharmaceuticals

Medicine

Dis

tanc

e

Nano

Micro

Pico

Nanomaterials

A magnetotactic bacterium in TEM

Magnetospirillum magnetotacticum

Nature uses nanoparticles!

Proteins, DNA, enzymes,…….

Nanoparticles are formed in cells such as bacteria. Here gold particles are grown in buttermilk bacteria.

1000 nm500 nm

Magnetic nanoparticles

1 book = 300 pages = 300 x 300 words = 300 x 300 x 5 letters = 45,0000 letters

I library = 4.5 x 109 letters

The world knowledge = 100,000 libraries

=4.5 x 1014 letters

One letter in one nanoparticle.

=4.5 x 1017 atoms

(if 1 nanoparticle = 1000 atoms)

How big is that?

Not even a dust!

So, why do we need them?

Cluster size effects

Size dependent melting1871 Lord Kelvin asked “Does MP depend on size of the particle?”

1976, MP of gold was studied smallest gold melt at 300 K (Bulk 1336 K)

Variation in properties with size

Empirical scaling laws

General property, G(R) = G(∞) + a R-α Related to radiusG(R) = G(∞) + a N-β Related to number

G(R) is the property and G(∞) is the bulk limit

Ionization potential with size, K clusters.

This science is old.

Lycurgus cup; in transmitting light (left) and in reflected light (right). From the site, http://www.thebritishmuseum.ac.uk.

Silicon dioxide in Lycurgus cup = 73%Silicon dioxide in Modern Glass = 70%Sodium oxide in Lycurgus cup = 14%Sodium oxide in Modern Glass = 15%Calcium oxide in Lycurgus cup = 7%Calcium oxide in Modern Glass = 10%

So why is it coloured? The glass contains very small amounts of gold ( about 40 parts permillion) and silver ( about 300 parts per million)

R. P. Feynman“There’s plenty of room at the bottom”- http://www.zyvex.com/nanotech/feynman.html

“The principles of physics do not speak against the possibility of maneuvering things atom by atom”.

5 nm x 5 nm

Probe

Surface

Image showing atoms

Scanning probe microscopy. By scanning an atomically sharp probe over a surface, an atomically resolved image of the surface can be obtained.

H. Rohrer and G. Binnig, Nobel prize for physics 1986 for discovering STM.

Scanning tunneling microscopy (STM)

Local electronic structure

Image of 48 Fe atoms on a Cu (111) surface forming a Quantum corral, From the work of M. F. Crommie, C. P. Lutz and E. Eigler, Science, 262 (1993) 218.

A quantum corral with two foci. From, www.almaden.ibm.com/vis/stm/corral.html

5 nm x 5 nm

Probe

Surface Nano line drawn on the surface

Probe

Nanopatterns

A TEM and an image of a nanoparticle taken with TEM. The whole particle is of 4 nm in diamter and each point seen is an atom.

Atom

Particle

NSOM image of a human cell with nanoparticles inside.

Nano can be seen with light also!

Desorption electrospray mass spectrometry featured on the cover of the magazine, ‘Science’. The discoverer of the technique, Prof. R. G. Cooks is on the right.

Advances in other tools

The world we live: 2004

Population – 6.37 b (July 2004)Energy use – 14.93 (Trillion kWh electricity, 2001)Food – 1827 M tons (2003 estimate)

The world we live: 2050

Population – 10 bFood –Water –Air –

Why do we look at nano today?

Most challenging problems

EnergyWaterPopulation and associated issuesLandFood and agriculturePollutionBiodiversityWeaponsDiseasesNatural calamities

2000 1,838 1,855 -162001 1,870 1,898 -272002 1,819 1,910 -912003 1,827 1,932 -105

Food production and consumption in (Mtones)

World EnergyMillions of Barrels per Day (Oil Equivalent)

300

200

100

01860 1900 1940 1980 2020 2060 2100

Source: John F. Bookout (President of Shell USA) ,“Two Centuries of Fossil Fuel Ener International Geological Congress, Washington DC; July 10,1985. Episodes, vol 12, 257-262 (1989).

Solutions?

Nano is THE solutionAt least for some problems…

Can we reach there with our present knowledge?

Very new technologies are needed

Our common assumptions

Industrial development is a must to remove poverty. Millions must work in factories. Greater wealth means greater resource consumption. We must burn more fossil-fuels to have energy. Manufacturing means polluting. More advanced medicine will always be more expensive. Solar energy will never become really inexpensive. Toxic wastes cannot be eliminated. Developed land will never be returned to wilderness. There will never be weapons worse than nuclear missiles.

There will never be water in Chennai.

Summary

1. Industry as we know it cannot be replaced.

2. Technology as we know it will never be replaced

All wrong!We must look into history.

Eric Drexler and Chris Peterson,

Unbounding the Future: the Nanotechnology Revolution

The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote .. . Our future discoveries must be looked for in the sixth place of decimals.

Albert A. Michelson 1894

Where should we look at?

Nature Technology

New materials

Fullerenes discovered, 1985 Smalley, 1985

Cyanopolyynes

A sample of C60 solid (left) and its solution (right). 1990

Most researched single molecule!

Long molecule

Model of a Y-junction nanotube.

WS2 nanotube, scale 10 nm

R. Tenne

Gold metal (left), gold nanoparticle powder (middle) and its solution (right).

Clusters and magic numbers (13, 55, 147, 309, 561).

Gold shells. Nanoshells designed to absorb various wavelengths of light (the six vials on the right), including infrared (vial at far right) compared to gold colloid (far left). Used with permission from www.ece.rice.edu/people/faculty/halas.

TEM image of gold nanorods. An expanded view of the tip is on the left top corner.

A

20 nm

B

5 nm

CA

20 nm

B

5 nm

C

Gold nanotriangles

Quantum dots of CdSe showing fluorescence in different colours. From left to right, the particle size decreases. From, http://zqlin.public.iastate.edu/Pages/Homepage.htm

Nanotubes made of an inorganic oxide. Courtesy, Nature.

1988 1992 1996 2000 20040

4k

8k

12k

16k

Nano

* ref

eren

ces

Year

Nano publications

Applications

Nanotube-based materials. Nanotube (black) is woven with fibres to make super-tough clothing (left). Nanotube based spinning (right).

Novel properties

Nanotube-based TV screen developed by Samsung corporation.

Dye sensitized solar cells. Courtesy of Greatcell Solar.

Novel technologies for water, environment…

Carbon nanotube filters, membranes, nanopores…

Interaction of vancomycin with Au nanoparticles Bis(vancomycin) cystamide in water is reacted with 4 – 5 nm sized Au nanoparticles in toluene.

Au@van dissolves in the aqueous phase and can be seperated.

Nearly 31 Vancomycin molecules are bound on the surface of the Au nanoparticle as calculated from UV-Visible studies.

Control Experiment:-• Au@cys was prepared and nearly 1800 molecules of Cysteine was found to bind onto the nanoparticle surface.

• The broadness of the peak in UV-Vis studies indicated aggregation.

Delivery vehicles

Chem. Mater. 2003, 15, 20-28

Sensors

Temperature dependent clear-opaque transition of the thermosensitive gold nanoparticle

JACS 2004

Smart materials

Nanosensors of this kind can detect single molecules. http://www.kurzweilai.net/news/frame.html?main=news_single.html?id%3D2073

Single molecule detection

Carbon nanotube-based NEMS.

Nanoparticles of silver disappear in a chemical reaction.

Environmental protection

STM image of MoS2 nanoflakes. From, Nanotechnology 14, pp. 385-389 (2003)

Nanocatalysis

Applications

Endosulfan

Color changes with pesticide concentrationGood response at lower concentrationsDown to 0.1 ppmAdsorbed pesticides can be removed from solution

Color of gold nanoparticles with endosulfan

Endosulfan concentration in ppm

02100 200

Example

Pesticide removalIndian Patent grantedInternational patent filedTechnology commercialized, factory put up

J. Environ. Monitoring. 2003

Pesticide removal from drinking water

Indian patent grantedPCT application filedTechnology transferredProduct under testing and ready to launch

Time (minutes) Time (minutes)

A B

Inauguration

STM image of MoS2 nanoflakes. From, Nanotechnology 14, pp. 385-389 (2003)

Nanocatalysis

Pollutants Harmless products

ChlorocarbonsC2H2Cl2, C6Cl6, chlorpyrifos, endosulfan

amorphous carbon

TiO2

Polluted water Purified water

As adsorption

Magnetic Fe3O4 nanopartilcles

Purification by circulation

Magnetic separation

Magnetic clays for oil cleanupAntibody taggingMagnetic hyperthermia

Mind-matter?

Where are we heading to?

E. F. Schumacher

What do nanomaterials offer?

Carbon nanotubes are the toughest materials known.Nanoparticle based solar cells are more efficient than conventional ones.Nanoparticles of gold are highly efficient oxidation catalysts.Nanodots are very good fluorescent dyes.Nanotubes and particles can be delivered right into the cell nuclei.Nanoparticles find their way into our food and drugs.Nanoparticle based methods can screen diseases quickly.Many nanoparticles break toxic chemicals.……..

So what?

Our clothing will have nanomaterials tomorrow.Our toothpaste, soaps and detergents already have nanoparticles.Our medicines carry nanomaterials.Future surgeries will be done by needles and will be bloodless.Our world outside is going to change with new materials and systems. Mind and matter may be linked.

Let us look forward to that world…..Because ….

The great Indian realities

25,00,00,000 not have enough to eat That many with not enough clothing, housing, electricity,…80,00,00,000 with not enough water

We need 91,000,000 tons of grains per year to feed the hungry

Our roads, our environment, our forests, …

If we live the way we live….the neighbours will perish.

Something needs to be done.

And you must.

Confocal Raman Microscope

UltramicrotomeQTrap MS

Transmission Electron Microscope

MALDI TOF MS

Nano Mission, DST, Govt. of India

I thank my students and collaborators for their hard work which made it possible to stand before you…

Thank you all.