Collapsing boundaries at the nanoscale

Transcription

1 Collapsing boundaries at the nanoscale T. Pradeep Department of Chemistry and Sophisticated Analytical Instrument Facility Indian Institute of Technology Madras Chennai , India The School, Chennai September 16, 2008

2 Nano van t Hoff Pauling Lavoisier Faraday Alchemy

3 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 400+ papers

4 Faraday s gold preserved in Royal Institution. From the site,

5 -9 Nanosecond, nanojoule, nanocalory, nanovolt, nanoampere,.

6 442 m 1 μm

7 Quantum

8 Particle or wave? Gravity Quantum Gene Nano Steam engine Factories Transistor Viagra

9 Technology is about manipulating objects Growth of civilization reduced the size of objects manipulated

10 Objects for bulk technology bulk materials.

11 An object for the nanotechnology - nanomaterials.

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13 Molecule Nanoparticle core Schematic of a nanoparticle.

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

15 Living tropical diatom x6000

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17 Physics Biotechnology Engineering sciences Chemistry Biology Materials science Pharmaceuticals Mathematics Medicine Disciplines converge!

18 Nature uses nanoparticles! A magnetotactic bacterium in TEM Magnetospirillum magnetotacticum Proteins, DNA, enzymes,.

19 1000 nm 500 nm Nanoparticles are formed in cells such as bacteria. Here gold particles are grown in buttermilk bacteria.

20 So, why do we need them? 1 book = 300 pages = 300 x 300 words = 300 x 300 x 5 letters = 45,0000 letters I library = 4.5 x 10 9 letters The world knowledge = 100,000 libraries =4.5 x letters One letter in one nanoparticle. =4.5 x atoms (if 1 nanoparticle = 1000 atoms) How big is that? Not even a dust! Magnetic nanoparticles

21 Cluster size effects Size dependent melting 1871 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 Ionization potential with size, K clusters. General property, G(R) = G( ) + a R -α G(R) = G( ) + a N -β Related to radius Related to number G(R) is the property and G( ) is the bulk limit

22 This science is old.

23 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 per million) and silver ( about 300 parts per million) Lycurgus cup; in transmitting light (left) and in reflected light (right). From the site,

24 R. P. Feynman There s plenty of room at the bottom - The principles of physics do not speak against the possibility of maneuvering things atom by atom.

25 Image showing atoms Probe Surface 5 nm x 5 nm Scanning probe microscopy. By scanning an atomically sharp probe over a surface, an atomically resolved image of the surface can be obtained.

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

27 Scanning tunneling microscopy (STM)

28 Local electronic structure

29 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.

30 A quantum corral with two foci. From,

31 Nanopatterns Probe Probe 5 nm x 5 nm Surface Nano line drawn on the surface

32 Atom Particle 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.

33 Nano can be seen with light also! NSOM image of a human cell with nanoparticles inside.

34 Advances in other tools 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.

35 Why do we look at nano today? The world we live: 2004 The world we live: 2050 Population 10 b Food Water Air Population 6.37 b (July 2004) Energy use (Trillion kwh electricity, 2001) Food 1827 M tons (2003 estimate)

36 Most challenging problems Energy Water Population and associated issues Land Food and agriculture Pollution Biodiversity Weapons Diseases Natural calamities

37 Food production and consumption in (Mtones) ,838 1, ,870 1, ,819 1, ,827 1,

38 World Energy Millions of Barrels per Day (Oil Equivalent) 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, (1989).

39 Solutions?

40 Nano is THE solution At least for some problems Can we reach there with our present knowledge?

41 Very new technologies are needed

42 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.

43 Summary 1. Industry as we know it cannot be replaced. 2. Technology as we know it will never be replaced

44 All wrong! We must look into history. Eric Drexler and Chris Peterson, Unbounding the Future: the Nanotechnology Revolution

45 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

46 Where should we look at?

47 Nature Technology

48 New materials

49 Smalley, 1985 Fullerenes discovered, 1985 Cyanopolyynes

50 A sample of C 60 solid (left) and its solution (right) Most researched single molecule!

51 Long molecule

52 Model of a Y-junction nanotube.

53 WS 2 nanotube, scale 10 nm R. Tenne

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

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

57 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

58 A B C 20 nm 5 nm TEM image of gold nanorods. An expanded view of the tip is on the left top corner.

59 Gold nanotriangles

60 Quantum dots of CdSe showing fluorescence in different colours. From left to right, the particle size decreases. From,

61 Nanotubes made of an inorganic oxide. Courtesy, Nature.

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63 16k Nano* references 12k 8k 4k Year Nano publications

64 Applications

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

66 Novel properties

67 Nanotube-based TV screen developed by Samsung corporation.

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69 Dye sensitized solar cells. Courtesy of Greatcell Solar.

70 Novel technologies for water, environment Carbon nanotube filters, membranes, nanopores

71 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:- Delivery vehicles 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.

72 Sensors Chem. Mater. 2003, 15, 20-28

73 Smart materials Temperature dependent clear-opaque transition of the thermosensitive gold nanoparticle JACS 2004

74 Single molecule detection Nanosensors of this kind can detect single molecules.

75 Carbon nanotube-based NEMS.

76 Environmental protection Nanoparticles of silver disappear in a chemical reaction.

77 Nanocatalysis STM image of MoS 2 nanoflakes. From, Nanotechnology 14, pp (2003)

78 Applications Color of gold nanoparticles with endosulfan Example Endosulfan Endosulfan concentration in ppm Color changes with pesticide concentration Pesticide removal Good response at lower concentrations Indian Patent granted Down to 0.1 ppm International patent filed Adsorbed pesticides can be removed from solution Technology commercialized, factory put up 2 0 J. Environ. Monitoring. 2003

79 Pesticide removal from drinking water A B Time (minutes) Time (minutes) Indian patent granted PCT application filed Technology transferred Product under testing and ready to launch

80 Inauguration

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82 Nanocatalysis STM image of MoS 2 nanoflakes. From, Nanotechnology 14, pp (2003)

83 Pollutants Harmless products TiO 2 Chlorocarbons C 2 H 2 Cl 2, C 6 Cl 6, chlorpyrifos, endosulfan amorphous carbon

84 Polluted water Purified water

85 As adsorption Magnetic Fe 3 O 4 nanopartilcles Purification by circulation

86 Magnetic separation Magnetic clays for oil cleanup Antibody tagging Magnetic hyperthermia

87 Molecular nanomachines Bead Stopper Stopper Station 1 Station 2 [2] rotaxane A nano motion device. Bead going from station 1 to station 2 will make a molecular shuttle.

88 E. F. Schumacher

89 Where are we heading to? Mind-matter?

90 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.

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

92 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 And you must. Our roads, our environment, our forests, If we live the way we live.the neighbours will perish. Something needs to be done.

93 I thank my students and collaborators for their hard work which made it possible to stand before you Thank you all.

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98 Confocal Raman Microscope MALDI TOF MS Transmission Electron Microscope QTrap MS Nanoscience and Nanotechnology Initiative of the DST Ultramicrotome