NANO

matter is composed of discrete entities called atoms. Feynman in his 1960 article 'There's plenty of room at the bottom' Nano materials are found in both biological systems and man-made structures

Nature has been using nano materials for millions of years. As Dickson has noted 'Life itself could be regarded as a nanophase system.‘ Examples in which nano structured elements play a vital role are magnetotactic bacteria , ferritin , and molluscan teeth .

Several species of aquatic bacteria use the Earth's magnetic field to orient themselves. They are able to do this because they contain chains of nanosized, single-domain magnetite (Fe3O4 )particles. Because they have established their orientation, they are able to swim down to nutriments and away from what is lethal to them, oxygen.

Another example of nano materials in nature is the storage of iron in a bioavailable form within the 8 nm protein cavity of ferritin Some consider biological nanomaterials as model systems for developing technologically useful nanomaterials  

Scientific work on this subject can be traced back over 100 years. In 1861 the British chemist Thomas Graham coined the term colloid to describe a solution containing 1 to 100 nm diameter particles in suspension Around the turn of the century, such famous scientists as Rayleigh, Maxwell, and Einstein studied colloids

In 1930 the Langmuir–Blodgett method for developing monolayer films was developed. By 1960 Uyeda had used electron microscopy and diffraction to study individual particles. At about the same time arc, plasma, and chemical flame furnaces were employed to produce submicron particles.

Magnetic alloy particles for use in magnetic tapes were produced in 1970. By 1980, studies were made of clusters containing fewer than 100 atoms. In 1985, a team led by Smalley and Kroto found spectroscopic evidence that C60 clusters were unusually stable. In 1991, Iijima reported studies of graphitic carbon tube filaments.

Research on nano materials has been stimulated by their technological applications. The first technological use of these materials were as catalysts and pigments

What is nano technology It is the collaboration of chemistry, physics, biology, material science ,computer with engineering – science and engineering focused on creating materials, devices and systems at atomic and molecular level.

Is an anticipated manufacturing technology that allows through, inexpensive control of structure of matter by working with atoms

Nobel laureate Richard Feynman In 1959- principles of physics do not speak against the possibility of manoeuvring things atom by atom- there is plenty of room at bottom

Drexler Nanotechnology is the principle of atom manipulation atom by atom, through control of the structure of matter at the molecular level.

Binning and Rohrer Expanded Drexler’s theory in practical way 1981 they were the first to ‘see’ atoms and hence made nanotechnology possible Able to pick up and move atoms to build structures

Origin of the word nano comes from the Greek word for ‘dwarf’ Scientifically nano means 10-9 So nano technology means building useful things at 10-9 level

Assemblers machine that will produce vast number of nano structures and also produce other machines to do this (OR) device having a nanorobot under computer control - can both build nano machine and reproduce itself in the same process ie they can build copies of them selves – ie to replicate

Able to build objects cheaply- by ensuring that each atom is properly placed- high quality products and reliability- left over molecules disassembled and reused –so clean process Able to form any one of several different kinds of chemical bonds.

Is this a fiction These type already exist in biology called as ribosome's. Can these assemblers misused? Nano machine viruses? Combine biotechnology, nanotechnology and genetic engineering – new life

Difference between a tool and a machine

Nanotechnology is largely concerned with solid phase because molecules or atoms do not move around so much –so easy to see In solid phase regular arrangement is easy- both amorphous and crystalline possible

Nanotechnology is concerned with single layers of atoms or molecules.

Top down and bottom up Two approaches to create very small machines and devises Top down approach- Bottom up approach-

Scale of things 1 nanometer (nm) is approx the width of 10 hydrogen atoms, 30 metal atoms or 1 sugar molecule. 1nm = 1/1000 width of typical bacterium 1nm = millionth the size of a pinhead Why can’t we write the entire 24 vols of the Encylopedia Brittanica on a pin head?

Magnify the pin head 25,000 times 1 inch approx. 2.45cm Magnify the pin head 25,000 times area of pin head is then equal to the area of all the pages of the Encylopedia Britannica. All you have to do is reduce the size of the writing by 25,000 times Each dot on a page of the Encyclopedia has a diameter 1/120 inch roughly or 0.204mm. De-magnify 25,000 times gives us a diameter 8.2nm or about 30 atoms across in a typical metal (which they use for pins). So there’s plenty of room to write Britannica on a pin head.

Library of congress has approx 9 million vols. British museum has 5 million or so National Library in France has 5 million also There are many duplications so lets guess at 24 million vols. of interest in the world. How much space would this take if we de-magnify by 25,000 times? It would take 1 million pin heads of course!! INSTEAD OF 24 VOLS. WE HAVE 24 MILLION VOLS. 1 million pinheads can be put together to form a flat square 1000x1000 pinheads about 3906 sq inches or 36 pages of 12x9inch paper. (36 pages is a small magazine- all the vols. in the world could be written on it)

In the section on “Information on a small scale” Feynman calculates the number of bits of information there are in all the vols. in the world (assuming they are all as big as a vol. of Encyclopedia Britt.) Bits of information in total. 6 or 7 bits per letter. Allow each bit 100 or 5x5x4 atoms. Using all the bulk volume of the material, not just the surface, then all information in all the vols. in the world can be stored in a cube of material 1/200 inch wide. This is the size of a small grain of dust. There’s PLENTY of room at the bottom!!

Some Problems in biology and chemistry now answered Feynman asked what are the most pressing problems in biology today 1959? What are the base sequences in DNA? What happens when you have a mutation? How is the base order in the DNA connected to the order of the amino acids in the protein? What is the structure of the RNA; is it a single chain or double chain and how does it relate to DNA? How are the proteins synthesized? Where do the RNA go? Where do the proteins sit? The amino acids? In photosynthesis, where does the chlorophyll go? What is the system for converting light into energy in plants?

It is easy to answer some of these questions It is easy to answer some of these questions. You just look at the thing In 1959, the microscopes where a bit too crude- not any more. Can physicists do something about chemistry– namely explain synthesis? Is there a physical way to synthesize any chemical substance? Not in 1959, but now progress is being made in this area.

A few nanometer milestones reached 1959 Feynman’s talk- prospects for miniaturization investigated 1968 Alfred Cho and John Arthur of Bell labs invent molecular –beam epitaxy, a technique to deposit single atomic layers on a surface 1981 Gerd Binnig and Heinrich Rohrer create the STM which can image single atoms. Nobel prize. 1985 Robert Curl, Harold Kroto and Richard Smalley discover bucky balls which are about 1 nm in diameter

1986 K. Eric Drexler publishes “Engines of Creation” a futuristic book about nanotech 1989 Donald Eiger of IBM writes letters “IBM” using single atoms 1991 Sumio Iijima of NEC Japan discovers carbon nanotubes. 1993 Warren Robinett of Univ N Carolina and R. Stanley Williams of UCLA devise a virtual reality system connected to an STM that lets users see and touch atoms 1998 Delft Univ. of Technolgy in Netherlands creates a transistor from a carbon nanotube

1999 James Tour, now at Rice U. and Mark Reed of Yale demonstrate that single molecules can act as switches. (snap a wire then put molecule between STM like tips) 2000 The Clinton administration announces NNI, the National Nantotechnology Initiative- large funding now available for projects in nanotech. 2000 Eigler and other devise a quantum mirage- placing a magnetic atom at the focus of an elliptical ring of atoms creates an mirage atom at the other focus- transmitting info without wires?

The Nano factory Integrate large numbers of nanoscale chemical fabrication units Combine nanoscale pieces into large-scale products General-purpose manufacturing in a tabletop format Extremely advanced products with compact functionality Produce its own weight in hours; produce copies of itself

Molecular nanotechnology