21-01-2013, 12:44 PM
Nanotechnology
1Nanotechnology.pdf (Size: 327.56 KB / Downloads: 64)
ABSTRACT
A nanometer is one billionth of a meter. If you blew up a baseball to the size of the
earth, the atoms would become visible, about the size of grapes. Some 3- 4 atoms fit
lined up inside a nanometer. Nanotechnology is about building things atom by atom,
molecule by molecule. The trick is to be able to manipulate atoms individually, and
place them where you wish on a structure.
Nanotechnology uses well known physical properties of atoms and molecules to make
novel devices with extraordinary properties. The anticipated pay off for mastering this
technology is beyond any human accomplishment thus far.
Nature uses molecular machines to create life.Scientists from several fields including
chemistry, biology, physics, and electronics are driving towards the precise
manipulation of matter on the atomic scale. How do we get to nanotechnology? Several
approaches seem feasible. Ultimately a combination may be the key.
INTRODUCTION
A nanometer is one billionth of a meter. That's a thousand, million times smaller than a meter. If
you blew up a baseball to the size of the earth, the atoms would become visible, about the size of
grapes. Some 3- 4 atoms fit lined up inside a nanometer. Nanotechnology is about building things
atom-by-atom, molecule-by-molecule. The trick is to be able to manipulate atoms individually, and
place them where you wish on a structure.
LEARNING FROM NATURE
Technology-as-we-know-it is a product of industry, of manufacturing and chemical
engineering. Industry-as-we-know-it takes things from nature—ore from mountains, trees
from forests—and coerces them into forms that someone considers useful. Trees become
lumber, then houses. Mountains become rubble, then molten iron, then steel, then cars. Sand
becomes a purified gas, then silicon, and then chips. And so it goes. Each process is crude,
based on cutting, stirring, baking, spraying, etching, grinding, and the like.
Trees, though, are not crude: To make wood and leaves, they neither cut, grind, stir, bake,
spray, etch, nor grind. Instead, they gather solar energy using molecular electronic devices,
the photosynthetic reaction centers of chloroplasts. They use that energy to drive molecular
machines—active devices with moving parts of precise, molecular structure—which process
carbon dioxide and water into oxygen and molecular building blocks.
NANOTECHNOLOGY-AS AN INTERDISCIPLINARY SUBJECT
Another feature of nanotechnology is that it is the one area of research and development that
is truly multidisciplinary. Research at the nanoscale is unified by the need to share
knowledge on tools and techniques, as well as information on the physics affecting atomic
and molecular interactions in this new realm. Materials scientists, mechanical and electronic
engineers and medical researchers are now forming teams with biologists, physicists and
chemists
BOTTOM-UP TECHNOLOGY
The two fundamentally different approaches to nanotechnology are graphically termed 'top
down' and 'bottom up'. 'Top-down' refers to making nanoscale structures by machining and
etching techniques, whereas 'bottom-up', or molecular nanotechnology, applies to building
organic and inorganic structures atom-by-atom, or molecule-by-molecule. Top-down or
bottom-up is a measure of the level of advancement of nanotechnology
NANOMACHINES
Manufactured products are made from atoms. The properties of those products depend on
how those atoms are arranged. If we rearrange the atoms in coal we can make diamond. If we
rearrange the atoms in sand (and add a few other trace elements) we can make computer
chips. If we rearrange the atoms in dirt, water and air we can make potatoes.
In future we'll be able to snap together the fundamental building blocks of nature easily,
inexpensively and in most of the ways permitted by the laws of physics. This will be
essential if we are to continue the revolution in computer hardware beyond about the next
decade, and will also let us fabricate an entire new generation of products that are cleaner,
stronger, lighter, and more precise.
Self Assembly
The ability of chemists to synthesize what they want by stirring things together is truly
remarkable. Imagine building a radio by putting all the parts in a bag, shaking, and pulling
out the radio -- fully assembled and ready to work! Self assembly -- the art and science of
arranging conditions so that the parts themselves spontaneously assemble into the desired
structure -- is a well established and powerful method of synthesizing complex molecular
structures.
A basic principle in self assembly is selective stickiness: if two molecular parts have
complementary shapes and charge patterns -- one part has a hollow where the other part has a
bump, and one part has a positive charge where the other part has a negative charge -- then
they will tend to stick together in one particular way. By shaking these parts around --
something which thermal noise does for us quite naturally if the parts are floating in solution
-- the parts will eventually, purely by chance, be brought together in just the right way and
combine into a bigger part. This bigger part can combine in the same way with other parts,
letting us gradually build a complex whole from molecular pieces by stirring them together
and shaking.
1Nanotechnology.pdf (Size: 327.56 KB / Downloads: 64)
ABSTRACT
A nanometer is one billionth of a meter. If you blew up a baseball to the size of the
earth, the atoms would become visible, about the size of grapes. Some 3- 4 atoms fit
lined up inside a nanometer. Nanotechnology is about building things atom by atom,
molecule by molecule. The trick is to be able to manipulate atoms individually, and
place them where you wish on a structure.
Nanotechnology uses well known physical properties of atoms and molecules to make
novel devices with extraordinary properties. The anticipated pay off for mastering this
technology is beyond any human accomplishment thus far.
Nature uses molecular machines to create life.Scientists from several fields including
chemistry, biology, physics, and electronics are driving towards the precise
manipulation of matter on the atomic scale. How do we get to nanotechnology? Several
approaches seem feasible. Ultimately a combination may be the key.
INTRODUCTION
A nanometer is one billionth of a meter. That's a thousand, million times smaller than a meter. If
you blew up a baseball to the size of the earth, the atoms would become visible, about the size of
grapes. Some 3- 4 atoms fit lined up inside a nanometer. Nanotechnology is about building things
atom-by-atom, molecule-by-molecule. The trick is to be able to manipulate atoms individually, and
place them where you wish on a structure.
LEARNING FROM NATURE
Technology-as-we-know-it is a product of industry, of manufacturing and chemical
engineering. Industry-as-we-know-it takes things from nature—ore from mountains, trees
from forests—and coerces them into forms that someone considers useful. Trees become
lumber, then houses. Mountains become rubble, then molten iron, then steel, then cars. Sand
becomes a purified gas, then silicon, and then chips. And so it goes. Each process is crude,
based on cutting, stirring, baking, spraying, etching, grinding, and the like.
Trees, though, are not crude: To make wood and leaves, they neither cut, grind, stir, bake,
spray, etch, nor grind. Instead, they gather solar energy using molecular electronic devices,
the photosynthetic reaction centers of chloroplasts. They use that energy to drive molecular
machines—active devices with moving parts of precise, molecular structure—which process
carbon dioxide and water into oxygen and molecular building blocks.
NANOTECHNOLOGY-AS AN INTERDISCIPLINARY SUBJECT
Another feature of nanotechnology is that it is the one area of research and development that
is truly multidisciplinary. Research at the nanoscale is unified by the need to share
knowledge on tools and techniques, as well as information on the physics affecting atomic
and molecular interactions in this new realm. Materials scientists, mechanical and electronic
engineers and medical researchers are now forming teams with biologists, physicists and
chemists
BOTTOM-UP TECHNOLOGY
The two fundamentally different approaches to nanotechnology are graphically termed 'top
down' and 'bottom up'. 'Top-down' refers to making nanoscale structures by machining and
etching techniques, whereas 'bottom-up', or molecular nanotechnology, applies to building
organic and inorganic structures atom-by-atom, or molecule-by-molecule. Top-down or
bottom-up is a measure of the level of advancement of nanotechnology
NANOMACHINES
Manufactured products are made from atoms. The properties of those products depend on
how those atoms are arranged. If we rearrange the atoms in coal we can make diamond. If we
rearrange the atoms in sand (and add a few other trace elements) we can make computer
chips. If we rearrange the atoms in dirt, water and air we can make potatoes.
In future we'll be able to snap together the fundamental building blocks of nature easily,
inexpensively and in most of the ways permitted by the laws of physics. This will be
essential if we are to continue the revolution in computer hardware beyond about the next
decade, and will also let us fabricate an entire new generation of products that are cleaner,
stronger, lighter, and more precise.
Self Assembly
The ability of chemists to synthesize what they want by stirring things together is truly
remarkable. Imagine building a radio by putting all the parts in a bag, shaking, and pulling
out the radio -- fully assembled and ready to work! Self assembly -- the art and science of
arranging conditions so that the parts themselves spontaneously assemble into the desired
structure -- is a well established and powerful method of synthesizing complex molecular
structures.
A basic principle in self assembly is selective stickiness: if two molecular parts have
complementary shapes and charge patterns -- one part has a hollow where the other part has a
bump, and one part has a positive charge where the other part has a negative charge -- then
they will tend to stick together in one particular way. By shaking these parts around --
something which thermal noise does for us quite naturally if the parts are floating in solution
-- the parts will eventually, purely by chance, be brought together in just the right way and
combine into a bigger part. This bigger part can combine in the same way with other parts,
letting us gradually build a complex whole from molecular pieces by stirring them together
and shaking.