1. nanoscience - acclab.helsinki.fiknordlun/nanotiede/nanosc1nc.pdf · and nanotechnology” edward...

1. Nanoscience

Introduction to Nanoscience, Kai Nordlund 2005 JJ J � I II × 1

1.1. What is nanoscience

Nanoscience deals with the scientific study of objects with sizes in the 1 – 100 nm range in at

least one dimension.

Nanotechnology deals with using objects in the same size range to develop products with possible

practical application. It is usually based on nanoscience insights.

Nanobusiness means generating actual revenue out of nanotechology products.

These definitions are quite problematic in many ways, but it is not possible to give a more general

definition which everybody would agree on. The problem with these definitions is that most of

chemistry and materials physics and a sizeable fraction of materials engineering and biochemistry

would by the above definitions be nanoscience.

There does, however, exist a certain movement to do just that. E.g. the author of “Nanophysics

and Nanotechnology” Edward L. Wolf does in the book consider more or less all physics from the

atom level up, including traditional quantum physics, as “nanophysics”.


- If this is not just a fad, could lead to major redefining of borders of different scientific disciplines.

- In the lecturers opinion this is going too far, at least at this stage.

- Role of novelty and controllability

The crucial elements of nanoscience are that it is considered (and often is) genuinely new, and the

nanometer sized are manufactured in some sense in an intelligent and controllable manner. Hense

for something to be called nanoscience in a justifiable way it should be include novel scientific or

technological solutions on a nanometer scale, and these should be manufactured, manipulated or

analysed in a controlled manner.

Thus for instance any controlled use of nanoclusters, atom agglomerates with sizes in the 1 – 100

nm is nanoscience.

- Counterexample: defect clusters in solids

With these arguments we arrive at the lecturers own, currently best definition of nanoscience:


Nanoscience deals with the scientific study of objects with sizes in the 1 – 100 nm range in at

least one dimension. The objects are controlled on this size scale either in terms of manufacturing,

modification or analysis, and the research includes some aspect of novelty either in terms of material

studied, methods used or question asked.


1.2. Why is it interesting

Nanoscience is interesting in part of course because it by definition is new.

But a more profound and important reason is that it deals with objects which are only slightly

larger than an atom. This means that the properties of the objects can be influenced by direct

manifestations of quantum mechanics.

It is also possible that nanoscale objects do behave just like as expected from (semi)classical physics,

but the downgrading in size opens up possible new applications.

- Example: nanoxylophone. Works as classical resonator but because f ∝ 1/L can achieve GHz

audio frequencies!


The reason nanoscience is considered new is directly related to the small scale. It is only very

recently when it has become possible to manufacture and analyze objects on this scale, and some

of them are genuinely new.

- Example: nanocrystalline vs. polycrystalline metals: grain size and mechanical properties

Nanoscience is also interesting in that physics, chemistry and biology meet in a natural way in it.

Understanding of the interactions between atoms and/or the basics of quantum mechanics is crucial


in most branches of nanoscience, and hence regardless of the background of a nanoscientist he/she

needs to use these tools. The connection to biology might seem farfetched, but in fact computers

have advanced so much that so called molecular mechanics atomic interaction models developed

originally in molecular physics, and simulation algorithms developed originally in nuclear physics,

can now be directly used to study microbiological systems with millions of atoms.

In fact this in many cases leads to science where the traditional lines between physics, chemistry and

biology may be completely blurred, and many scientists might in fact soon prefer to call themselves

nanoscientists.

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1.3. Feynmans visions

The original vision that had a large role in leading to nanoscience was cast already in 1959 by nobel

laureate Richard Feynman in a talk he gave on December 29th 1959 at the annual meeting of the

American Physical Society. The title was “There’s Plenty of Room at the Bottom”

It is a very well written talk and interesting reading now that we have good capabilities for hindsight.

It is available on the course home page (and easily found on the web). I will here excerpt some

parts of it and comment of them:

1.3.1. Vision of nanoscience

Feynman:

I would like to describe a field, in which little has been done, but in which an enormous amount can be done in

principle. This field is not quite the same as the others in that it will not tell us much of fundamental physics (in

the sense of, “What are the strange particles?”) but it is more like solid-state physics in the sense that it might

tell us much of great interest about the strange phenomena that occur in complex situations. Furthermore, a point

that is most important is that it would have an enormous number of technical applications.


- Comment: this reminds us of the fact that nanoscience does not give us any fundamentalist

insights on the nature of the universe in a reductionist worldview, i.e. one which aims to reduce

the description of the universe to same mathematical equations. This is because nanoscience does

not go below object of atomic size, and physics knows well the fundamental objects are at least as

small as quarks and leptons, with sizes some 10 orders of magnitude below that of an atom.

Nanoscience might on the other hand give important insights into emergence, the concept that from

many enough simple interactions a complex whole may form (“more is different”) something which

computer simulations have proven explicitly. Thus nanoscience might give fundamental insights into

an emergent world view!

1.3.2. Atomic-level manufacturing

Feynman:

What I want to talk about is the problem of manipulating and controlling things on a small scale.

As soon as I mention this, people tell me about miniaturization, and how far it has progressed today. They tellme about electric motors that are the size of the nail on your small finger. And there is a device on the market,


they tell me, by which you can write the Lord’s Prayer on the head of a pin. But that’s nothing; that’s the mostprimitive, halting step in the direction I intend to discuss. It is a staggeringly small world that is below. In theyear 2000, when they look back at this age, they will wonder why it was not until the year 1960 that anybody beganseriously to move in this direction.

Why cannot we write the entire 24 volumes of the Encyclopedia Brittanica on the head of a pin?

Let’s see what would be involved. The head of a pin is a sixteenth of an inch across. If you magnify it by 25,000

diameters, the area of the head of the pin is then equal to the area of all the pages of the Encyclopaedia Brittanica.

Therefore, all it is necessary to do is to reduce in size all the writing in the Encyclopaedia by 25,000 times. Is that

possible? The resolving power of the eye is about 1/120 of an inch—that is roughly the diameter of one of the little

dots on the fine half-tone reproductions in the Encyclopaedia. This, when you demagnify it by 25,000 times, is still

80 angstroms in diameter—32 atoms across, in an ordinary metal. In other words, one of those dots still would

contain in its area 1,000 atoms. So, each dot can easily be adjusted in size as required by the photoengraving, and

there is no question that there is enough room on the head of a pin to put all of the Encyclopaedia Brittanica.

- Comment: it would now be possible to do exactly this, at least if the pin were of silicon and had

a flat head: electron beam lithography

Feynman: That’s the Encyclopaedia Brittanica on the head of a pin, but let’s consider all the books in the world.The Library of Congress has approximately 9 million volumes; the British Museum Library has 5 million volumes;


there are also 5 million volumes in the National Library in France. Undoubtedly there are duplications, so let ussay that there are some 24 million volumes of interest in the world.

...

What would our librarian at Caltech say, as she runs all over from one building to another, if I tell her that, ten

years from now, all of the information that she is struggling to keep track of— 120,000 volumes, stacked from the

floor to the ceiling, drawers full of cards, storage rooms full of the older books—can be kept on just one library

card!

- Comment: If we assume one book has on average 1 million characters (e.g. the bible has some

2 million) Feynmans 24 million books amount to 24 terabytes of storage. In a few years a single

RAID disk array could fit all that information, although not yet quite on a library card sized object.

So we have come close...

1.3.3. Connection between physics, chemistry and biology

Feynman: So it should be possible to see the individual atoms. What good would it be to see individual atomsdistinctly?

...

We have friends in other fields—in biology, for instance. We physicists often look at them and say, “You knowthe reason you fellows are making so little progress?” (Actually I don’t know any field where they are making more


rapid progress than they are in biology today.) “You should use more mathematics, like we do.” They could answerus—but they’re polite, so I’ll answer for them: “What you should do in order for us to make more rapid progressis to make the electron microscope 100 times better.”

What are the most central and fundamental problems of biology today? They are questions like: What is thesequence of bases in the DNA? What happens when you have a mutation? How is the base order in the DNAconnected to the order of amino acids in the protein? What is the structure of the RNA; is it single-chain ordouble-chain, and how is it related in its order of bases to the DNA? What is the organization of the microsomes?How are proteins synthesized? Where does the RNA go? How does it sit? Where do the proteins sit? Where dothe amino acids go in? In photosynthesis, where is the chlorophyll; how is it arranged; where are the carotenoidsinvolved in this thing? What is the system of the conversion of light into chemical energy?

It is very easy to answer many of these fundamental biological questions; you just look at the thing! You will seethe order of bases in the chain; you will see the structure of the microsome. Unfortunately, the present microscopesees at a scale which is just a bit too crude. Make the microscope one hundred times more powerful, and manyproblems of biology would be made very much easier.

....

But if the physicists wanted to, they could also dig under the chemists in the problem of chemical analysis. It wouldbe very easy to make an analysis of any complicated chemical substance; all one would have to do would be to lookat it and see where the atoms are.

...

A biological system can be exceedingly small. Many of the cells are very tiny, but they are very active; they


manufacture various substances; they walk around; they wiggle; and they do all kinds of marvelous things—all ona very small scale. Also, they store information. Consider the possibility that we too can make a thing very smallwhich does what we want—that we can manufacture an object that maneuvers at that level!

1.3.4. Nanomachines

Feynman:

...

What are the possibilities of small but movable machines? They may or may not be useful, but they surely wouldbe fun to make.

I don’t know how to do this on a small scale in a practical way, but I do know that computing machines are verylarge; they fill rooms. Why can’t we make them very small, make them of little wires, little elements—and by little,I mean little. For instance, the wires should be 10 or 100 atoms in diameter, and the circuits should be a fewthousand angstroms across.

- Comment: this is almost where conventional Si technology is now.

Feynman:

What are the possibilities of small but movable machines? They may or may not be useful, but they surely wouldbe fun to make.

A friend of mine (Albert R. Hibbs) suggests a very interesting possibility for relatively small machines. He says


that, although it is a very wild idea, it would be interesting in surgery if you could swallow the surgeon. You put themechanical surgeon inside the blood vessel and it goes into the heart and “looks” around. (Of course the informationhas to be fed out.) It finds out which valve is the faulty one and takes a little knife and slices it out. Other smallmachines might be permanently incorporated in the body to assist some inadequately-functioning organ.

- Comment: The original idea of nanomachines and their use in the human body.

Feynman:

But I am not afraid to consider the final question as to whether, ultimately—in the great future—we can arrangethe atoms the way we want; the very atoms, all the way down! What would happen if we could arrange the atomsone by one the way we want them.

- Comment: this is now possible on surfaces, thanks to the atomic force microscope.


1.4. Nanohype, nanoreality, and nanodreams

The rise of nanotechnology has also lead to hype about the possibilities and risks of this field.

One of the main proponents and hypers of the potential of nanotechnology is Eric Drexler, whose

original book “Engines of Creation: The Coming Era of Nanotechnology” has raised a lot of interest.

Although some of the ideas in the book are quite sound, some are rather utopistic and the level of

speculation is high. But when people without a scientific background read the book, they may take

all of it seriously, which can lead to both funny [see e.g. Dunkley, Futures 36 (2004) p. 1129] and

worrisome results.

Nanohype may also be a problem if it subjects nanotechnology development to too high expectations

of economic returns.

But the counterargument to claiming that all proponents of nanoscience are doing nanohype is that


nanotechnology has already lead to several products which are on the market, generate revenue,

and in some cases are dramatically better than pre-existing products.

- Sunscreen lotion with TiO2 particles

- Self-cleaning window panes

- Tennis racquets with nanoparticles and nanotubes

- Mobile phone batteries which can be charged in no time.

- Finland: company in Lohja with nanoparticle-active-fibre

- Finland: Nokia: phone coating which does not leave fingerprints .

- Finland: Orion nanoparticles as markers for molecules

The real nanomarkets are in a strong growth phase; for instance the world market for carbon

nanotubes has been estimated to grow at a pace of 200% a year.

There are even true nanotechnology dreams, visions which could radically change the course of

history, yet are maybe in the realms of the possible:


- Surgical use of nanorobots: cure cancer or even make people live forever

- An elevator to space

We will discuss these concepts critically towards the end of the course.


1.5. Historical uses of nanoscience

It is interesting to note that there has been use of what now would definitely be called nanoscience

much before the advent of the word.

- Vases used by old Greeks and Romans

- “Wootz” Damascus swords .

These historical uses fulfill my definition of nanoscience in every way except for the “controlled”


criterion. Indeed, the incredibly good damascene swords (by that days standards) could no longer

be manufactured after the iron producers changed their iron manufacturing method a bit. The

method for producing this wootz-steel with appealing surface patterns has been rediscoverd lately.


1. nanoscience - acclab.helsinki.fiknordlun/nanotiede/nanosc1nc.pdf · and nanotechnology” edward...

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