Transcript There’s Nothing Small about Nanotechnology http://nano.xerox.com/nano Ralph C. Merkle Xerox PARC www.merkle.com See http://nano.xerox.com/nanotech/talks for an index of talks.

There’s Nothing Small about
Nanotechnology
http://nano.xerox.com/nano
Ralph C. Merkle
Xerox PARC
www.merkle.com
1
See
http://nano.xerox.com/nanotech/talks
for an index of talks
2
The best technical introduction to
molecular nanotechnology:
Nanosystems by K. Eric Drexler,
Wiley 1992
3
Sixth Foresight Conference on
Molecular Nanotechnology
November 12-15
Santa Clara, CA
www.foresight.org/Conferences
4
Seventh Elba-Foresight
Conference on
Nanotechnology
April, 1999
Rome, Italy
www.foresight.org/Conferences
5
Manufactured products are made
from atoms.
The properties of those products
depend on how those atoms are
arranged.
6
It matters
how atoms are arranged
• Coal
• Sand
• Dirt, water
and air
• Diamonds
• Computer chips
• Grass
7
Today’s manufacturing
methods move atoms in great
thundering statistical herds
•
•
•
•
•
Casting
Grinding
Welding
Sintering
Lithography
8
The principles of physics, as far as I can see,
do not speak against the possibility of
maneuvering things atom by atom. It is not an
attempt to violate any laws; it is something, in
principle, that can be done; but in practice, it
has not been done because we are too
big.
Richard Feynman, 1959
http://nano.xerox.com/nanotech/feynman.html
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Most interesting structures that are at
least substantial local minima on a
potential energy surface can probably be
made one way or another.
Richard Smalley
Nobel Laureate in Chemistry, 1996
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Nanotechnology
(a.k.a. molecular manufacturing)
• Fabricate most structures that are
specified with molecular detail and
which are consistent with physical law
• Get essentially every atom in the right
place
• Inexpensive manufacturing costs
(~10-50 cents/kilogram)
http://nano.xerox.com/nano
11
Terminological caution
The word “nanotechnology” has become very
popular. It has been used to refer to almost
any research area where some dimension is
less than a micron (1,000 nanometers) in
size.
Example: sub-micron lithography
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Born-Oppenheimer
approximation
• A carbon nucleus is more than 20,000
times as massive as an electron, so it
will move much more slowly
• Assume the nuclei are fixed and
unmoving, and then compute the
electronic wave function
• This is fundamental to molecular
mechanics
13
Quantum positional
uncertainty in the ground state

 
2 km
2
σ 2:
k:
m:
ħ:
positional variance
restoring force
mass of particle
Planck’s constant divided by 2π
14
Quantum uncertainty in
position
•
•
•
•
C-C spring constant:
Typical C-C bond length:
σ for C in single C-C bond:
σ for electron (same k):
k~440 N/m
0.154 nm
0.004 nm
0.051 nm
15
Molecular mechanics
• Nuclei are point masses
• Electrons are in the ground state
• The energy of the system is fully
determined by the nuclear positions
• Directly approximate the energy from
the nuclear positions, and we don’t even
have to compute the electronic structure
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Energy
Example: H2
Internuclear distance
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Molecular mechanics
•
•
•
•
•
•
•
Internuclear distance for bonds
Angle (as in H2O)
Torsion (rotation about a bond, C2H6
Internuclear distance for van der Waals
Spring constants for all of the above
More terms used in many models
Quite accurate in domain of parameterization
18
Possible arrangements of
atoms
What we can make today
(not to scale)
.
19
The goal of molecular
nanotechnology:
a healthy bite.
.
20
Molecular
Manufacturing
We don’t have
molecular manufacturing
today.
.
We must develop
fundamentally new
capabilities.
What we can make today
(not to scale)
21
Today
Overview of the
development of
molecular
nanotechnology
Produc
Products
Core molecular
Products
Products
manufacturing
Products
capabilities
Products Products
Products
Products
Products Products
Products Products
Products
Products
Products
Products
Products
Products
Products
Products
Produc
Products
Products Products
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Products
Two more fundamental ideas
• Self replication (for low cost)
• Programmable positional control (to
make molecular parts go where we
want them to go)
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Von Neumann architecture
for a self replicating system
Universal
Computer
Universal
Constructor
http://nano.xerox.com/nanotech/vonNeumann.html
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Drexler’s architecture for an
assembler
Molecular
computer
Molecular
constructor
Positional device
Tip chemistry
25
Illustration of an assembler
http://www.foresight.org/UTF/Unbound_LBW/chapt_6.html
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The theoretical concept of machine
duplication is well developed. There are
several alternative strategies by which
machine self-replication can be carried out
in a practical engineering setting.
Advanced Automation for Space Missions
Proceedings of the 1980 NASA/ASEE Summer
Study
http://nano.xerox.com/nanotech/selfRepNASA.html
27
A C program that prints out
an exact copy of itself
main(){char q=34, n=10,*a="main()
{char q=34,n=10,*a=%c%s%c;
printf(a,q,a,q,n);}%c";printf(a,q,a,q,n);}
For more information, see the Recursion Theorem:
http://nano.xerox.com/nanotech/selfRep.html
28
English translation:
Print the following statement twice,
the second time in quotes:
“Print the following statement twice,
the second time in quotes:”
29
Complexity of self replicating systems
(bits)
C program
808
Von Neumann's universal constructor500,000
Internet worm (Robert Morris, Jr., 1988)
500,000
Mycoplasma capricolum
1,600,000
E. Coli
9,278,442
Drexler's assembler
100,000,000
Human
6,400,000,000
NASA Lunar
Manufacturing Facility
over 100,000,000,000
http://nano.xerox.com/nanotech/selfRep.html
30
How cheap?
• Potatoes, lumber, wheat and other
agricultural products are examples of
products made using a self replicating
manufacturing base. Costs of roughly a
dollar per pound are common.
• Molecular manufacturing will make almost
any product for a dollar per pound or less,
independent of complexity. (Design costs,
licensing costs, etc. not included)
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How strong?
• Diamond has a strength-to-weight ratio
over 50 times that of steel or aluminium
alloy
• Structural (load bearing) mass can be
reduced by about this factor
• When combined with reduced cost, this
will have a major impact on aerospace
applications
32
How long?
• The scientifically correct answer is
I don’t know
• Trends in computer hardware suggest
early in the next century — perhaps in
the 2010 to 2020 time frame
• Of course, how long it takes depends on
what we do
33
Developmental pathways
• Scanning probe microscopy
• Self assembly
• Hybrid approaches
34
Moving molecules with an SPM
(Gimzewski et al.)
http://www.zurich.ibm.com/News/Molecule/
35
Self assembled DNA octahedron
(Seeman)
http://seemanlab4.chem.nyu.edu/nano-oct.html
36
DNA on an SPM tip
(Lee et al.)
http://stm2.nrl.navy.mil/1994scie/1994scie.html
37
Buckytubes
(Tough, well defined)
38
Bucky tube glued to SPM tip
(Dai et al.)
http://cnst.rice.edu/TIPS_rev.htm
39
Building the tools to build the tools
• Direct manufacture of a diamondoid
assembler using existing techniques
appears difficult (stronger statements
have been made).
• We should be able to build intermediate
systems able to build better systems
able to build diamondoid assemblers.
40
Diamond Physical Properties
Property
Diamond’s value Comments
Chemical reactivity
Hardness (kg/mm2)
Thermal conductivity (W/cm-K)
Tensile strength (pascals)
Compressive strength (pascals)
Band gap (ev)
Resistivity (W-cm)
Density (gm/cm3)
Thermal Expansion Coeff (K-1)
Refractive index
Coeff. of Friction
Extremely low
9000
20
3.5 x 109 (natural)
1011 (natural)
5.5
1016 (natural)
3.51
0.8 x 10-6
2.41 @ 590 nm
0.05 (dry)
CBN: 4500 SiC: 4000
Ag: 4.3 Cu: 4.0
1011 (theoretical)
5 x 1011 (theoretical)
Si: 1.1 GaAs: 1.4
SiO2: 0.5 x 10-6
Glass: 1.4 - 1.8
Teflon: 0.05
Source: Crystallume
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A hydrocarbon bearing
http://nano.xerox.com/nanotech/bearingProof.html
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A planetary gear
http://nano.xerox.com/nanotech/gearAndCasing.html
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A proposal for a molecular
positional device
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Classical uncertainty
kbT
 
k
2
σ:
k:
kb:
T:
mean positional error
restoring force
Boltzmann’s constant
temperature
45
A numerical example of
classical uncertainty
kbT
 
k
2
σ:
k:
kb:
T:
0.02 nm (0.2 Å)
10 N/m
1.38 x 10-23 J/K
300 K
46
Molecular tools
• Today, we make things at the molecular scale
by stirring together molecular parts and
cleverly arranging things so they
spontaneously go somewhere useful.
• In the future, we’ll have molecular “hands”
that will let us put molecular parts exactly
where we want them, vastly increasing the
range of molecular structures that we can
build.
47
Synthesis of diamond today:
diamond CVD
• Carbon: methane (ethane, acetylene...)
• Hydrogen: H2
• Add energy, producing CH3, H, etc.
• Growth of a diamond film.
The right chemistry, but little control over the site of
reactions or exactly what is synthesized.
48
A hydrogen abstraction tool
http://nano.xerox.com/nanotech/Habs/Habs.html
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Some other molecular tools
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A synthetic strategy for the synthesis
of diamondoid structures
• Positional control (6 degrees of
freedom)
• Highly reactive compounds (radicals,
carbenes, etc)
• Inert environment (vacuum, noble gas)
to eliminate side reactions
51
The impact of molecular
manufacturing
depends on what’s being
manufactured
•
•
•
•
•
Computers
Space Exploration
Medicine
Military
Energy, Transportation, etc.
52
How powerful?
• In the future we’ll pack more computing
power into a sugar cube than the sum
total of all the computer power that
exists in the world today
• We’ll be able to store more than 1021
bits in the same volume
• Or more than a billion Pentiums
operating in parallel
53
Space
• Launch vehicle structural mass will be
reduced by about a factor of 50
• Cost per pound for that structural mass
will be under a dollar
• Which will reduce the cost to low earth
orbit by a factor of better than 1,000
http://science.nas.nasa.gov/Groups/Nanotechnol
ogy/publications/1997/applications/
54
It costs less to launch less
• Light weight computers and sensors will
reduce total payload mass for the same
functionality
• Recycling of waste will reduce payload
mass, particularly for long flights and
permanent facilities (space stations,
colonies)
55
Disease and illness are
caused largely by damage at
the molecular and cellular
level
Today’s surgical tools are
huge and imprecise in
comparison
56
http://nano.xerox.com/nanotech/
In the future, we will have fleets
of surgical tools that are
molecular both in size and
precision.
We will also have computers
that are much smaller than a
single cell with which to guide
these tools.
57
A revolution in medicine
• Today, loss of cell function results in cellular
deterioration:
function must be preserved
• With future cell repair systems, passive
structures can be repaired. Cell function can
be restored provided cell structure can be
inferred:
structure must be preserved
58
Cryonics
37º C
37º C
Temperature
Freeze
Revive
-196º C (77 Kelvins)
Time
(~ 50 to 150 years)
59
Clinical trials
to evaluate cryonics
•
•
•
•
Select N subjects
Freeze them
Wait 100 years
See if the medical technology of 2100 can
indeed revive them
But what do we tell those who don’t expect to
live long enough to see the results?
60
Today’s choice:
would you rather join
The control group
(no action required)?
Or the experimental group
(contact Alcor: www.alcor.org)?
61
Military applications of molecular
manufacturing have even greater
potential than nuclear weapons to
radically change the balance of
power.
Admiral David E. Jeremiah, USN (Ret)
Former Vice Chairman, Joint Chiefs of
Staff
http://nano.xerox.com/nanotech/nano4/jeremiahPaper.htm
November 9, 1995
62
Environmental impact
depends on
• Population
• Living standards
• Technology
63
Molecular nanotechnology
and the environment
•
•
•
•
Low cost greenhouse agriculture
Low cost solar power
Pollution free manufacturing
The ultimate in recycling
64
Nanotechnology and energy
• The sunshine reaching the earth has
almost 40,000 times more power than
total world usage.
• Molecular manufacturing will produce
efficient, rugged solar cells and
batteries at low cost.
• Power costs will drop dramatically
65
Nanotechnology and the
environment
• Manufacturing plants pollute because
they use crude and imprecise methods.
• Molecular manufacturing is precise — it
will produce only what it has been
designed to produce.
• An abundant source of carbon is the
excess CO2 in the air
66
The best way
to predict the future
is to invent it.
Alan Kay
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