1 there’s nothing small about nanotechnology ralph c. merkle xerox parc
TRANSCRIPT
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There’s Nothing Small about
Nanotechnologyhttp://nano.xerox.com/nano
Ralph C. Merkle
Xerox PARC
www.merkle.com
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See
http://nano.xerox.com/nanotech/talks
for an index of talks
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The best technical introduction to molecular nanotechnology:
Nanosystems by K. Eric Drexler,Wiley 1992
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Sixth Foresight Conference on Molecular Nanotechnology
November 12-15Santa Clara, CA
www.foresight.org/Conferences
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Seventh Elba-Foresight Conference on
Nanotechnology
April, 1999Rome, Italy
www.foresight.org/Conferences
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Manufactured products are made from atoms.
The properties of those products depend on how those atoms are arranged.
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• Coal
• Sand
• Dirt, water and air
• Diamonds
• Computer chips
• Grass
It matters
how atoms are arranged
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Today’s manufacturing methods move atoms in great
thundering statistical herds
• Casting
• Grinding
• Welding
• Sintering
• Lithography
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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 anattempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are toobig.
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
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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
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Quantum positional uncertainty in the ground state
σ2: positional variance
k: restoring force
m: mass of particle
ħ: Planck’s constant divided by 2π
km22
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Quantum uncertainty in position
• C-C spring constant: k~440 N/m
• Typical C-C bond length: 0.154 nm• σ for C in single C-C bond: 0.004 nm• σ for electron (same k): 0.051 nm
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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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Example: H2
Internuclear distance
Ene
rgy
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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
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Possible arrangements of atoms
.
What we can make today(not to scale)
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The goal of molecular nanotechnology:
a healthy bite.
.
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What we can make today(not to scale)
.
We don’t havemolecular manufacturing today.
We must develop fundamentally new capabilities.
MolecularManufacturing
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Core molecularmanufacturingcapabilities
Today ProductsProducts
Products
Products
Products
Products
Products
Products
Products
ProductsProducts
Products
Products
Products
Products
Products
Products
Products
Products
Products
Products
ProductsProducts
Products
Products
Products
Overview of the development of molecular nanotechnology
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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
UniversalComputer
UniversalConstructor
http://nano.xerox.com/nanotech/vonNeumann.html
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Drexler’s architecture for an assembler
Molecularcomputer
Molecularconstructor
Positional device Tip chemistry
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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 MissionsProceedings of the 1980 NASA/ASEE Summer Study
http://nano.xerox.com/nanotech/selfRepNASA.html
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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
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English translation:
Print the following statement twice, the second time in quotes:
“Print the following statement twice, the second time in quotes:”
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C program 808Von Neumann's universal constructor 500,000Internet worm (Robert Morris, Jr., 1988) 500,000Mycoplasma capricolum 1,600,000E. Coli 9,278,442Drexler's assembler 100,000,000Human 6,400,000,000NASA Lunar
Manufacturing Facility over 100,000,000,000http://nano.xerox.com/nanotech/selfRep.html
Complexity of self replicating systems
(bits)
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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
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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
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Developmental pathways
• Scanning probe microscopy
• Self assembly
• Hybrid approaches
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Moving molecules with an SPM(Gimzewski et al.)
http://www.zurich.ibm.com/News/Molecule/
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Self assembled DNA octahedron(Seeman)
http://seemanlab4.chem.nyu.edu/nano-oct.html
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DNA on an SPM tip(Lee et al.)
http://stm2.nrl.navy.mil/1994scie/1994scie.html
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Buckytubes(Tough, well defined)
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Bucky tube glued to SPM tip(Dai et al.)
http://cnst.rice.edu/TIPS_rev.htm
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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.
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Diamond Physical Properties
Property Diamond’s value Comments
Chemical reactivity Extremely lowHardness (kg/mm2) 9000 CBN: 4500 SiC: 4000Thermal conductivity (W/cm-K) 20 Ag: 4.3 Cu: 4.0Tensile strength (pascals) 3.5 x 109 (natural) 1011 (theoretical)Compressive strength (pascals) 1011 (natural) 5 x 1011 (theoretical)Band gap (ev) 5.5 Si: 1.1 GaAs: 1.4Resistivity (W-cm) 1016 (natural)Density (gm/cm3) 3.51Thermal Expansion Coeff (K-1) 0.8 x 10-6 SiO2: 0.5 x 10-6Refractive index 2.41 @ 590 nm Glass: 1.4 - 1.8Coeff. of Friction 0.05 (dry) 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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Classical uncertainty
kTkb2
σ: mean positional error k: restoring forcekb: Boltzmann’s constantT: temperature
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A numerical example of classical uncertainty
kTkb2
σ: 0.02 nm (0.2 Å) k: 10 N/mkb: 1.38 x 10-23 J/KT: 300 K
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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.
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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.
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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
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The impact of molecular manufacturing
depends on what’s being manufactured
• Computers• Space Exploration• Medicine• Military• Energy, Transportation,
etc.
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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
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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/Nanotechnology/publications/1997/applications/
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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)
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Disease and illness are caused largely by damage at the molecular and cellular level
Today’s surgical tools are huge and imprecise in comparison
http://nano.xerox.com/nanotech/ nanotechAndMedicine.html
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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.
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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
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Cryonics37º C 37º C
-196º C (77 Kelvins)
Freeze Revive
Time
Tem
pera
ture
(~ 50 to 150 years)
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Clinical trialsto 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?
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Today’s choice:would you rather join
The control group (no action required)?
Or the experimental group
(contact Alcor: www.alcor.org)?
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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
StaffNovember 9, 1995
http://nano.xerox.com/nanotech/nano4/jeremiahPaper.html
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Environmental impact depends on
• Population
• Living standards
• Technology
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Molecular nanotechnology and the environment
• Low cost greenhouse agriculture
• Low cost solar power
• Pollution free manufacturing
• The ultimate in recycling
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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
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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
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The best wayto predict the
futureis to invent it.
Alan Kay