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Computational molecular nanotechnology Ralph C. Merkle Xerox PARC www.merkle.com Remember this URL: http://nano.xerox.com/nano Sixth Foresight Conference on Molecular Nanotechnology November 12-15, 1998 Santa Clara, California www.foresight.org/Conferences

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computational molecular nanotechnology

Computational molecular nanotechnology

Ralph C. Merkle

Xerox PARC

www.merkle.com

slide3
Sixth Foresight Conference on Molecular NanotechnologyNovember 12-15, 1998Santa Clara, Californiawww.foresight.org/Conferences
slide4
The best technical introduction to molecular nanotechnology:Nanosystems by K. Eric Drexler,Wiley 1992
slide5

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

today s manufacturing methods move atoms in great thundering statistical herds
Today’s manufacturing methods move atoms in great thundering statistical herds
  • Casting
  • Grinding
  • Welding
  • Sintering
  • Lithography
molecular nanotechnology a k a molecular manufacturing
Molecular 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

slide8

Possible arrangements of atoms

What we can make today

(not to scale)

.

slide10

Molecular

Manufacturing

We don’t have

molecular manufacturing today.

We must develop fundamentally new capabilities.

.

What we can make today

(not to scale)

slide11

Molecular

Manufacturing

What we can

investigate experimentally

.

What we can make today

(not to scale)

slide12

Molecular

Manufacturing

What we can

investigate

theoretically

.

What we can make today

(not to scale)

slide13
“... the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new. This coolness arises ... from the incredulity of men, who do not readily believe in new things until they have had a long experience of them.”

The Prince, by Niccolo Machiavelli

slide14

Products

Products

Core molecular

manufacturing

capabilities

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Today

Products

Products

Products

Products

Products

Overview of the development of molecular nanotechnology

Products

Products

Products

Products

Products

Products

Products

Products

working backwards from the goal as well as forwards from the start
Working backwards from the goal as well as forwards from the start
  • Backward chaining (Eric Drexler)
  • Horizon mission methodology (John Anderson)
  • Retrosynthetic analysis (Elias J. Corey)
  • Shortest path and other search algorithms in computer science
  • “Meet in the middle” attacks in cryptography
two more fundamental ideas
Two more fundamental ideas
  • Self replication (for low cost)
  • Programmable positional control (to make molecular parts go where we want them to go)
slide17

Complexity of self replicating systems

(bits)

  • Von Neumann's universal constructor about 500,000
  • 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

a c program that prints out an exact copy of itself

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

english translation

English translation:

Print the following statement twice, the second time in quotes:

“Print the following statement twice, the second time in quotes:”

slide20

Von Neumann architecture for a self replicating system

Universal

Computer

Universal

Constructor

slide21

Drexler’s architecture for an assembler

Molecular

computer

Molecular

constructor

Positional device

Tip chemistry

slide22

Advanced Automation for Space Missions

Proceedings of the 1980 NASA/ASEE Summer Study

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.

http://nano.xerox.com/nanotech/selfRepNASA.html

diamond physical properties
Diamond Physical Properties

PropertyDiamond’s valueComments

Chemical reactivity Extremely low

Hardness (kg/mm2) 9000 CBN: 4500 SiC: 4000

Thermal conductivity (W/cm-K) 20 Ag: 4.3 Cu: 4.0

Tensile 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: 1.4

Resistivity (W-cm) 1016 (natural)

Density (gm/cm3) 3.51

Thermal Expansion Coeff (K-1) 0.8 x 10-6 SiO2: 0.5 x 10-6

Refractive index 2.41 @ 590 nm Glass: 1.4 - 1.8

Coeff. of Friction 0.05 (dry) Teflon: 0.05

Source: Crystallume

classical uncertainty
Classical uncertainty

σ: RMS positional error

k: restoring force

kb: Boltzmann’s constant

T: temperature

a numerical example of classical uncertainty
A numerical example of classical uncertainty

σ: 0.02 nm (0.2 Å)

k: 10 N/m

kb: 1.38 x 10-23 J/K

T: 300 K

transverse stiffness of a solid cylinder of radius r and length l
Transverse stiffness of a solid cylinder of radius r and length L

E: Young’s modulus

k: transverse stiffness

r: radius

L: length

transverse stiffness of a solid cylinder of radius r and length l34
Transverse stiffness of a solid cylinder of radius r and length L

E: 1012 N/m2

k: 10 N/m

r: 8 nm

L: 100 nm

synthesis of diamond today diamond cvd
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.

slide36

A hydrogen abstraction tool

http://nano.xerox.com/nanotech/Habs/Habs.html

a synthetic strategy for the synthesis of diamondoid structures
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
a modest set of molecular tools should be sufficient to synthesize most stiff hydrocarbons
A modest set of molecular tools should be sufficient to synthesize most stiff hydrocarbons.

http://nano.xerox.com/nanotech/

hydroCarbonMetabolism.html

the hydrocarbon assembler
The hydrocarbon assembler
  • Simplifies molecular tools
  • Simplifies reaction pathways
  • Simplifies analysis
  • Simplifies feedstock
  • But a much narrower range of structures (stiff hydrocarbons)
feedstock
Feedstock
  • Acetone (solvent)
  • Butadiyne (C4H2, diacetylene: source of carbon and hydrogen)
  • Neon (inert, provides internal pressure)
  • “Vitamin” (transition metal catalyst such as platinum; silicon; tin)

http://nano.xerox.com/nanotech/hydroCarbonMetabolism.html

parts closure for molecular tools
Parts closurefor molecular tools
  • A set of synthetic pathways that permits construction of all molecular tools from the feedstock.
  • Can’t “go downhill,” must be able to make a new complete set of molecular tools while preserving the original set.
  • http://nano.xerox.com/nanotech/hydroCarbonMetabolism.html (about two dozen reactions)
we could design and model a simple hydrocarbon assembler today
We could design and modela simple hydrocarbon assembler today
  • Speed the development of the technology
  • Allow rapid and low cost exploration of design alternatives
  • Provide a clearer target for experimental work
  • Give us a clearer picture of what this technology will be able to do
critical assumptions in the design of a diamondoid assembler
Critical assumptions in the design of a diamondoid assembler
  • Must synthesize diamond
  • Highly reactive tools
  • Inert environment
  • Positional control
  • Low error rate (10-12)
  • Rapid unit operations (~10-6 seconds)
  • Simple feedstock