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Intermediate and long term objectives in nanotechnology. Ralph C. Merkle Xerox PARC www.merkle.com. Products. Products. Core molecular manufacturing capabilities. Products. Products. Products. Products. Products. Products. Products. Products. Products. Products. Products.

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Intermediate and long term objectives in nanotechnology

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Intermediate and long term objectives in nanotechnology l.jpg

Intermediate and long term objectives in nanotechnology

Ralph C. Merkle

Xerox PARC

www.merkle.com


Slide2 l.jpg

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


The abstract goal l.jpg

The abstract goal

  • 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


Two essential concepts l.jpg

Two essential concepts

  • Self replication (for low cost)

  • Programmable positional control (to make molecular parts go where we want them to go)


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Complexity of self replicating systems

(bits)

  • Von Neumann's universal constructorabout 500,000

  • Internet worm (Robert Morris, Jr., 1988)500,000

  • Mycoplasma capricolum1,600,000

  • E. Coli9,278,442

  • Drexler's assembler100,000,000

  • Human6,400,000,000

  • NASA Lunar

    • Manufacturing Facilityover 100,000,000,000

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


A proposal for a molecular positional device l.jpg

A proposal for a molecular positional device


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One embodiment of the goal:

Drexler’s assembler

Molecular

computer

Molecular

constructor

Positional device

Tip chemistry


Something a bit simpler the hydrocarbon assembler l.jpg

Something a bit simpler:the hydrocarbon assembler

  • We want to make diamond

  • The synthesis of diamond using CVD involves reactive species (carbenes, radicals)

  • This requires an inert environment and positional control to prevent side reactions

  • Focusing our attention on stiff hydrocarbons greatly simplifies design and modeling


Major subsystems in a simple assembler floating in solution l.jpg

Major subsystems in a simple assembler floating in solution

  • Positional device

  • Molecular tools

  • Barrier

  • Trans-barrier transport/binding sites

  • Neon intake

  • Pressure actuated ratchets

  • Pressure equilibration


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The value of a goal:we can work backwards from it(or: it’s hard to build something if you don’t know what it looks like)

  • 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


The focus today self replication and molecular tools l.jpg

The focus today: self replication and molecular tools

  • Molecular tools are made from feedstock molecule(s)

  • Molecular tools are made using an existing set of molecular tools

  • Starting with one set of molecular tools, we must end up with two full sets of molecular tools

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

hydroCarbonMetabolism.html


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A hydrogen abstraction tool

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


Some other molecular tools l.jpg

Some other molecular tools


Thermal noise a classical equation s 2 kt k s l.jpg

Thermal noise,a classical equation:s2 = kT/ks

  • s is the mean positional error (~0.02 nm)

  • k is Boltzmann’s constant (~1.38 x 10-23 J/K)

  • T is the temperature (~300 K)

  • ks is the stiffness (~ 10 N/m)

  • See page 91 of Nanosystems for a derivation and further discussion


Feedstock l.jpg

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


A simple binding site for butadiyne l.jpg

A simple binding site for butadiyne


These molecular tools should be able to synthesize a remarkably wide range of stiff hydrocarbons l.jpg

These molecular tools should be able to synthesize a remarkably wide range of stiff hydrocarbons.

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

hydroCarbonMetabolism.html


Overview l.jpg

Overview

  • Start with molecular tools and butadiyne

  • Finish with two sets of molecular tools

  • Assumes the availability of positional control in an inert environment (e.g., vacuum)


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Positioning and initially bonding to a molecule

  • Intermolecular forces must be used

  • Access is required for the molecular tool(s) which will first bond to the molecule

  • Once attached covalently to a molecular tool, further positional control can be achieved by moving the molecular tool

  • To position butadiyne for its first bonds, think of a hot dog in a hot dog bun


The first bonds to butadiyne l.jpg

The first bonds to butadiyne

  • Radicals could in principle attach at any of the six atoms in butadiyne

  • Carbenes could in principle insert into any of the five bonds in butadiyne


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Creating twohydrogen abstraction tools


Refreshing a hydrogen abstraction tool l.jpg

Refreshing ahydrogen abstraction tool


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Separating two hydrogen abstraction tools that are bonded together


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Radicals weaker than the hydrogen abstraction tool can be created by abstracting a hydrogen from the appropriate precursor


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We can dispose of excess hydrogen by making hydrogen rich structures


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Extending ahydrogen abstraction tool


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Transferring a dimer from a polyyne to a cumulene(the kind of reaction needed to refresh the carbene tool)


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Parts closure

  • We must be able to synthesize all tools from the available feedstock and a pre-existing set of molecular tools

  • Quantitative parts closure requires that such synthesis does not cause a depletion of the pre-existing set of tools

  • See http://nano.xerox.com/nanotech/ hydroCarbonMetabolism.html for further discussion


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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


The design and modeling of a simple assembler could be done with existing capabilities this would l.jpg

The design and modeling of a simple assembler could be done with existing capabilities.This would:

  • Clarify the goal

  • Speed the development of the technology

  • Allow rapid and low cost exploration of design alternatives

  • Clarify what this technology will be able to do


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