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Whither nanotechnology?. Ralph C. Merkle Distinguished Professor of Computing Georgia Tech College of Computing. Web pages. www.foresight.org. www.zyvex.com/nano. www.nano.gov. Health, wealth and atoms. Arranging atoms. Flexibility Precision Cost. Richard Feynman,1959.

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Whither nanotechnology

Whither nanotechnology?

Ralph C. Merkle

Distinguished Professor of Computing

Georgia Tech College of Computing


Whither nanotechnology

Web pages

www.foresight.org

www.zyvex.com/nano

www.nano.gov



Arranging atoms
Arranging atoms

  • Flexibility

  • Precision

  • Cost


Whither nanotechnology

Richard Feynman,1959

There’s plenty of room

at the bottom


1980 s 1990 s
1980’s, 1990’s

Experiment and theory

First STM

By Binnig and Rohrer


President clinton 2000
President Clinton, 2000

“Imagine the possibilities: materials with ten times the strength of steel and only a small fraction of the weight -- shrinking all the information housed at the Library of Congress into a device the size of a sugar cube -- detecting cancerous tumors when they are only a few cells in size.”

The National Nanotechnology Initiative


Whither nanotechnology

The goal

Arrangements of atoms

.

Today


Whither nanotechnology

The goal

The goal

.



Whither nanotechnology

Experimental

H. J. Lee and W. Ho, SCIENCE 286, p. 1719, NOVEMBER 1999



Whither nanotechnology

Molecular mechanics

  • Manufacturing is about moving atoms

  • Molecular mechanics studies the motions of atoms

  • Molecular mechanics is based on the Born-Oppenheimer approximation


Whither nanotechnology

Born-Oppenheimer

The carbon nucleus has a mass over 20,000 times that of the electron

  • Moves slower

  • Positional uncertainty smaller


Whither nanotechnology

Born-Oppenheimer

  • Treat nuclei as point masses

  • Assume ground state electrons

  • Then 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


Whither nanotechnology

Hydrogen molecule: H2

Energy

Internuclear distance





Whither nanotechnology

Thermal noise

σ: mean positional error

k: restoring force

kb: Boltzmann’s constant

T: temperature


Whither nanotechnology

Thermal noise

σ: 0.02 nm (0.2 Å)

k: 10 N/m

kb: 1.38 x 10-23 J/K

T: 300 K


What to make
What to make

Diamond physical properties

Property Diamond’s value Comments

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


Making diamond today
Making diamond today

Illustration courtesy of P1 Diamond Inc.




Some journal publications
Some journal publications

  • Theoretical Analysis of Diamond Mechanosynthesis. Part I. Stability of C2 Mediated Growth of Nanocrystalline Diamond C(110) Surface, J. Comp. Theor. Nanosci. 1(March 2004), Jingping Peng, Robert A. Freitas Jr., Ralph C. Merkle. In press.

  • Theoretical Analysis of Diamond Mechanosynthesis. Part II. C2 Mediated Growth of Diamond C(110) Surface via Si/Ge-Triadamantane Dimer Placement Tools, J. Comp. Theor. Nanosci. 1(March 2004). David J. Mann, Jingping Peng, Robert A. Freitas Jr., Ralph C. Merkle, In press.

  • Theoretical analysis of a carbon-carbon dimer placement tool for diamond mechanosynthesis, Ralph C. Merkle and Robert A. Freitas Jr., J. Nanosci. Nanotechnol. 3 June 2003. (Abstract)

  • A proposed "metabolism" for a hydrocarbon assembler, Nanotechnology8 (1997) pages 149-162.

  • Theoretical studies of reactions on diamond surfaces, by S.P. Walch and R.C. Merkle, Nanotechnology9 (1998) pages 285-296.

  • Theoretical studies of a hydrogen abstraction tool for nanotechnology, by Charles Musgrave, Jason Perry, Ralph C. Merkle and William A. Goddard III; Nanotechnology 2 (1991) pages 187-195.


Whither nanotechnology

Self replication

A redwood tree

(sequoia sempervirens)

112 meters tall

Redwood National Park

http://www.zyvex.com/nanotech/selfRep.html


Whither nanotechnology

Self replication

The Von Neumann architecture

Universal

Computer

Universal

Constructor

http://www.zyvex.com/nanotech/vonNeumann.html


Whither nanotechnology

Self replication

Drexler’s proposal for an assembler

http://www.foresight.org/UTF/Unbound_LBW/chapt_6.html




Self replication
Self replication

Kinematic Self-Replicating Machines (Landes Bioscience, 2004, in review).

Reviews the voluminous theoretical and experimental literature about physical self-replicating systems.

Freitas and Merkle


Whither nanotechnology

Replication

Manufacturing costsper kilogramwill be low

  • Today: potatoes, lumber, wheat, etc. are all about a dollar per kilogram.

  • Tomorrow: almost any product will be about a dollar per kilogram or less. (Design costs, licensing costs, etc. not included)


Impact
Impact

The impact

of a new manufacturing technology

depends on what you make


Impact1
Impact

Powerful Computers

  • We’ll have more computing power in the volume of a sugar cube than the sum total of all the computer power that exists in the world today

  • More than 1021 bits in the same volume

  • Almost a billion Pentiums in parallel


Impact2
Impact

Lighter, stronger,

smarter, less expensive

  • New, inexpensive materials with a strength-to-weight ratio over 50 times that of steel

  • Critical for aerospace: airplanes, rockets, satellites…

  • Useful in cars, trucks, ships, ...


Whither nanotechnology

Impact

  • 50x reduction of structural mass

  • Cost per kilogram under a dollar

  • Reducing cost to low earth orbit by 1,000 or more

  • http://science.nas.nasa.gov/Groups/

  • Nanotechnology/publications/1997/

  • applications/


Impact3
Impact

Size of a robotic arm

~100 nanometers

8-bit computer

Mitochondrion

~1-2 by 0.1-0.5 microns


Scale
Scale

Mitochondrion

Size of a robotic arm ~100 nanometers

8-bit computer

“Typical” cell: ~20 microns





Survey of the field
Survey of the field

Nanomedicine

  • Surveys medical applications of nanotechnology

  • Volume I (of three) published in 1999

  • Robert Freitas, Zyvex

http://www.foresight.org/Nanomedicine


Whither nanotechnology

Global Security

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

November 9, 1995

http://www.zyvex.com/nanotech/nano4/jeremiahPaper.html


Whither nanotechnology

Overview

Core molecular

manufacturing

capabilities

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Today

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products

Products


Whither nanotechnology

How long?

  • Correct scientific answer: I don’t know

  • Trends in computer hardware suggestive

  • Beyond typical 3-5 year planning horizon

  • Depends on what we do

  • Babbage’s computer designed in 1830’s


Research objectives
Research objectives

Goals

  • Mechanosynthesis

    H abstraction, Carbene insertion, …

  • System design

    assemblers, robotic arms, …


Whither nanotechnology

Nanotechnology offers ... possibilities for health, wealth, and capabilities beyond most past imaginings.

K. Eric Drexler


Whither nanotechnology

Quantum uncertainty wealth, and capabilities beyond most past imaginings.

σ2: positional variance

k: restoring force

m: mass of particle

ħ: Planck’s constant divided by 2π


Whither nanotechnology

Quantum uncertainty wealth, and capabilities beyond most past imaginings.

  • 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


Whither nanotechnology

Molecular mechanics wealth, and capabilities beyond most past imaginings.

  • 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


Whither nanotechnology

Molecular mechanics wealth, and capabilities beyond most past imaginings.

Limitations

  • Limited ability to deal with excited states

  • Tunneling (actually a consequence of the point-mass assumption)

  • Rapid nuclear movements reduce accuracy

  • Large changes in electronic structure caused by small changes in nuclear position reduce accuracy


Whither nanotechnology

Buckyballs wealth, and capabilities beyond most past imaginings.


Whither nanotechnology

Buckytubes wealth, and capabilities beyond most past imaginings.

Fullerenes

SWNT

MWNT

Chirality

Buckminsterfullerenes


Whither nanotechnology

Buckytubes wealth, and capabilities beyond most past imaginings.

What is “chirality?”


Whither nanotechnology

Molecular wealth, and capabilities beyond most past imaginings.

constructor

Molecular

constructor

Molecular

constructor

Broadcast architecture

Macroscopic

computer

http://www.zyvex.com/nanotech/selfRep.html


Nanopores
Nanopores wealth, and capabilities beyond most past imaginings.

Illustration from Harvard Nanopore Group


Millipede
Millipede wealth, and capabilities beyond most past imaginings.

Illustration from IBM Zurich


Whither nanotechnology

wealth, and capabilities beyond most past imaginings.

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Whither nanotechnology

System designs wealth, and capabilities beyond most past imaginings.

System

Sub-system

Sub-system

Sub-system

part

part

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Whither nanotechnology

System designs wealth, and capabilities beyond most past imaginings.

Why don’t we have more system designs?

Development times are 10+ years

Planning horizons are usually 10- years

Research funding focused on “science”

FUD


Whither nanotechnology

What to do wealth, and capabilities beyond most past imaginings.

  • Shorten development times

  • Identify intermediate targets

  • Gain support from groups with long planning horizons

  • Lengthen planning horizons

  • Reduce FUD by detailed design and analysis


Whither nanotechnology

Stiffness wealth, and capabilities beyond most past imaginings.

E: Young’s modulus

k: transverse stiffness

r: radius

L: length


Whither nanotechnology

Stiffness wealth, and capabilities beyond most past imaginings.

E: 1012 N/m2

k: 10 N/m

r: 8 nm

L: 100 nm


Whither nanotechnology

Convergent assembly wealth, and capabilities beyond most past imaginings.


Whither nanotechnology

Convergent assembly wealth, and capabilities beyond most past imaginings.


Whither nanotechnology

Convergent assembly wealth, and capabilities beyond most past imaginings.


Whither nanotechnology

Space wealth, and capabilities beyond most past imaginings.

  • SSTO (Single Stage To Orbit) vehicle

  • 3,000 kg total mass (including fuel)

  • 60 kilogram structural mass

  • 500 kg for four passengers with luggage, air, seating, etc.

  • Liquid oxygen, hydrogen

  • Cost: a few thousand dollars

K. Eric Drexler, Journal of the British Interplanetary Society,

V 45, No 10, pp 401-405 (1992).

Molecular manufacturing for space systems: an overview


An overview of replicating systems for manufacturing
An overview of replicating systems wealth, and capabilities beyond most past imaginings.for manufacturing

Replication

  • Advanced Automation for Space Missions, edited by Robert Freitas and William Gilbreath NASA Conference Publication 2255, 1982

  • A web page with an overview of replication: http://www.zyvex.com/nanotech/selfRep.html