1 There’s Nothing Small about Nanotechnology Ralph C. Merkle Xerox PARC

2 See for an index of talks

3 The best technical introduction to molecular nanotechnology: Nanosystems by K. Eric Drexler, Wiley 1992

4 Sixth Foresight Conference on Molecular Nanotechnology November Santa Clara, CA

5 Seventh Elba-Foresight Conference on Nanotechnology April, 1999 Rome, Italy

6 Manufactured products are made from atoms. The properties of those products depend on how those atoms are arranged.

7 Coal Sand Dirt, water and air Diamonds Computer chips Grass It matters how atoms are arranged

8 Today’s manufacturing methods move atoms in great thundering statistical herds Casting Grinding Welding Sintering Lithography

9 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,

10 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

11 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)

12 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

13 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

14 Quantum positional uncertainty in the ground state σ 2 :positional variance k: restoring force m: mass of particle ħ :Planck’s constant divided by 2 π

15 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

16 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

17 Example: H 2 Internuclear distance Energy

18 Molecular mechanics Internuclear distance for bonds Angle (as in H 2 O) Torsion (rotation about a bond, C 2 H 6 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

19 Possible arrangements of atoms. What we can make today (not to scale)

20 The goal of molecular nanotechnology: a healthy bite..

21 What we can make today (not to scale). We don’t have molecular manufacturing today. We must develop fundamentally new capabilities. Molecular Manufacturing

22 Core molecular manufacturing capabilities Today Products Overview of the development of molecular nanotechnology

23 Two more fundamental ideas Self replication (for low cost)Self replication Programmable positional control (to make molecular parts go where we want them to go)Programmable positional control

24 Von Neumann architecture for a self replicating system Universal Computer Universal Constructor

25 Drexler’s architecture for an assembler Molecular computer Molecular constructor Positional deviceTip chemistry

26 Illustration of an assembler

27 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

28 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:

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

30 C program 808 Von Neumann's universal constructor500,000 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 Complexity of self replicating systems (bits)

31 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)

32 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

33 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

34 Developmental pathways Scanning probe microscopy Self assembly Hybrid approaches

35 Moving molecules with an SPM (Gimzewski et al.)

36 Self assembled DNA octahedron (Seeman)

37 DNA on an SPM tip (Lee et al.)

38 Buckytubes (Tough, well defined)

39 Bucky tube glued to SPM tip (Dai et al.)

40 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.

41 Diamond Physical Properties PropertyDiamond’s valueComments Chemical reactivityExtremely low Hardness (kg/mm2)9000CBN: 4500 SiC: 4000 Thermal conductivity (W/cm-K)20Ag: 4.3 Cu: 4.0 Tensile strength (pascals)3.5 x 10 9 (natural)10 11 (theoretical) Compressive strength (pascals)10 11 (natural)5 x (theoretical) Band gap (ev)5.5Si: 1.1 GaAs: 1.4 Resistivity (W-cm)10 16 (natural) Density (gm/cm3)3.51 Thermal Expansion Coeff (K-1)0.8 x 10-6SiO2: 0.5 x 10-6 Refractive 590 nmGlass: Coeff. of Friction0.05 (dry)Teflon: 0.05 Source: Crystallume

42 A hydrocarbon bearing

43 A planetary gear

44 A proposal for a molecular positional devicemolecular positional device

45 Classical uncertainty σ:mean positional error k: restoring force k b : Boltzmann’s constant T:temperature

46 A numerical example of classical uncertainty σ:0.02 nm (0.2 Å) k: 10 N/m k b : 1.38 x J/K T:300 K

47 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.

48 Synthesis of diamond today: diamond CVD diamond CVD Carbon: methane (ethane, acetylene...) Hydrogen: H 2 Add energy, producing CH 3, H, etc. Growth of a diamond film. The right chemistry, but little control over the site of reactions or exactly what is synthesized.

49 A hydrogen abstraction tool

50 Some other molecular tools

51 A synthetic strategyA 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

52 The impact of molecular manufacturing depends on what’s being manufactured Computers Space Exploration Medicine Military Energy, Transportation, etc.

53 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 bits in the same volume Or more than a billion Pentiums operating in parallel

54 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 ogy/publications/1997/applications/

55 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)

56 Disease and illness are caused largely by damage at the molecular and cellular level Today’s surgical tools are huge and imprecise in comparison nanotechAndMedicine.html

57 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.

58 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

59 Cryonics 37 º C -196 º C (77 Kelvins) Freeze Revive Time Temperature (~ 50 to 150 years)

60 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?

61 Today’s choice: would you rather join The control group (no action required)? Or the experimental group (contact Alcor:

62 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,

63 Environmental impact depends on Population Living standards Technology

64 Molecular nanotechnology and the environment Low cost greenhouse agriculture Low cost solar power Pollution free manufacturing The ultimate in recycling

65 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

66 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 CO 2 in the air

67 The best way to predict the future is to invent it. Alan Kay