Unveiling Nanotechnology Wonders

1. There’s Nothing Small about Nanotechnologyhttp://nano.xerox.com/nano Ralph C. Merkle Xerox PARC www.merkle.com

2. Seehttp://nano.xerox.com/nanotech/talksfor 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 NanotechnologyNovember 12-15Santa Clara, CAwww.foresight.org/Conferences

5. Seventh Elba-Foresight Conference on NanotechnologyApril, 1999Rome, Italywww.foresight.org/Conferences

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 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

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) http://nano.xerox.com/nano

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 σ2: positional variance k: restoring force m: mass of particle ħ: Planck’s constant divided by 2π

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: H2 Energy Internuclear distance

18. 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

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

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

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

22. 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

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

24. Von Neumann architecture for a self replicating system Universal Computer Universal Constructor http://nano.xerox.com/nanotech/vonNeumann.html

25. Drexler’s architecture for an assembler Molecular computer Molecular constructor Positional device Tip chemistry

26. Illustration of an assembler http://www.foresight.org/UTF/Unbound_LBW/chapt_6.html

27. 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

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

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

30. Complexity of self replicating systems (bits) • C program 808 • Von Neumann's universal constructor 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

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.) http://www.zurich.ibm.com/News/Molecule/

36. Self assembled DNA octahedron(Seeman) http://seemanlab4.chem.nyu.edu/nano-oct.html

37. DNA on an SPM tip(Lee et al.) http://stm2.nrl.navy.mil/1994scie/1994scie.html

38. Buckytubes(Tough, well defined)

39. Bucky tube glued to SPM tip(Dai et al.) http://cnst.rice.edu/TIPS_rev.htm

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 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

42. A hydrocarbon bearing http://nano.xerox.com/nanotech/bearingProof.html

43. A planetary gear http://nano.xerox.com/nanotech/gearAndCasing.html

44. A proposal for a molecular positional device

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

46. 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

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 • 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.

49. A hydrogen abstraction tool http://nano.xerox.com/nanotech/Habs/Habs.html

50. Some other molecular tools