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Whither nanotechnology?

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?

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  1. Whither nanotechnology? Ralph C. Merkle Distinguished Professor of Computing Georgia Tech College of Computing

  2. Web pages www.foresight.org www.zyvex.com/nano www.nano.gov

  3. Health, wealth and atoms

  4. Arranging atoms • Flexibility • Precision • Cost

  5. Richard Feynman,1959 There’s plenty of room at the bottom

  6. 1980’s, 1990’s Experiment and theory First STM By Binnig and Rohrer

  7. 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

  8. The goal Arrangements of atoms . Today

  9. The goal The goal .

  10. Positional assembly

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

  12. Theoretical

  13. Molecular mechanics • Manufacturing is about moving atoms • Molecular mechanics studies the motions of atoms • Molecular mechanics is based on the Born-Oppenheimer approximation

  14. Born-Oppenheimer The carbon nucleus has a mass over 20,000 times that of the electron • Moves slower • Positional uncertainty smaller

  15. 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

  16. Hydrogen molecule: H2 Energy Internuclear distance

  17. Hydrocarbon machines

  18. Molecular machines

  19. Theoretical

  20. Thermal noise σ: mean positional error k: restoring force kb: Boltzmann’s constant T: temperature

  21. Thermal noise σ: 0.02 nm (0.2 Å) k: 10 N/m kb: 1.38 x 10-23 J/K T: 300 K

  22. 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

  23. Making diamond today Illustration courtesy of P1 Diamond Inc.

  24. Hydrogen abstraction tool

  25. Other molecular tools

  26. 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.

  27. Self replication A redwood tree (sequoia sempervirens) 112 meters tall Redwood National Park http://www.zyvex.com/nanotech/selfRep.html

  28. Self replication The Von Neumann architecture Universal Computer Universal Constructor http://www.zyvex.com/nanotech/vonNeumann.html

  29. Self replication Drexler’s proposal for an assembler http://www.foresight.org/UTF/Unbound_LBW/chapt_6.html

  30. Exponential assembly

  31. Convergent assembly

  32. 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

  33. 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)

  34. Impact The impact of a new manufacturing technology depends on what you make

  35. 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

  36. 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, ...

  37. 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/

  38. Impact Size of a robotic arm ~100 nanometers 8-bit computer Mitochondrion ~1-2 by 0.1-0.5 microns

  39. Scale Mitochondrion Size of a robotic arm ~100 nanometers 8-bit computer “Typical” cell: ~20 microns

  40. Provide oxygen

  41. Digest bacteria

  42. Digest bacteria

  43. 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

  44. 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

  45. 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

  46. 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

  47. Research objectives Goals • Mechanosynthesis H abstraction, Carbene insertion, … • System design assemblers, robotic arms, …

  48. Nanotechnology offers ... possibilities for health, wealth, and capabilities beyond most past imaginings. K. Eric Drexler

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

  50. Quantum uncertainty • 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

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