Tuesday, November 4, 2008

Nanotechnology in Nature

Direct Impact and Synergetic Synthesis on Micro/Nano-Particles:

Applications in Today’s Technology

and possibly –

Origin of Primordial Organics in Cold Dark Dust


Benjamin F. DORFMAN

Direct impact by reacting energetic molecules may generate organic and variety of solid carbon forms on the cold substrate. Even more effective is the synergetic thermal-impact activation in the moderate substrate temperature range. Over the past four decades, such energizing mechanism was subject of systematic research, and it is already almost three decades as this technology is industrially used in the USA and many other countries [1].

The major technique currently employed in the technology is remote vacuum plasma. The resulting materials are: the silica-stabilized diamond-like amorphous carbon, the synergetic grapheme-diamond quasi-amorphous carbon, and the carbon-metals diamond-like composites of atomic scale and nano-composites.

But such cold impact synthesis can flow in cosmic space in dark dust clouds (on the surface of micro- and nano-particles) producing primordial organics in the universe over the billions years, while synergetic synthesis of more complex forms is plausible in relatively short living warm clouds.

The vacuum UV specter of synergetic carbon stabilized by silica shows an absorption maximum located in the variable range of 1400,Å to 2600,Å, depending on conditions of synthesis, and at certain condition carbon-silicon matter with famous ‘2175 Å’ astronomic feature [2] may be synthesized as well.

While the artificial synthesis of SSC is based on acceleration of charged particles (atomic and molecular ions) with a bias voltage, the cosmic cause of charge is may be due to radioactive sources, in particular b-decay, i.e. 14C, 36Cl, 26Al, 60Fe, 40K, and in certain space environment – possibly a shorter living 42Ar, 32Si, 39Ar.

Although b-decay is commonly assumed as destructive force for organics, in pre-biotic organic synthesis it could be more properly considered similarly to temperature as a dual {synthesizing ↔ decomposing} source of energy. Indeed, there is indication that a low doses radiation may even enhance DNA thermal stability [3].

There are variety other energizing mechanism revealed in space [4-10]. For instance, possible sources of energy may be due to the stars’ “winds”. Thus, p+ and CO carry energy in solar wind (as a known example) carry up to 4-5 eV; especial effective, could be SiO-wind where it reaches such an energy range.

Direct Impact and Synergetic Synthesis on Micro/Nano-Particles may be significant for both the contemporary technology and the primordial origin of organic world.

The polycyclic aromatic molecules were detected in interstellar dust as early as in 1968, and lately, both aromatic and aliphatic organics detected in proto-planetary and planetary nebulas [4, 11-13]. Still, the basic mechanisms responsible for organics formation in interstellar space remains unknown. It was recently found that a ratio of methyl formate (C2H4O2) to hydrogen in parts of our galaxy is over two orders of magnitudes higher than can be explained even using “the best models” of interstellar chemistry. None of developed concepts based on irradiation from the active stars, or a shock wave, caused by the in-fall or outflow of material in the star-formation process, suggests a self consistent energizing mechanism functioning on a feasible time scale and at the temperature range not exceeding the upper limit of organic stability. Furthermore, the nature of the strongest ultraviolet spectral signature of the interstellar dust - astronomical 2175,Å feature - remains unknown, although over the past 40 years, a variety of materials have been proposed, not excluding nano-diamonds and fullerenes. But recently Lawrence Livermore National Laboratory found that amorphous carbonaceous-silicate matter abundant in interstellar and interplanetary dust may be responsible for the 2175 , Å feature. [14].

Unavoidably, one shall assume a continuous generation of organic and silicon-carbonaceous matter in cold dark interstellar space. Indeed, a frigid (~ 8K) reservoir of simple sugar molecules were very recently discovered in a dust cloud of interstellar space.

In this web publication we briefly discuss the principles of Direct Impact and Synergetic Synthesis in association with its possible role in interstellar “reactors” and the earliest phases of life origin. The complete report was submitted and accepted for international conferences 2005 and 2008, but due to different reasons the Author could not make those reports. This publications is giving a simplified version of that. More details about technology, underlying physics and chemistry, as well practical applications on the land may be found in [1].

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Introduction

Considering technology as a continuation of evolution, and evolution as the natural technology, one would find numerous similarities. The most important of them is correlation between independently developing islands of evolution or cultures. In Nature, it is observed, theorized and accepted as obvious consequence of natural laws, such as evolution of stars, planets, and, if not the life itself because the only one example known so far, but at least of ecosystems and species. In technology, it is especially evident before the era of great discoveries when American and Australian cultures were completely insulated, and even in the early ages – at the very beginning of the humanity when the Middle East – European cultural nuclei and China nucleus were completely separated. One of the major complimentary lines in technological evolution is start from simple impact technology, stone against stone, sharp stone against wood or bone, etc., next - “taming” the fire that was followed with multiple discoveries of thermally activated chemistry in food preparation, artificial stones, e.g. ceramics, and metallurgy, and then discovery of combined thermal-impact technology of forging and glass vessels manufacturing.

There are just a few examples of technologies so greatly served for civilization as metal forging and glass blowing. However, they never considered as the synergy of thermal and mechanical energy but rather as the thermal preconditions for mechanical treatment. Material synthesis, being it realized with metals, glasses or contemporary plastics, is basically chemical technology, while formation of the useful shape is predominantly mechanical treatment - let’s say a “hammer technology”. But what would happen if the hammer miniaturized up to the atomic scale?

Physical-Chemical Background

Indeed, any contemporary material synthesis technology is based on one of three major approaches to chemical reaction activation and inter-atomic bond formation: thermal activation, electro-chemical activation, or impact activation (by incident ions, or neutral atoms or sub-molecular particles). The thermal activation approach continues traditional technology developing over the millenniums, while its basic kinetic law was formulized in 1889 by S. Arrhenius. Electrochemical approach originated with M. Faraday;s works, and its theory was formulized by Arrhenius (1887), Milner (1912), Debye and Huckel (1923), and Onzager (1926). The impact activation approach was developed in the 20th century, and its kinetic law was not considered theoretically because the incident particle energy typically exceeds the chemical barrier by a few orders of magnitude.

But let’s consider relatively low-energetic incident atom or low-molecular radical, ionized or neutral, colliding with solid surface. More specifically, consider incident particle possessing average kinetic energy Ei of about or above the level of activation barrier for typical chemical reactions but not exceeding the elastic threshold of the substrate. Thus, the incident particle would not produce direct structural damage to the subject lattice, but rather a spike of excitation over average thermal energy in substrate kTs.

While singular spike of thermal excitation in lattice is effectively considered as a quasi-particle, or phonon, let’s inversely consider the mechanically induced excitation as quasi-thermal fluctuation. Thus, we can define certain equivalent quasi-temperature T* corresponding to such impact excitations. On one hand, based on statistical physics law underlying the Arrhenius’ formula, one may estimate the frequency of fluctuation E≥ Ei as

The coordination factor N*≥1 reflects dissipation of the incident particle’ energy in the coordination proximity of collision point during characteristic time of the event.

On the other hand, the real frequency of such events is simply the incident flux density expressed in the number of atomic layers per second, w.

Assuming w = f, one would find:

Because this spike corresponds to additional energy above the average thermal oscillation (we assume that below elastic threshold the harmonic approximation is justified), the effective temperature in the spike proximity during characteristic time of the event of about n-1, sec. would be

Teff.= T + T*


Thus, depending on ratio between the substrate temperature and the incident particles energy, one of three major mechanisms may be predominant:

The current technology

The real present technology may be considered as “on-the-land” laboratory.

Figure 1-3 show schematics of remote plasma synthesis of diamond-like and synergetic carbon matter, as well as atomic-scale and nano- metal-carbon composites. The semi-insulated high-density chemical plasma reactor generates energetic “wind” of the simplest carbon- and silica- radicals (typically – positively charged CH+, SiO+ and alike). The radicals are extracted by electrical field and directed to the substrate holder. While colliding with substrates, the energetic radicals overcomes the activation chemical barriers and form diamond-like or synergetic forms of carbon.


Figure 1. A scematic of synthesis

Figure 2. A simplified schematic of internal design.

Figure 3. View of three identical reactors (pilot versions).

Figures 4 and 5 show a schematic model representation of two major carbonaceous-silicate matters produced in such conditions.


Atomic-Scale Composite structure, known as DLN, (and also known as Dylyn™) with density range of 1.9 to 2.25 g/cm(sup.3), while the density range of 2.1 to 2.23 g/cm(sup.3) is the most typical. In DLN the diamond-like network, the graphite-like netrwork and the silica network are partially bonded only, and the entire structure is completely amorphous.

Synergetic diamond-graphene quasi-amorphous carbon (QUASAM™).
These ultra-lightweight [
1.3 to ~1.7 g/cm(sup.3)] materials have a self-organized hierarchical structure from atomic, to nano-, to the micrometer level approaching by its atomic arrangement the utmost physical limit of composite solids. The diamond-like 3D framework interpenetrates and bonds together graphene meso-planes. QUASAM™ is not only superior to conventional DLC, but explores the strongest features of the graphene mesophase (otherwise known only in nanotubes) on macroscopic level as well.

Usually, such forms of carbon, being far remote from the equilibrium states, are unstable, extremely stressed and short-living. In the shown synthesis conditions, the silica component of the “wind” radically changes the situation resulting with formation of carbon-silica composites of atomic scale: interpenetrating atomic-scale networks of carbon and silica. These materials combine many of the best features of both diamond-like and graphite-like (‘graphene’) carbon and may survive over nearly unlimited time (as theoretically estimated; practically tested so far at ‘room temperature”- over quarter of century, while the high temperature tests allows extrapolation over geological time for low-temperature stability).

Figure 6a shows absorption spectra for three major families of these carbon forms [these optical spectra had been obtained by James N. Hilfiker (J.A.Woollam Co, Inc.)].

Figure 6b suggests an interpolation for intermediate states and plausible location of the temperature corresponding to the 2175Å astronomic feature, assumingly due to amorphous carbonaceous-silicate matter abundant in interstellar and interplanetary dust. There are no sharp specific features on the plots but some blunt maximums instead. But this is natural for amorphous solid where any structural feature may be surrounded by different chemical or coordination neighbors. The maximum absorption position is plausibly in linear relation to deposition temperature, and 2175 A may be anticipated at T=~460 C.



Possible implication for astrochemistry

Life is not a ‘technology’, but is based on a balance between continuous processes of synthesis (a natural ‘technology’) and degradation. Synthesis needs a sufficient environmental temperature to overcome chemical barriers, while to sustain under permanent attacks by degradation, the synthesis demands limiting temperature from the top. The suitable temperature range is narrower for more complex life forms. But the critical level of complexity from where the life may start cannot be reached by direct transition for non-organic matter. A rather complex and abounding pre-biotic organic environment should precede the life initiation. This is shown on diagram in some utmost schematic depiction.

Between the greatest challenges of the evolution theory, is extremely fast appearance of life as soon as the Earth was cooled enough at least locally. This implies a much longer (billions years) pre-biotic synthesis. This is possible only in relatively cool interstellar space. But the mechanisms of activation of chemical reactions is such conditions - is another challenge. Direct-impact- and synergetic synthesis itself may not reach the life complexity but may suggest a true mechanism for generation of the pre-biotic cosmic “soil” – starting from the age of a young universe when the early stars produced enough carbon.

On one hand, to establish the basic scale, consider three principle scenarios:








Hence, an atomic scale “hammer” haven being working in synergy with thermal activation appears as the effective mechanism both in technology and in the nature.
The ratio between T*, K values for direct reactions, surface reactions and superficial restructuring is also important: it shows that there are good ranges of values of synergetic parameters {Ei, Ts} where direct reactions would be activated effectively while not damaging the surface or destruct the previously synthesized films, as well as range of {Ei, Ts} where direct reactions and surface reaction may be effectively activated without destroying of the previously synthesized or pre-existed structure.
On the other hand, one may consider three possible scenarios in cosmic space:
Scenario 1.
Dark dust cloud.
The only source of charge are mechanical collisions.
The collision are relatively rare, and electrical charge is weakly depending on the particle size.
The most active are relatively fine particles.
Scenario 2.
Intensive irradiation (from the nearby star or from intrinsic -radioactivity)
The surface density is in the quasi-equilibrium state with respect to media.
The most active are large bodies
Scenario 3, intermediate
Combined source from irradiation and random collisions
Relatively weak irradiation produces a background charge, while relatively rare collisions result with randomly distributed additional charge.
The most active range of particles’ size gradually shifts from fine particles to larger bodies correspondingly to decrease of collisions’ frequency and increase of the irradiation.
To reach some realistic estimates in more quantity terms, one should consider the plausible density of dust particles, their distribution by size and charge and the resulting radius of capture and energy of collision of incident ions with particle vs. the density of active gas in the same clouds.

Omitting here the details, we will give some numbers for orientation:

The smallest particles of about 1 nm radius, even though they may have the highest relative surface density of electrical charge, may generate collision energy not exceeding 10 eV with radius of capture on a few nanometers level. Such particles may play essential role in some special conditions of their density combined with extensive charge generation.

The most active generator of organic matter in space should be particles of a few micrometers range which are able to capture ions from up to a few centimeters, and even nearly 1 m proximity while providing their incident collision with energy up to above 100 eV.

This well corresponds to tipical dense interstellar molecular clouds: density >100 cm-3, T=10-50 K, radius > 1 pc, a gas-to-dust mass ratio ~ 100, dust-to-gas number density ratio ~ 10-12, grain radii usually in the range 0.001-3 micron. [15]

On the other hands, the larger bodies in the range of 1 cm to about 1 m are able to capture ions from a few kilometers proximity and may routinely generate the incident collisions up to 1000 eV level. Combined with low temperature preserving the produced molecules by composition and on the substrate, such celestial bodies may generate rather complex organics, nitrogen derivative of organics such as famous Australian meteorite [16], as well as silicon-carbonious solid matter; over the million years of exposure, they may be completely covered with the secondary-synthesized material and thus self-converted into Carbonaceous chondrites as recently fallen Canadian meteorite [17].

Most importantly for technology, depending on available technique, those “quasi-fluctuations” may be precisely calculated and delivered to the front of new solid growth to overcome specific chemical barriers. Thus, appropriately controlled synergetic conditions allow selective chemical synthesis on solid surface that is hardly possible in conventional technology. The other important features of synergetic synthesis is the possibility to control the growth of nano-crystals or mono-layers while simultaneously and virtually independently controlling the surface chemical reactions. This is due to predominantly thermal activation of cooperative mechanisms of the first kind phase transitions and a local nature of chemical reactions which may be effectively activated by the impact of the incident particles. Thus, synergetic activation is particularly prospective for synthesis of predetermined nano-structured materials. While the ancient thermal technology is restricted by the reverse processes, and the ion/plasma technology, inversely, is usually realized in virtually irreversible conditions, the synergetic synthesis at first allows control of the reverse processes contribution and synthesis of synergetic solids which are not achievable by the prior techniques. Synergetic synthesis is also more effective and requires a lower temperature (typically, ~ 600-800 K) and lower voltage or particle energy (typically, 10 to 100 eV) that is crucial for micro- and nano-electronics.

Kinetic energy of incident particles as low as Ei~10 eV is sufficient to activate the growth of relatively soft “polymer-like” forms of carbon on cold substrate (substrate temperature Ts ≤ 300 K); at Ts ≥500 K - energy Ei ~20÷30 eV is ample for synergetic synthesis of relatively hard carbon forms. Normally, synthesis conducted on the flat substrates; however, in high-frequency or pulse accelerating field, deposition of carbon films is realized on the particles as well.

While the artificial synthesis of SSC is based on acceleration of charged particles (atomic and molecular ions) with a bias voltage, as it mentioned above, the cosmic cause of charge is may be due to radioactive sources, in particular b-decay. One act of decay may destroy a single bond in the absorbed organic layer while generating multiple electrons emitting from the substrate. Not only the resulting electrostatic field will energize the surface reactions, it will also cause the negative ion generation and accretion of such ions from surrounding space on the particles of cosmic dust. With relation to synergetic thermal-impact synthesis, it is important to note that accordingly to recent research, thermal stability of relatively complex bio-organics may essentially increase(see, for instance [18]), and for relatively simple bio-organics - even approach 600K [19].

A rough estimate based on suggested mechanism and general astronomic data suggests a very modest productivity of organics generation in contemporary Solar system, but very high productivity of interstellar dust clouds and convincingly high “domestic” productivity of proto-planetary nebulas.

Depending on the ratio between intensity of b-active background, the particle density in cloud and the carbon-containing gas pressure, the most active particles may vary from ~101-102 nm to relatively large macroscopic size. Such mechanisms may be significant for both the contemporary technology and the primordial origin of organic world - in both interstellar space and the earliest phase of the Earth or other planets formation.

Note in conclusion:

After this article was presented in 2004, it was shown the existence of a new class of astrophysical objects where the self-gravity of the dust is balanced by the force arising from shielded electric fields on the charged dust. [20]. Such an object could be effective astronomic reactor of pre-biotic organic matter.

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Reference:

1. B.F. Dorfman, Stabilized sp2/sp3 Carbon and Metal-Carbon Composites of Atomic Scale as Interface and Surface-Controlling Dielectric and Conducting Materials. In: Handbook of Surfaces and Interfaces of Materials (H. S. Nalwa Ed.), v.1, Academic Press, San Diego, 2001, pp. 447-508.

Also a brief summary at:
http://www.clarkson.edu/camp/reports_publications/dorfman/Dorfman_SynergeticMatter_2005.pdf

2. John Bradley, Zu Rong Dai, Rolf Erni, Nigel Browning, Giles Graham, Peter Weber, Julie Smith, Ian Hutcheon, Hope Ishii, Sasa Bajt, Christine Floss, Frank Stadermann, Scott Sandford. An Astronomical 2175 Å Feature in Interplanetary Dust Particles. Science 14 January 2005: Vol. 307. no. 5707, pp. 244 – 247.
3. Georgakilas AG, Sideris EG, Sakelliou L, Kalfas CA, Low doses of alpha- and gamma-radiation enhance DNA thermal stability. Biophys Chem. 1999 Aug 9;80(2):103-18.
4. Grun, E.; Gustafson, B. A.; Dermott, S.; Fechtig, H., eds. Interplanetary Dust. 2001, Springer: New York.
5. Hansen, D. O., Mass analysis of ions produced by hypervelocity impact. Applied Physics Letters,1968. 13(3): p. 89-91.
6. Abramov, V. I.; Bandura, D. R.; Ivanov, V. P.; Sysoev, A. A., Energy and angular characteristics of ions emitted in the impact of accelerated dust particles on a target. Sov. Tech. Phys. Lett., 1991. 17(3): p. 194-195.
7. Hornung, K. and Kissel, J., On shock wave impact ionization of dust particles. Astronomy and Astrophysics, 1994. 291: p. 324-336.
8. Hornung, K.; Malama, Y. G.; Kestenboim, K. S., Impact vaporization and ionization of cosmic dust particles. Astrophysics and Space Science, 2000. 274: p. 355-363.
9. A. Abergel1, J. P. Bernard, F. Boulanger, D. Cesarsky;E. Falgarone, A. Jones,M.-A. Miville-Deschenes1;M. Perault, J.-L. Puget, M. Huldtgren, A. A. Kaas, L. Nordh,G. Olofsson, P. Andre, S. Bontemps, M. M. Casali11, C. J. Cesarsky, M. E. Copet, J. Davies,T. Montmerle, P. Persi, and F. Sibille. Evolution of very small particles in the southern part of Orion B observed by ISOCAM. Astronomy & Astrophysics. 389, 239-251 (2002).
10. Kimura, H. and Mann, I., The electric charging of interstellar dust in the solar system and consequences for its dynamics. Astrophysical Journal, 1998. 499(454-462).
11. Zinner, E., Stellar nucleosynthesis and the isotopic composition of presolar grains from primitive
meteorites. Annual Review of Earth and Planetary Sciences, 1998. 26: p. 147-188.
12. Sun Kwok, "The synthesis of organic and inorganic compounds in evolved stars", p 985-991 v 430, Nature, 26 Aug 2004.
13. C. S. Contreras, J.-F. Desmurs, V. Bujarrabal, F. Colomer, J. Alcolea, 2002, Astronomy & Astrophysics., 385, L1-L4.
14. John Bradley, Zu Rong Dai, Rolf Erni, Nigel Browning, Giles Graham, Peter Weber, Julie Smith, Ian Hutcheon, Hope Ishii, Sasa Bajt, Christine Floss, Frank Stadermann, Scott Sandford. An Astronomical 2175 Å Feature in Interplanetary Dust Particles. Science, 14 January 2005: Vol. 307. no. 5707, pp. 244 – 247.
15. Yeghikyan A. G.; Fahr H. J.; Annales geophysicae, 2003, vol. 21, no 6 (177 p.)]
16. Shock E.L., and Schulte M.D., Summary and implications of reported amino acid concentrations in the Murchison Meteorite. Geochimica et Cosmochimica Acta 1990, vol. 54, pp. 3159-3173.],
17. Science Daily (Aug. 27, 2001)].
18. Ueda, Tadashi; Masumoto, Kiyonari; Ishibashi, Ryoji; So, Takanori. Remarkable thermal stability of doubly intramolecularly cross-linked hen lysozyme. Protein Engineering, Volume 13, Number 3, March 2000 , pp. 193-196(4), Oxford University Press.
19. Michael C. Adams, Joseph N. Moore, Laszlo G. Fabry, and Jong-Hong Ahn, Thermal stabilities of aromatic acids as geothermal tracers. University of Utah Research Institute. Salt Lake City.
20. K. Avinash, and P. K. Shukla, Gravitational equilibrium and the mass limit for dust clouds. New J. Phys. 8 (2006) 002.


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