There are several chemical methods to synthesize nanoparticles of gold, silver, and iron oxide, as co-precipitation or thermal decomposition. But physical methods either are not widely known or publicized. There is the laser ablation in a liquid medium, which can obtain any type of nanoparticles, but lasers for this technique are expensive. Does anyone know a way to make it cheaper or other physical process to obtain nanoparticles?
There are in fact a large variety of physical techniques, many of which have been already described in earlier answers. The typical 'top-down' approach is high energy ball milling, which can yield sub-10nm particles. But the major drawbacks are surface contamination and introduction of structural defects.
The 'bottom-up' variety of physical techniques can be classsified into the following two categories:
(1) Spray techniques such as spray dry, freeze dry, plasma spray and hot spray.
(2) PVD-based techniques are particularly suitable for obtaining nanocrystalline thin films. They include Evaporation-Condensation, CVD and PE-CVD, Laser Ablation and Magnetron Sputtering. Of these, the last is by far the most versatile. One can obtain nanocrystalline films of most metals (dc sputter), oxides, nitrides, sulphides etc. (rf sputter) either using reactive sputtering or from targets having the same composition. Low substrate temperatures, high sputter-gas pressure and low energy conditions generally favour smaller particles. But if you are looking for a cheaper technique without sophisticated instruments, chemical techniques are better and provide larger yield.
Several reviews are available on this topic. Some representative references are added below (I have chosen older references that give more details).
1. SPUTTERING: (i) Hahn & Averback, JAP 67 (1990) 1113, (ii) Ayyub et al., Appl Phys A 73 (2001) 67; Scr. Mat, 44 (2001) 1915
2. LASER ABLATION: (i) Koshizaki et al. J Phys Chem B 107 (2003) 9220; Appl Phys A 76 (2003) 641
3.SPRAY DRYING: Okuyama et al. Chem Engg Sci. 58 (2003) 537.
4. INERT GAS CONDENSATION: Siegel et al. J. Mat. Res. 6 (1991) 1012.
You can, indeed, produce nano particles by mechanical attrition, I.e., high energy milling. This can be a pure physical process of size reduction by mechanical and thermal stress, or it can involve mixed physical and chemical nano particle formation in the case of reactive milling.
For materials which are not friable enough for reducing its size to the nano level by attrition, cryogenic milling is an option, with a LN slurry and zirconia balls in a high energy mill with ceramic lining. Not a cheap option either, but more productive than most laser based processes.
The main problem with mechanical nano particle production is that it results in very broad size distribution, with little control on the dominant size and shape. Laser produces better results, and chemical processes the better ones, in terms of size disperssion.
Any aerosol pyrolysis procedure allows the synthesis of nanoparticles. Of course, you will need to prepare an aerosol of small drops of a precursor in liquid state, transport them through a heating element (usually a tubular furnace) for the pyrolysis and collect the nanoparticles using an adequate filtering device. Production rates and yields are usually large depending on the material and the heating conditions. Moreover, since aerosol drops are chemically homogeneous, the composition of synthesized nanoparticles is also homogeneous. Drawbacks (of course you'll find some) are commonly related to heterogeneities in nanoparticle sizes and shapes.
Literature is plenty with materials synthesized using these methods, from inorganic oxides to metal nanoparticles. A good starting point would be the book of Kodas and Hampden-Smith (http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0471246697.html)
The availability of an alternative method for obtaining "nanoparticles" depends on what you mean by "nanoparticles" and what you really want to obtain!
Physical methods are usually more "dirty" than chemical ones as they are "top down" versus "bottom up" i.e. you reduce the size of a larger object. So you have less control on the shape and size distribution and the smallest size you obtain is usually much larger than the one obtained via chemistry.
I would not classify mechanical methods together with the physical ones (I usually tell my students that you have chemical, physical and mechanical methods), as the processes involved are usually quite different (in the mechanical you don't get through solution, liquid or gas phases). Those are well known and employed in industry for comminution (both batch and continous processes) and can provide a nanostructured powder. However don't expect to be able to produce in a cheap way e.g. well separated and clean cube-shaped Au particles. You can cheaply produce large quantities of powder with (in most cases) some contamination, with a reasonably fine size of aggregate grains containing nano-sized domains.Be warned that the quantity of defects of those powders can be extremely large (you have extreme cold-working), versus very very low values in chemically synthesised powders. With physical methods (e.g. ablation and aerosol already mentioned), the quantity of defects is usualy intermediate (you find more stacking faults vs. dislocations)
Laser ablation (pulsed laser deposition) has been widely used since end of 80s to produce metal and semiconductor nanoparticles on different kind of substrates.
J. Appl. Phys. 109, 094302 (2011)
Phys. Rev. B 79, 235409 (2009)
J. Appl. Phys. 100, 084311 (2006)
Phys. Rev. B, 71, 125420 (2005)
and references therein.
The answer depends much on your nanoparticles, i.e. their chemistry
For instance, in case of noble metal particles, those are effectively prepared by laser ablation in liquid media. Laser ablation of solid metal particles in Ar may also give metal nanoparticles, even for active metals (if Ar atmosphere is pure enough).
Moreover, laser ablation in liquid can also produce some other , more complex nanoparticles, like metal oxide or sulphide ones:
Adv. Funct. Mater., (#7) 22 (2012) 1333-1353.
J. Am. Chem. Soc. (#28) 132 (2010) 9814-9819.
Langmuir (#22) 26 (2010) 16652-16657.
But in this case, chemical reactions are involved, so this is not a purely physical approach.
using DC sputter deposition with gas aggregation/ particle size control by mass filter
I have used the physical vapor deposition method. This way, a metal ball is placed in a tungsten basket which is then vaporized by resistive heating. We have published papers on that in P.R. Griffiths group(University of Idaho). The drawback is that this method is probably limited to metal nanoparticles.
If you want regular hexagonal arrangement of metal nanoparticles on silicon, deposit an intermediate close pack monolayer of polystyrene (PS), then RIE etching a bit, deposit (sputter, evaporation) a thin metal layer, annealing. The distance depends on PS diameter, the nanoparticles sizes depend on initial metal thickness, annealing temperature and time.
Yes, as long as the particles are non-metallic, microwave plasma synthesis is by far the best process. See papers of Vollath et al.
In my department they use RF plasma torches.
Take a look to this project http://www.simba-project.eu/
metal nanoparticles (both pure and alloys) can be obtained via spark generators (also semiconductors, if doped), There are also flame based techniques (e.g. soot/carbon black), and 'glowing wire' generators, basically the wire evaporates and the metal vapor condenses. Maybe you should check papers by my colleague Andreas Schmidt-Ott who is an expert on aerosol NP production and characterisation.
everybody is talking about "the best method" or give links to specific papers/applications. That's great to have an idea, but remember there is no best method here! Each of the proposed methods has advantages and disadvantages and they provide completely different microstructure. So the suggestion is: check what you want to obtain in terms of microstructure and then browse the literature to find what's best suitable to get it!
Laser decomposition, thermal decomposition, photo decomposition, electrode deposition are the normally followed way to obtain nanoparticles.
There are in fact a large variety of physical techniques, many of which have been already described in earlier answers. The typical 'top-down' approach is high energy ball milling, which can yield sub-10nm particles. But the major drawbacks are surface contamination and introduction of structural defects.
The 'bottom-up' variety of physical techniques can be classsified into the following two categories:
(1) Spray techniques such as spray dry, freeze dry, plasma spray and hot spray.
(2) PVD-based techniques are particularly suitable for obtaining nanocrystalline thin films. They include Evaporation-Condensation, CVD and PE-CVD, Laser Ablation and Magnetron Sputtering. Of these, the last is by far the most versatile. One can obtain nanocrystalline films of most metals (dc sputter), oxides, nitrides, sulphides etc. (rf sputter) either using reactive sputtering or from targets having the same composition. Low substrate temperatures, high sputter-gas pressure and low energy conditions generally favour smaller particles. But if you are looking for a cheaper technique without sophisticated instruments, chemical techniques are better and provide larger yield.
Several reviews are available on this topic. Some representative references are added below (I have chosen older references that give more details).
1. SPUTTERING: (i) Hahn & Averback, JAP 67 (1990) 1113, (ii) Ayyub et al., Appl Phys A 73 (2001) 67; Scr. Mat, 44 (2001) 1915
2. LASER ABLATION: (i) Koshizaki et al. J Phys Chem B 107 (2003) 9220; Appl Phys A 76 (2003) 641
3.SPRAY DRYING: Okuyama et al. Chem Engg Sci. 58 (2003) 537.
4. INERT GAS CONDENSATION: Siegel et al. J. Mat. Res. 6 (1991) 1012.
The gas aggregation sources or ion cluster sources are ideal to generate nanoparticles of controlled size. We recently developed a new kind of ion cluster source that allows also the fine tune of the chemical composition of the fabricated nanoparticles. I you want, you can find more information at Langmuir 28, 11241−11249 (2012). However this is not a “cheap” method to generate nanoparticles. The cheapest way would be probably the ball milling.
see
https://www.researchgate.net/publication/227044995_Plasma-Assisted_Deposition_of_AuSiO2_Multi-layers_as_Surface_Plasmon_Resonance-Based_Red-Colored_Coatings
&
http://link.springer.com/article/10.1007%2Fs12274-012-0236-z
Article Plasma-Assisted Deposition of Au/SiO 2 Multilayers as Surfac...
You can try ball milling, also you can try intercalation process which I have already applied and its result was amazing to get nanoparticles, even after leaving the intercalates in open air.
look st these papers:
Rev.Adv.Mater.Sci. 18(2008) 760-76
and
Journal of Alloys and Compounds 434–435 (2007) 655–658
My best regards,
Leszek Stobinski
There are different methods are available for getting nanosized materials by physical methods such as magnetron sputtering (Both RF and DC), plused magnetron sputtering, thermal evaporation technique, spray pyrolysis technique, electrophroteic deposition technique, laser ablation technique, gas phase physical and chemical technique, arc melting process, wire electrical explosion, hot wall tubular reactor, laser pyrolysis/photo thermal synthesis, thermal plasma synthesis, flame synthesis and vapor phase growth (floating catalyst) reactors etc., you have to best choice of you experiments
Prepare uniform aerosols droplets of solutions
of compounds of interest and vaporize thr solvent. There are numerous examples available. Check publications from my lab.
Please visit http://www.iam.kit.edu/wpt/english/535.php
They use a microwave plasma process for nanoparticle synthesis
We tried high energy ball milling for oxide nanoparticles such as LSMO manganites and ferrites, it worked well.
A "physical" method is surely by cluster deposition. Some more information can be found on P. Jensen Review of Modern Physics 71 (1999) 1695 or C. Binns Surface Science Reports 44 (2001) 1
There are several of them depending on the nature of your material, e.g. wet media milling; emulsion-diffusion, hot-melt emulsification + fl;ash cooling, high pressure homogenization, high shear mixing etc.
To get nanoparticles of gold and silver, simple gas evaporation method (R. Uyeda, J. Cryst. Growth 24/25, 69 (1974). ; R. Uyeda, J. Cryst. Growth 45, 485 (1978)) should be applied by using tungusten basket heater. About iron oxide nanoparticles I am not sure.
If you want thin layers the dewetting of sputtered layers also leads to nano particles, e.g.
"Gold Nano-Particles Fixed on Glass"
"Optical Properties of Self Assembled Oriented Island Evolution of Ultra-Thin Gold Layers"
If you can live with a polydisperse aerosol you can use a medical nebuliser with a salt solution. If the solution is low concentration the particle size distribution will end up typically between 50 nm. These are to some extent polydispers but not water soluble (made from charcoal)
Drawback is that all of these will give you water soluble particles.
Hope, there is a comprehensive documentation of all these techniques. Reference requested, please.
Combustion method also is better for preparation nanoparticles, but required high tem. Annealing
For oxide compound, i think flame combustion method is the best. you can get 1 kg nano particle in 2- 3 hours with particle size < 100 nanometre. I read this information from a doctoral thesis of some one. The temperature of the flame reach 2500-3000oC,
Chemistry is surely a subset of physics so why are we being so distinctive? There are many ways to make nano things, physical, chemical, geological, atmospheric & spontaneous. Light a candle (romantic or otherwise) and start breathing C- nanoparticles. They are not special or unusual or new.
Almost all the methods are covered by the respondents. Now you can choose what and how to do it.
Microwave assisted hydrothermal synthesis from sulphate or chlorine precursors. Fast cheap and low temperature !
One needs to get the highly supersaturated vapor, i.e. the near spinodal conditions need to be reached for nanoparticle generation. Topologies of the nucleation rate surfaces are helpful to use for that problem solution. Examples of these topologies can be seen for example in article Michael P. Anisimov, Elena G. Fominykh, Sergey V. Akimov, Philip K. Hopke. Vapor-Gas/Liquid Nucleation Experiments: A Review of the Challenges. J. Aerosol Sci. 40, 733-746, 2009. The article by L.-E. Magnusson, M.P. Anisimov, J.A. Koropchak. Evidence for sub-3 nanometer neutralized particle detection using glycerol as a condensing fluid. J. Aerosol Sci. 2010, V. 41, pp. 637-654 presents a scheme of sub 3 nm particles generation. A flow diffusion chamber can be used as well. Description of it can be found in article by M.P. Anisimov. History of the Flow Diffusion Chamber Development. In Aerosol Science and Technology: History and Reviews. Ed. D.S. Ensor. RTI Press. Research Triangle Park, NC, USA. 2011, P. 457-469.
You may want to try starting with carbonyls for transition metals and some of the noble metals that are traditionally available as carbonyls. They remain in zero oxidation state and can be easily thermally decomplosed and sublimed onto cold surfaces in a static vacuum. If you want clusters of metals, start with polynuclear metal complexes. Iron is a good example, with FeCO5. Fe2CO9, and Fe3CO12. Gold and silver may not be available as multinuclear carbonyls, But others like Rh are.
Copper nanoparticles were produced by laser ablation. See for example,
Eastman, "Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles ,"Appl. Phys. Lett. 78, 718 (2001); http://dx.doi.org/10.1063/1.1341218.
I think that there is highly effective and cheap physicaa method method: Low Pressure Spray Pyrolysis . At low pressure condition (~40 tor) femtolite droplets of auequous solution fastly evaporate. Subsequently, a supersaturation solution appear in droplet. then nucleation start and finally you have a solid nanoparticles. Referencescan be easily found.
Irradiation with low power lasers in gel environment may be the most cheap physical method to obtain nanoparticles from the 3+ and 4+ doped materials
Nano-crystal preparation using physical methods will largely depends on the nature of materials. In general nano-crystals preparations using physical methods will vary from metallic, organo-metalic, inorgaincs and organic molecules. For organic materials, high energy wet ball milling and high pressure homogenizer could be used as physical methods. However, nano-emulsion-solvent evaporation, spray drying, controlled crystallization, non-solvent addition and many more methods have been developed for organic nanocrystals.
Nice to interact with the researchers in the area of 'Nanotechnology'. The above discussions would certainly be aiding me to coordinate with nano biotechnology pertaining to nqanosensor/enzyme sensor studies.
As discussed by other members, there are many methods to obtain nano particles of a diversity of materials, both using physical evaporation and chemical transformation methods. Decomposition of an organometallic precursor to obtain metal nanoparticles or other types of nano structures, such as nano foams, is definitely different from a "physical" method, such as PVD. In the case of Pulsed Laser Deposition (PLD) and plasma-based methods, the difference between "Chemical" and "Physical" is not so clear, since an intense interaction takes place with electrons in the target material, and chemical bonds (in the mind of the chemist) are essentially made of electrons at specific energy levels. In any case, Laser ablation methods may be more economic and offer higher yield than vacuum methods, particularly when irradiating targets under liquids. A distinction must be made, however, between nanosecond and femtosecond pulsed lasers, since the latter are far more expensive (more so than a vacuum apparatus). Further discussion would be convenient on this point, since the ablation mechanisms and resultant products are quite different between these time regimes (ns vs.fs). In order to not extend this discussion, if anyone is interested, we can contribute with further comments of how they affect nano particle and nanostructure preparation.
Yes BALL MILLING is one such most popular method to get nano particles.
The method of evaporation by a pulsed electron beam in gas of low pressure or in vacuum allows to receive
nanoparticles any oxides with the size of particles from 2 up to 10 nm. Usual gathering nanoparticles-1-5 g/hour.
Look, please, article S.Yu. Sokovnin, V.G. Il’ves // Production of nanopowders of metal oxides using pulsed electron beam in low pressure gas / http://www.isrn.com/journals/nanomaterials/2012/504634/
Depending on the substance, RESS technique may work for you (RESS = rapid expansion of supercritical solution): One dissolves the material in supercritical CO2, propane, water (whatever is appropriate) and expand it through a narrow nozzle. Depending on the path through the phase diagram that the expansion takes, one may even different particle shapes.
Of course PLD technique is more economic but still Ball miling is have more monodispersity except possibility of contamination.
Ball mill is common method to prepare nano particle through physical techniques but it time consuming method
Microfluidic processing can be helpful to produce nano particles of certain materials.
Hi Vinayak, can you share some literature on microfluidic processing? This is new to me. Thanks.
I think a nice method developed by a group in the Universidade Federal do Rio Grande do Sul, near your University, is the sputtering deposition of metal nanoparticles, as you can read here http://pubs.rsc.org/en/content/articlelanding/2010/cc/c0cc01353f
They use ionic liquids in another paper. http://pubs.rsc.org/en/Content/ArticleLanding/2011/CP/c1cp21406c
Nice physical method.
I have written a book " Nanotechnology for Surface Coatings" which covers several methods for production of nano particles. The book covers general concepts in detail for nanomaterials and then goes on to discuss applications to coatings. Visit my website: www.coatingsys.com.
I am attaching herewith the excerpt from my book on microfluidic processing.
Another physical technique to be used in conjunction with the Intensive media mills is centrifugation. The mills like the ball mill and attritors produce a distribution of fine particles dispersed in a fluid. If this is followed by an optimised centrifugation (Ultra?), the coarser micro particles will settle out leaving the nano particles in the suspended & dispersed form.
By ball milling you can hardly obtain metal nanoparticles, especially possessing low melting point. Common physical methods are plasma evaporation-condensation, wire explosion technique and Gen-Miller method (drop of metal is blown y stream of inert or reacting gas and nanoparticles are blown off).
yes you could by rias the potential difference between the liquir say ( TiO2)and the precipitated sheet by from 10000 to 15000 volt
There are many physical techniques to prepare nano-structured materials:
1. quantum dots on semiconductor by ion sputtering: S. Facsko, T. Dekorsy, C. Koerdt, C. Trappe, H. Kurz, A. Vogt, H. L. Hartnagel, Formation of Ordered Nanoscale Semiconductor Dots by Ion Sputtering, Science 285 (1999), 5433, pp. 1551-1553
2. nano-wire, nano-particles, etc., inside glasses, semiconductors and etc.
by high energy ion implantation: a lot of publications.
Many are there but depending your laboratory facility and understanding you have to select any one out of them.
I have never done it but surely seen also even about microwave nanoparticles formation, but have no idea - just simple and cheap as you asked...
Dear Alexandre,
Yes you are correct and one can go for that also.
All the above statements are quite convincing and would certainly be beneficial to all concerns.
For silver or gold nanoparticle synthesis the Evanoff and Chumanov method can be employed. It requires slightly elevated temperature and pressure (60-70 deg. C, 1.5 atm H2 gas). Oxides of the metal is used as a precursor and is reduced by the hydrogen gas. This results in chemical-free nanoparticles of an average size of 50nm for a 7 hr synthesis. The diameter is a function of synthesis time with the smaller particles measured to be ~30nm.
I am including the references to the original synthesis papers as well as a more recent paper which employed the Evanoff/Chumanov method.
Evanoff, D. D.; Chumanov, G. J. Phys. Chem. B 2004, 108, 13957.
Evanoff, D. D.; Chumanov, G. J. Phys. Chem. B 2004, 108, 13948.
Merga, Getahun, et al. J. Phys. Chem. C 2010, 114, 14811–14818
Palas has a spark generator for which you can change the elektrodes to produce different types off nanoparticles at high concentrations in air. We have used this for carbon and gold particles but other metals can be used as well
In addition to dr Flemming Cassee's contribution, I'd like to mention that we have used the so-called exploding wire technique with which we could produce large quatities of very odd materials. This depended on the oxygen percentage of the air used.
PLASMA deposition is also one method for synthesizing nano particles by physical methods under controlled conditions.
I just remembered that simple heating of wires also works for some metals: for instance silver is used as a reproducible aerosol as a reference material. I think it can be found in textbooks on aerosol prodcution (by Liu et al.)
There are lot of physical methods for synthesizing the nanooparticles such as laser ablation, vacuum vapor deposition, gamma radiolysis, high energy ball milling, falme spray pyrolysis etc. but the quality of the nanoparticles synthesized from these physical methods are not as good as synthesized by chemical methods
@Aabid Shaik : I appreciate your statement that is quite convincing to me and hopefully should be others too.
Laser ablation is better because it can generate high purity of particles without any contamination.. however low production yield..
You can use to obtaine nanoparticle high temperature tube furnace. You can find detail phys. stat. sol. (c) 4, No. 2, 244– 247 (2007) / DOI 10.1002/pssc.200673263
As stated by Aabid Shaik, there are a lot of physical methods for the synthesis of nanoparticles.
However I would add that the “quality” of the nanoparticles depends pretty much on the application. Some applications do not need single crystal nanoparticles for example. For some applications polycrystalline nanoparticles might be of poor quality while they are perfect for other applications. The same holds for the size and purity of the nanoparticles.
Also, I think that chemical and physical methods are complementary and that the quality of nanoparticles generated by gas aggregation sources or ion cluster sources is very high in terms of crystallinity and purity.
The most simplest and cheapest way to give narrow particles of gold or silver metal is to use evaporation at low vacumn like sputter. The particle size depends on the mean free path of the evaporated atoms. Pressure arround milliTorr range will deliver your request. Howvever, the distance the substrate be placed determining the throughput if the particles are to be coated on. In addition, this gives you a sponge-like structure under SEM, becasue of Van der Waals force. It is alos look like black, conventionally called gold black or silver black, or ....
You have to try and learn to get the process conditions for your target.
Nice to see discussion of many researchers working on nanoparticles. this discussion is very useful to others too. i just want to add some points. there are many methods for synthesis of nanoparticles with various synthesis techniques, some are very easy and simple. every one has its own advantages and disadvantages. size and morphology is influenced greatly by method used. here are some suggestion for you.
(i) Hahn & Averback, JAP 67 (1990) 1113,
(ii) Koshizaki et al. J Phys Chem B 107 (2003) 9220
(iii) Siegel et al. J. Mat. Res. 6 (1991) 1012.
In deed, very interacting post are visible on this forum, and altogether those would certainly be convincing the principal questioner. Hoping for the best.
Kai, apologyTypo
I meant laser ablation; I am not in skin-care
You are right, decompostion is a chemical process, but not wet-chemical and very simple (to be mean: it can eveb be done in a physics lab; however the carbonyls are toxic?!)
Yes, they are very toxic (see: http://en.wikipedia.org/wiki/Metal_carbonyl)
however they are very useful
Read attached publication
Article The effect of gold nanoparticle colloidal solution on perfor...
Many such protocols are there for synthesize but one has to select to achieve his goal.
Many protocols are there but one has to select the proper one to achieve his/her goal.
@ Dillip Bisoyi: You are absolutely right. Of course, an individual should go for hit and trial methodology in view of assessing the merit of the methods to further adopt.
.. when those threads become too long, we enter into loops.. :D
Dec 10, 2012, I gave this answer:
everybody is talking about "the best method" or give links to specific papers/applications. That's great to have an idea, but remember there is no best method here! Each of the proposed methods has advantages and disadvantages and they provide completely different microstructure. So the suggestion is: check what you want to obtain in terms of microstructure and then browse the literature to find what's best suitable to get it!
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