Nano Research - Science topic

Roshan Kumar Singh and Jürgen Weippert Thank you for your reply

The optimal concentration of nanoparticles in nanofluids for battery cooling depends on the trade-off between the enhanced heat transfer and the increased pumping power required to circulate the nanofluid. Generally, higher concentrations of nanoparticles result in higher heat transfer coefficients, but also higher pressure drops and pumping power. Therefore, it is important to choose a suitable concentration that can achieve a balance between these factors. Concentrations ranging from 0.5% to 5% volume fraction can provide significant improvements in heat transfer without excessive penalties in pumping power for battery cooling applications

Hello!

I'm trying to synthesize zero valent iron nanoparticles. We carry out all the synthesis in an inert atmosphere and use PVP to help with stability, but when drying, they oxidize. Tried by lyophilization and oven. Do you have any tips for drying time?

how to prepare zinc sulphate nanoparticles from plants

@ Yasir, yes you have to do the calcination step in ZnO NPs synthesis but when you are preparing ZnO-Ag nanohybrid , I think it is better to dry it as Ag agglomerates at high temperature.

The study of the interaction of nanoparticles (NPs) with proteins is of great importance due to its relevance in several fields including nano-biosafety, nano-bioscience, nano-biomedicine, and nano-biotechnology. an introduction and a discussion of merits of fluorescent NPs compared to molecular fluorophores, labels and probes, the article assesses the kinds and specific features of nanomaterials often used in bioimaging. These include fluorescently doped silicas and sol–gels, hydrophilic polymers (hydrogels), hydrophobic organic polymers, semiconducting polymer dots, quantum dots, carbon dots, other carbonaceous nanomaterials, upconversion NPs, noble metal NPs (mainly gold and silver), various other nanomaterials, and dendrimers. Another section covers coatings and methods for surface modification of NPs..

I wish that there was an easy answer. TEM is probably the best absolute measurement approach, but it requires being careful about statistics, and being aware of artifacts associated with drying the sample. DLS is in principle better for hydrated systems but at high ionic strength aggregation is likely. The tradeoffs are presented well here:

Also check https://www.ibiology.org/talks/fluorescent-probes/

use can use hydrothermal synthesis technique.

We provide researchers with low-cost mild- and hard- anodized AAO templates with different pore lengths and diameters. Contact: amirh.montazer@gmail.com

If you want lavendar-colored plasma, your base gas would be Argon, I suppose. The ammonia value in your picture is kind of confusing: it looks like you set a value of 90sccm, but no flux is displayed. That could indicate something about your MFC is odd. If it lets in random amounts of ammonia, a colour change to a nitrogen plasma isn't that surprising. Maybe check if that MFC is working properly. If you actually want to work with the ammonia, there is no problem about the plasma being blue.

The heating energy is shared, distributed to the nanoparticles, will be more energy distribution to NPs when the particles are metallic/efficient energy absorber/heat conductor.

THANK YOU I APPRECIATE

Dear Naime,

I suggest that you read the following paper:

Please let me know if you are unable to download it.

Kind regards,

Bahram

The nanostructures may scatter light if their optical size is comparable to the wavelength of light, if that's what you mean.

Dear Dr.

Yes, this is a work of modern methods. For delicious reasons, adding nanoparticles has many advantages. It has the ability to improve the performance and emissions in the engine as well as improving the thermal behavior of the engine. Adding nanoparticles to improve Oil by adding these materials to the lubricant oils. There are many advantages.

Best Regards

Hey Folks,

The attached presentation gives a good overview of both - Trassati & Dunn approach to distinguish the capacitive & diffusion current contributions. Hope this helps.

A biphasic mixture containing cyclohexane/water can be tried, in which the oleylamine mediated synthesis will be in cyclohexane and water mediated synthesized material will slowly interact over time to form the nanoheterostructure.

Hameem Habib You need to have a centrifuge machine. The machine which I had access to, can go up to 12000 RPMs. However, I centrifuged my material at 8000 RPMs. Something over 3000 RPMs can also work (with problems). But, I recommend 8000 to 10000 RPMs. Steps are as below:

1) Arrange centrifuge tubes.

2) Fill centrifuge tubes with your GO liquid mixture upto two-third. For example, if your centrifuge tubes have a capacity of 10 ml. fill them upto 6ml. All tubes must be filled with the same volume of mixture.

3) Now put centrifuge tubes in the centrifuge machine. Remember to place them in such a way that there is gap of one slot between any two tubes. Which means if machine has 6 slots for tubes, only three must be occupied by the tubes. This is to maintain equilibrium of load for the wheel when it spins.

4) Centrifuge the tubes for 15 minutes at 8000 RPMs.

5) Take out the tubes. You'll see brownish substance sticked at the bottom of the tube.

5) Take out the tubes. You'll see brownish substance stuck at the bottom of the tube.

6) drain the liquid at the top of the substance. Don't worry, substance will not fall off.

7) Now add remaining GO mixture in tubes and centrifuge again with same RPMs and time.

8) Repeat this process until all of your GO liquid is finished.

9) Now add De-Ionized (DI) water in the tubes. And remember to fill the tubes upto two-third.

10) Now shake all the tubes by hand (closing them with their caps) so that the GO substance settled at bottom gets mixed with the water thoroughly to form a mixture.

11) Again place tubes in the machine (remember to place them with the same gap) and centrifuge them.

12) After centrifuging drain the liquid at the top of the substance.

** This step will reduce the Ph of the mixture by reducing the HCL present in it**

13) Repeat step 12 until you achieve a neutral Ph (Ph of 8 would also work but please do some hardwork to achieve 7, I know it would require a lot of labour).

14) You can check the Ph of the liquid in the tube before draining it through a Ph paper or with the help of a Ph meter.

15) After a neutral Ph is achieved, use something clean to take out the GO from centrifuge tubes carefully.

Hope it helps. If you

Thanks for the comments. We often use ABCDE to highlight A means AI, B means Big Data, C means Cloud or Cyber, D means Domain Know how, E means Evidence. The value of AI, Big Data and Cloud is to convert Domain Know How to Evidence.

Yes, we have synthesized the SnO2 nanoparticles by chemical co-precipitation method. we have made the FL life time measurement to study effect solvents and calcination temperature on life time of carriers of synthesized sample. Refer our article "Strctural and Optical properties of Zirconium Oxide nanopaticles : effect of calcination temperature " which we have published recently in Nano Express. We will publish articles on life measurement on SnO2 nanoparticles soon.

Best of luck.

Sridhar Vadahanambi thanks you for this explanation.

as you said that the peaks are week, are they sill well distinguishable (should I even bother to Do Raman for "carbon dots").

If yes, then which Raman source (wave length) will give better peaks.

(I have access for 532 and 633nm )

Reminds me of: 'In theory, theory and practice agree. In practice they do not'

I would always believe one well-conducted experiment over one paper with more Greek letters than an Athens post-office.....

Hello Khac An Dao!

We have observed that the formation of ramifications, attached spheres and other imperfections could be promoted by the excess of reagent mass at high temperatures and preassures. It could be overcome changing mass and/or temperature and/or gas flux,

Greetings from Brazil!

please refer to this article

Preparation and thermal properties of stearic acid/titanium dioxide composites as shape-stabilized phase change materials for building thermal energy storage

pH play important role in the size of nanoparticles.  At high pH reduction rate is high. At low pH (below 5) instead of reduction oxidation will occur.  At very high pH (above 9, 10) reduction rate will be too much high resulting an aggregation of your nanoparticles.  So that is why pH 8 is desirable in order to synthesized smaller size nanoparticles

pH play important role in the size of nanoparticles.  At high pH reduction rate is high. At low pH (below 5) instead of reduction oxidation will occur.  At very high pH (above 9, 10) reduction rate will be too much high resulting an aggregation of your nanoparticles.  So that is why pH 8 is desirable in order to synthesized smaller size nanoparticles

You can use fresh aqueous extract of your plant.

Follow the below link

In fact your question is a bit confusing. Generally if you consider pure semiconductor in ideal situation, where [e^-]=[h⁺], then you are right it is confusing to know if it is n-type or p-type. But as we know, there exist NO ideal case, so at some stage [e^-]>[h⁺] OR [e^-]<[h⁺], then you might get n-type or p-type. This happens naturally due to the fact that our raw-material used for fabrication is not 100% pure and even small amount of impurity may change the neutrality condition to n- or p-type semiconducting behavior. For example, if we consider TiO2, then it might also show p-type behavior at some stage based on measurement conditions.

See the new published paper in SNB: https://authors.elsevier.com/a/1XTnA3IQMPAqJy

Article Cost-effective fabrication of polycrystalline TiO 2 with tun...

Dear Anjan,

Welcome,

Thermal co-evaporation of the dopant atoms is an a thermodynamic equilibrium process which means that the atoms are built on their equilibrium positions in the lattice. No post annealing is required after the deposition. However, the control ability of the doping concentration is crude and difficult.

The ion implantation is a very precise doping method with very controlled dosing of the dopants. However it is a dynamic doping process leading to damage after implantation requiring post annealing to recover the crystallinty of the material. One can also get a specific doping profile even for thin films which may not achievable at all by the gas phase doping.

Best wishes

This is a very good question.

In my opinion, the whole process "of conducting research, publishing it, and citing" is moving towards being more politicized. They may call it globalization but, apparently, this is a sort of colonization in which research endeavor in certain areas cannot progress unless it follows the lead of specific groups in other "far" countries. This way, the "masters" can be sure that they stay at the top while the others lag behind.

The story is much longer with many details... a good follow-up is required for writing a "review" or a "book" on this subject & the researcher can support it with statistics & figures.

Dispergation of powder after deep cooling.

Aren't they harmful for turbines and pumps?

Don't they cause defects like corrosion?

Please have a look of the attached files.

Dear Rassoul,

There are relatively few organic solvents that will freeze dry well - DiMethyl Acetamide is not one of them! It may be used for inks, but not freeze drying. Things like tert butanol, water, 1,4-dioxane, cyclohexane freeze dry well. DMSO can be used, but the risk here is having a suitable system for working with agressive organic solvents is the challenge (this is also true for DMAc.) as most dryers are made for water ...

To disperse the carbon black you will need a whetting agent in there, and you need to generate some viscosity in the mix to help it disperse well using a high sheer mixer. It is unlikely from my ancient knowledge of whetting agents (I'm not up to date) that these will not evaporate but will remain behind in the carbon black. Typically carbon black is dispersed into oils, not things that freeze dry well.

Do you really need to freeze dry? Is this the correct process?

Kind regards

Rob

a lot of the above will depend heavily what industry you look at as there are basically unlimited application examples, and no single source can cover metallurgy, semiconductor industry, building industry, medicine, pharmaceuticals etc.

I agree with Fiona Smail to explain the precautions but i want to explain some health problems.

Nano-material can be inhaled, swallowed, absorbed through skin, injected during medical procedures, may enter the bloodstream from the lungs and translocate to other organs, including the brain. Many metal and metal oxide NP’s have shown genotoxic or carcinogenic effects, systemic cadiovascular effects, detrimental effects on the cells with which they come into contact to DNA breakage and oxidation, mutations, reduced cell viability, warped morphology and decreased proliferation. Studies using primary or cultured human skin cells have shown that carbon nanotubes can enter cells and cause release of pro-inflammatory cytokines, granulomas, and pulmonary fibrosis, oxidative stress, and decreased viability. Engineered radioactive nanoparticles have applications in medical diagnostics, medical imaging, toxicokinetics, and environmental health, and are being investigated for applications in nuclear medicine produced many health problems . Titanium dioxide (TiO2) dust is considered a lung tumor risk.

I find a photo-link which explain the diseases associated to nano-material exposure.

Helpful Article

Dear Sir, there are several type that showed good heat transfer enhancement and for instance, SWCNT or MWCNT have superior thermal conductivity greater than oxide metal or ceramic, new researcher proved that Aluminum Nitride ALN is one of the promise type of ceramic family. in addition, it has special properties such as high thermal conductivity, high electrical resistance, corrosion and erosion resistance and because of these properties it is used in various engineering application. Regards

iCAN (Institute Collection & Analysis of Nanobody) has been created to expand and accelerate nanobody studies. Nanobody has family-specific sequence composition which can be mined to discover and design novel nanobody sequence.

iCAN contains information on the collected 2391 unique nanobodies. The collection of the database covers all publically available nanobodies that we could obtain from all sources including academic publications and industry patents as well as that generated in our lab. To our knowledge, it is the first public database of nanobody. Information related to sequence, protein definition, accession number, activity, target antigen, patent description and link to databases like PDB, PubMed and other related databases are provided for the benefit of users. The database not only collects the nanobody information, but also provides tools for sequence alignment and key words-based search.

Comprehensive documentation of the database can be obtained from the Help page.

So, have you carried out a Stokes' Law calculation?.......

I guess that you will not need a large amount of particles. It might be possible that still DISPERSED particles are which the supernatant after sedimentation (uv vis is a good method to measur the bandgab if the ethanol to not contain methylethylketone).

You know that the particles are modified with acetic acid? (IR can be use the monitor the modification)

Modification with levulinic acid  can lead to transparent dispersions in ethanol up to a around 5 wt%. Modification with fatty acid allows a phase transfer to toluene (also transparent, in this case a index matching might be possible) if you use the synthesis with in the publication.

Without water a charge stabilisation is hardly possible. Precipitation in water in general leads not to ZnO without thermal treatment of the powder.

Hi there, 

Simply follow the attached file as answer for your question.

Regards,

Yes Melody,

You can go for the cross sectional FESEM which clears how much is the coverage.

Or you can go with the DECTEK method.

And if you want to see the nano patterning of the carbon island which then create the improper coating or for the proper coating you can go for the AFM.

It is depending on the stability your dispersed particles in terms of viscosity and sensitivity of your solvent of interest.

You have filtered off all your material as all of it is aggregated > 220 nm.  See:

Nov 11th, 2008. Dispersion and nanotechnology  http://tinyurl.com/hpywsge

November 3rd, 2015 Adhesion and cohesion  http://tinyurl.com/zwb2wlh

I think your sample was not well dried.You can try  with washing with ethanol using centrifuge and make suspension in the ethanol. if Still bubbling persist,you can go through the paper referred by Mr. Jinming Guo,due to some core-shell interaction.

Also I - once you separate the conductivity due to micelles, by comparison with the theoretical Einstein-Stokes conductivity you'll get (quite inaccurately) size, number of micelles, and aggregation number.

    I assume you mean synthesis of metal nanoparticles via green reduction of metal oxide.  I think the concentration of reducing agent , reduction time and reduction method  are a major factors that control  reduction of metal oxide into metal nanoparticles.

Hi Mahmoud

We have used this product (Amicon Ultra-15 Centrifugal Filter Units from EMD Millipore) to separate ZnO agglomerates from dispersion with good success. After separation, we normally analyze the supernatent with UVVis to confirm the absence of the band edge peak on the spectra. Good luck!

Dear Khayri Al Zalit,

 How will you separate the activated carbon from the quantum dots?

Regards.

I suppose your iron oxide nanoparticles are suspended in a liquid host, and you are correctly trying to get info with the easiest technique, that is UV-Vis spectroscopy.

II am sure there is a vast literature available on the net, but you can get a first idea from the following link:

My research is based on the thermal conductivity measurement which I am able to perform as well.

We can liaise via e-mail: kamil.oster@manchester.ac.uk

Feel free to contact me

Kamil

I also agree with Titus. But the sedimentation depends on the method of synthesis also. If the surface of the nanoparticles are capped with hydrophilic substances, they will stay without sedimentation for long time. If they are uncapped even nanos will settle soon. In my experience the uncapped ZnO nanoparticles with average particle size of 60 nm will settle within  an hour if suspended in water.  UV visible spectroscopy is the simplest instrument available for nanoparticle characterization. Also, you can select based on your application, for example best dye degradation efficiency, best antibacterial property etc.

Sir,

In recommendation to Hisay Sir, the Pelletizer can be used to make pellets of powdered sample and then contact angle measurement would be easy. 

 Hello Rodrigo Amaral Coutinho Bartolomeu

Thank you so much for your valuable information.

Its really very helpful. 

Dear Natalia,

I published a paper concerning iron complexes "Advanced Materials 1995, 7, 173"

and if you are inrested I could try to prepare a PPI dendrimer derived from schiff bases using the same procedure.

Best whises

Mercedes

Hi Vijay

Great question. The shape evolution of Au nanocrystals from Au seeds is controlled by the relative growth rates of different Au facets as the nanocrystal gets larger. The growth of particular Au faces can be suppressed by adsorption of ions (e.g. halides such as F-, Cl-, Br- or I-) or organic macromolecules and surfactants such as CTAB, oleic acid, thiols or citrate. In your case, you are using a leaf extract in the synthesis of your Au  nanparticles. The leaf extract will contain a wide range of macromolecules with different reducing powers and adsorption characteristics, as well as simple ions, thereby leading to a broad distribution of Au nanoparticle shapes and sizes.

Attached are a couple of really nice papers to help you further

A Bioinspired Approach for Shaping Au Nanostructures: The Role of Biomolecule Structures in Shape Evolution       Chem. Eur. J. 2013, 19, 8220 – 8226

Defining Rules for the Shape Evolution of Gold Nanoparticles    J. Am. Chem. Soc. 2012, 134, 14542−14554

Best of luck for your future research

Geoff

Dear Anupam Thakur, 

Thank you.,

I am new to RF and MBE methods. Can you able to some papers links if you have it.

Pretty simple: by HRTEM, you 'see' the structure of your object which, in your case, is at least partly crystalline. In fact, what you really see, as Erico rightly pointed out, is the result of interference from your electron beam and crystal structure (any good textbook on HRTEM will explain that). So you're visualizing the crystal in real space (the object space), i.e. you 'see' the electron density distribution which is stronger at the atomic position. From this, you can directly measure lattice spacings etc. if you are in the right orientation with respect to the electron beam.

If you take the FFT^2 (i.e. you loose the phase but keep the modulus of the FFT) of your HRTEM image, what you basically get is the frequency distribution of the intensity of your object, i.e. a pattern looking like the XRD one (in reciprocal/Fourier space). That is because XRD is (by theory) the square of the 3D Fourier transform of your electron density (see any introductory textbook of XRD).

So remember, the FFT(HRTEM image)^2 = XRD image.

Now, SAED means selected area electron diffraction. What you do there, is that you image the electron diffraction of your object (by imaging the Fourier plane) and then select a specific diffraction peak which is imaged for each scan point. In this way, only the scan position of your object which is in the correct orientation will give you some intensity.

So all of those provide you complementary information, you can't really say that one makes more sense than the other. The only 'detail' you should remember, is that in HRTEM, you're only visualizing a (very, very, very) small portion of your sample (in the 100 nm range), while the beam size in lab source XRD is huge (in the mm range). If your sample is homogeneous, both would give the same information (assuming you have a fully crystalline sample). If your sample is heterogeneous, then you are getting a statistical average by XRD. So for practical reasons, you mayt want to use one or the other.

If you want to increase the yield of silver nano particles by biological method ,you will used plants that containing high amount of antioxidant agents .Attached article explain this

We are on the same page. I ran out of red mud that had been processed so I used some that has all its elements I used some to make ceramics. Unfortunately I don't have a thermostat for my kiln. The resort was it melted. In a further twist I was looking for magnets to see if I get the iron out of red mud and dropped the magnet and it fell on the melted remains and it stuck. 

I have since today infant ground the remains and there is lots of magnetic material I am going to get it tested for quality. I think it is suitable for pig iron,  sponge iron HBI or DRI  Thanks for your input.

You can use other reduction material instead Ammonia, also the there are anther parameters play as main roles to prepare nano particles, such as time of stirrer, temperature, and PH level. 

ATR FTIR is possible to use for liquid samples. It is fast and cheap technique. For good results the concentration of sample in liquid should be high enough. XRD can be used for liquid samples but not all devices allow it (I suppose this will be complicated for yours samples). For TEM sample preparation (including liquid) you can read chapter (see link below). Additionaly, AFM can be used for liquid samples too. Do you really need your samples in liquid? What property you want to study. For liquid samples some other techniques can be used (e.g. already mentioned AFM or DLS).

Ma'am,

If you have particles with different sized of same metal then you will get single broadened peak.

Besides a dispersion is always thermodynamically unstable there are at least 2 reason why you will not achieve. If you start with a powder your graphene particles will be highly aggregated. Opposite to what one might expect graphene surface is not dominantly hydrophobic. Therefore isoparaffins are not god dispersants. NMP, DMF are much more suitable. You may try to disperse it first in similar solvents and then blend with isoparaffins.

Dear Muhammad Triyogo Adiwibowo,

There is no well defined excitonic peak for ZnO nanoparticles; it varies because of the presence of various factors as mentioned in above answer. According to literature, their UV-Vis spectroscopic peak generally lies between 350 to 390 nm. If I am not wrong, you are getting peak at 420 nm, which depict the possibility to further reduce the size of your sample (ZnO nanoparticles). You can check this using TEM or you can calculate the particle size through UV-Vis spectroscopy itself. I am providing the link and paper to know more about the optical properties of ZnO and how to calculate the particle size.

Hopefully, It may solve your query.

Good Luck!

What are the thiols you want to load? If they are charged yoy can use them to stabilize the particles. You can stabilize the particles with citrate or the surfactant.

You cannot produce particles this small by a top-down process (e.g. sonication). You need a bottom up process.  Depending on your precursors, then the concentrations (and temperature) of the reducing agent and metal salt can be used to control the final particle size with lower concentrations of the metal salt tending to favor smaller sizes (as the collision frequency that causes aggregation, is reduced).  The materials must be kept in colloidal suspension to preserve the nano size.

there are several commercial products of narrowly distributed silica particles in water, e.g. Köstrosol, Lutensol. Colloidal stability in demineralized water is not a problem, even at isoelectric point around pH 2. At higher pH when negatively charged electrolyte addition causes agglomeration. Transfer to deionized water should not be a problem.

I agree with Titus, but I imagine inks are coloured!

Dear Yen-Ching,

1.I believe your Iron oxide nanoparticles are at their isoelectric point under this condition. At isoelectric point, the iron oxide nanoparticles having *ZERO* surface charge. So, there will be no electrostatic repulsion to prevent the particles from re-agglomerate. Note that agglomeration of iron oxide nanoparticles is favorable due to van der Waals and magnetic dipole-dipole attraction. 

2. My suggestion is, sonicate the particles for 15 minutes, adjust pH of the suspension to pH 3- pH 4. Then, sonicate again the particles for another 15 minutes and you will get a much stable suspension. At pH 3- pH 4, the particles gained net positive charge and thus develop high electrostatic repulsion among themselves.

3. Nevertheless, based on my experience, most commercial nanopowder unable to be redispersed back into their primary particle size. This phenomenon mostly due to the presence of sintered aggregates in the particles which formed during the drying process.

4. Hence, even you manage to disperse the powder into suspension form, the particles would have appeared as polydisperse agglomerates. I expect the presence of polydisperse agglomerates will, later on, affect the final size of your TEOS-coated particles.

5. Thus, I strongly suggest you begin with own made iron oxide nanoparticle suspension. There are numerous methods available in literature talking on the synthesis of stable yet monodisperse iron oxide nanoparticles.  

Best Regards

Hello Thripuranthaka M Nagaleekar

please check the attachments which are given below

Thank you Ali for your recommendation.

I will try this.

Thank you very much for your clarification and reply sir

Dear Yikai Xu

Thank you for your useful ideas. You always help me when I have a problem in my paper. It's appreciable.

Thanks

Hi Khalil

Have a nice time and good day , peace be up on you.

Sonication is a  successful  synthetic method  that   assists preparation of metal oxides.  The ultrasonic irradiation enhances the hydrolysis rate, and ultrasound waves pass through the solution  can induce unusual morphological changes in metal oxides. You will find many related  papers and articles .I'm not sure what you mean by large volume.

Regards

I suggest you to use CCD because it has better results in adsorption researches.

If your user conditions like pH, Time and... are same for all adsorbents, you can use all of your adsorbents as a factor in CCD.

for this you most set the categoric factors to 1. and set the numeric factors as many as your user conditions (pH, Time and...) is.

and in next page you most set the categoric factors level (number of your adsorbents)