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As mentioned in the figure, we want to separate oil from water or water from oil through a graphene oxide sponge based on porosity/surface functionality.
The pore size of the graphene oxide sponge is so small that oil is not allowed to pass through it and only water will pass when the surface functionality of the graphene oxide sponge is oxygenated. Same way, water is not allowed to pass through it and only oil will pass when the surface functionality of the graphene oxide sponge is fluoridated.
This is my approach for oil and water separation, I don't know whether is this correct or not?
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Thank you for response Federico Svarc
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I would like to functionalize an ITO (indium tin oxide) substrate with a SAM (self-assembled monolayer), let's say with MPA (3-mercaptopropionic acid). The first step is obviously to properly clean the ITO in basic medium to activate the surface (then rinse with water and isopropanol). Then, the ITO is simply immersed in an aqueous MPA solution over night. [1]
This procedure seems very straightforward, but there are different protocols of varying complexity (different solvent, addition of acid, different concentration, ...). After following the protocol, I have no way of knowing whether the surface functionalization was successful or not. What kind if measurement can I perform to validate my approach? Ideally, I would like to come up with a number such as "The surface coverage of MPA is X mol/cm2." or "X % of the surface is covered with MPA." Is there a method to quantitatively describe my result?
[1] Lee et al. Langmuir 2003, 19, 10, 4338-4343
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Damn, Matze I saw this thread rn. How funny it is that I am actually measured surface coverage using XPS of an acid on ITO. The article will be online in a couple of months...
There's another method: it's from electrochemistry actually. So you gotta run a CV of your SAM and calculate the total electrochemical capacitance by integrating the CV curve... Then you could actually calculate surface coverage actually...
In general the electrochemical capacitance is related to molecular packing density by the equation:
Density = Q/nFA (Q is the electrochemical charge which can be calculated from total current and scan rate), F is Faraday const. A is the electrochemical surface area exposed to the solvent.
Just use the SAM on ITO. Run the blank test on ITO and on this SAM and calculate. Please take note that blank ITO shall contain lots of In(OH)3 and oxyhydroxides InOOH type species ....which can't be removed fully even with sputtering...so the electrochemical area of the blank doesn't correspond to 'nothing on surface'. Your sample response will be representative of your SAM density though! Usually upon SAM formation these hydroxides/impurities leach out quite substantially (if not all).
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Dear all,
I've managed to functionalise my multiwalled carbon nanotubes using H2SO4:HNO3 (3:1) and have proceeded to the washing step via centrifugation and decanting. However, I am still unable to attain a pH of 6 to 7 as recommended even after 8 washes with ultrapure water. I saw some mentions regarding using a strong base like NaOH but I was wondering if it would affect my already functionalised MWCNTs. Aside from that, I couldn't find the explanation behind this step. Does anyone know how to increase the pH of my functionalised MWCNTs and the importance of that step?
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Aleksandra Benko Dear Dr. Benko, thank you for your comment and suggestion. It helps to know that I am not alone in this. I was a little hesitant about utilising a base initially as I was unsure if it would affect the outcome. Dr. Xuhua Wang advised me against using a base in my chat with her as well.
On another note, I came across a suggestion to utilise a dialysis membrane in a similar question several years back. A researcher at my university has suggested that as well. I have since resorted to using that and although it requires quite a few membranes and water changes, it seems to do well in helping me attain the neutralise pH required. Thank you both for your time and explanation.
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How to linearize any of these surface functions (separately) near the origin?
I have attached the statement of the question, both as a screenshot, and as well as a PDF, for your perusal. Thank you.
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It seems the linearization is accomplished by replacing x1, for x1^2. And separately by replacing x2, for x2^2 & x2^4.
In this way, the surface function is linearized about the origin (0,0), it means we can find f1(x1,x2)=a*x1+b*x2, whilst a and b are calculable in terms of the algebraic parameters, k and c.
But my question transforms to another level. How, we can find a compact algebraic expression for f1(x1,x2), and f2(x1,x2), close enough to the origin. This algebraic expression, need NOT be necessarily linear (it could be a nonlinear function).
Question synopsis:
1--How to find another compact analytical expression equivalent to f1(x1,x2), f2(x1,x2)? (with fair accuracy)
2-- Is it possible to find an approximation near the origin (0,0), for f1(x1,x2), f2(x1,x2), as a function of only one of the two variables (either x1, or x2)?
Regarding the second synopsis, I am to cite another ResearchGate question linked below:
However, the gist of the idea in this link is not clear to me.
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I am trying to etch surface of glass beads through NaOH for creating hydrophobic surface. Although the material is getting etched, it's not hydrophobic or positively charged. Also, the NaOH based etching method is not much predictable either. Are there any methods for creating hydrophobicity and a positive charge condition on glass beads?
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You can create a hydrophobic surface on glass surfaces "microbeads" or most any silicate glass surface by application of a silane monolayer. Etching is not generally required - though an etch with NaOH does produce additional surface area for additional bonding of the silane. Examples of this include the application of (Rainex®) or Aquapel® hydrophobic coatings for windshields and other glasses. One only needs Si-OH bonds on the surface. I suggest you refer to a review article on "coupling agents" - The simplest type of material that wold provide a hydrophobic material would be, for instance,
3(R)Si(OH) R could be CH3
More complex systems can be found at https://en.wikipedia.org/wiki/Siloxane
Email me or message me through Researchgate if you need more info.
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I have synthesized carbon dots that exhibit fluorescent properties, that are further coated with PEG through EDC. I want to separate them through gel electrophoresis based on the number of PEG attachment. Is the gel electrophoresis for Carbondots any different than gel electrophoresis for nucleic acids ?
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Santosh K Tiwari Thank you for responding I'll look into these
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I would like to know if there is any software that can be used to generate molecular surfaces functionalized/decorated with other molecular groups. For example, I want to start with a given XYZ/MOL2 file for a pristine structure (i.e. a carbon nanotube) and them, generate several other structures with other fragment (i.e. organic group -OH) attached randomly to its surface.
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OK, so you just want s drawing with maybe a simple optimization? You can use most structure editors like Avogadro, Molden or others to draw and perform a simple force field optimization:
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Hi there, I am doing functionalization of a citrate based polymer with EDEA using EDC Chemistry with NHS and MES. Can someone help me find a protocol for using EDC on a gel scaffolds. Most of the protocol I can find is by dissolving their protein or nanoparticle in MES buffer before adding the EDC and NHS. My sample is a gel and not in particle or in powder form and I am having trouble on how much and of what concentration of these reagents can I use to soak my gel and later on conjugating my amino. Hope someone who’s doing related research can help me with this one. Thanks
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Hi!
We are trying to use surface functioned microbead for protein conjugation. One major way is to use NHS functioned-bead. The manufactor also recommend the epoxy functioned bead. Both functionalisation can directly immobolise protein covalently. (aren't they?) Which conjugation reaction is more efficient?
Thanks!
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It depends on your target protein. NHS will attach the protein via amine groups ( amino acid Lysine in the protein). This is a very efficient and targeted reaction and lysine itself offer a spacer between the microbead surface and the protein. Epoxy groups are usually used to link with hydroxyl groups on the protein (amino acid Tyrosine) though it can also be used to link thiol, and amino groups on the protein. So, the choice depends on which amino acid in your protein you want to use and what impact it will have on subsequent use of the microbeads
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Hi Researcher,
I am using chemical surface functionalization of PDMS and Polyimide (PI) to achieve a irreversible bond. This method works really great and I have achieved irreversible bonding but I am not sure if this chemical process will cause any change in mechanical properties of PDMS?
In this process I have plasma treated PDMS and PI for 1 minutes and then immersed in 1% (v/v) solution of MPTMS in methanol and GPTMS in methanol for 1 h, respectively.
Thanks
Farooq
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Chemical bonding changes physico-chemical properties and the mechanical properties also change! It's important that can it be observed/measured at very small scale?
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I am carrying out surface functionalization of LDPE.
How do I use the FTIR spectra to quantitatively determine the functional groups on the surface?
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If you are trying to detect a surface functionality of a film with monomolecular layer equivalent, I doubt if you can see any surface functional groups using FTIR. Using a thin film. Using a thin (1 mm thick) Si ATR crystal, you might be able to detect one of the strongest absorbing groups, carbonyl. Using special samples, conditions and/or techniques, you might be able to study the surface of polyethylene. See the papers shown below. We used a PE fiber for the first paper, but you might be able to use a very fine PE compacted powder as well. Note that when you obtain the diffuse transmittance spectrum, you will not be able to see a spectrum in the same manner as in usual transmission technique. The spectrum would be at the bottom of the screen. You need to expand the spectrum in the y-axis. The second paper utilized a very special technique called surface electromagnetic FTIR spectroscopy and detected carbonyl groups in much less than a monolayer equivalence.
"Diffuse Transmittance Spectroscopy of Polymeric Fibers," A. Taboudoucht and H. Ishida, Appl. Spectrosc., 43, 1016 (1989).
"An FT-IR Study on Interfacial Interactions in Ethylene Copolymers/Aluminium Laminates in Relation to Adhesion Properties," L. Ulren, T. Hjertberg and H. Ishida, J. Adhesion, 31, 117 (1990).
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I have a spincoated thin film of P(VDF-TrFE). I'd like to attach a thicker, transparent film as a backing layer that would allow me to pull off the PVDF film without it crinkling. I have access to a variety of cleanroom tools and extensive experience in chemistry and surface functionalization.
What are some good candidate backing layers that will tolerate temperatures > 120 C? If functionalization or e-beam evaporation is needed, I prefer to do this to the backing layer, not to the PVDF. I'm currently looking at ways to functionalize PDMS, PET, and PI.
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Kapton (polyimide) is effectively the most widely used polymer if you want to use it as a substrate. However if you are looking for an interstitial layer that you can deposit and then peel of, Parylene may be better. It can be deposited by thermal evaporation, resists the temperatures associated with most classical microelectronic processes and will provide a very smooth surface if deposited on glass or Si wafer.
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I need to functionalize a glass surface with DNA (my method of functionalization is crosslinking amine terminated DNA to aminosilanized glass with gluteraldehyde). I then need to bond that functionalized slide to PDMS. 
Im afraid O2 plasma will destroy my DNA probes. Any papers on this?
Im going to try the following but i was wondering if anyone has any input on how well any of these alternate methods work/methods to enhance these:
-Glass + PDMS + weight ==> oven 80C (would a hot plate work?)
-Piranha treat PDMS
-Plasma treat just PDMS
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3696384/ this is kind of intense, is there a way to do this without the UV?
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Flexdym is a great alternative to PDMS, which does not require O2 plasma bonding.
The fabrication protocol is easy to use and only 2-15 minutes long, depending on your application. And because Flexdym is a thermoplastic, it can be recycled and re-molded. Check it out at https://eden-microfluidics.com/
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What are the main differences between Graphene Oxide and Expanded graphite, in terms of surface functionalities, conductivity, d-spacing and other features? Is the term expanded graphite synonymous to exfoliated graphite? Kindly help.
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Graphene oxide is manufactured typically by modified Hummers' method. There are a number of conditions but basically it uses oxidizing compounds to chemically oxidize graphite which is near perfect fused ring 2-dimensional sheet stacked up with many layers. Upon chemical oxidation, many defects (chemical functionalities) are inserted in these perfect lattice and weakens the interaction between individual sheets, which allows to separate each sheet. Some of those functionalities are internal epoxy group, phenolic group, and carboxylic acid groups. When you say "graphene" oxide, you imply a single sheet as graphene is a single sheet of the graphitic layers. One unique aspect of graphene oxide is the presence of chemically reactive functionalities on the basal plane in addition to the edge plane. This makes difference from typical silicate nanofillers which has available chemical functionalities (typically SiOH groups) only at the edge plane. Those that exist on the basal plane is embedded deep from the surface and cannot form covalent bonds with external chemicals, though it might weakly form hydrogen bonds. As a result of the insertion of chemical defects on graphene, graphene oxide's reduces electrical conductivity drastically from graphene, though the majority of the mechanical strength is maintained.
Expanded graphite is not a single layer. It is manufactured by inserting concentrated sulfuric acid into graphite and the sulfuric acid intercalated graphite is suddenly heated to a high temperature. This action will expand the d-spacing of the graphite and will be easy to further expand upon certain applications, such as a flame retardant additive. Since individual layers are still aggregated, the expanded graphite is not regarded as nano fillers nor it has the ability to reinforce polymer matrix like graphene nano filler since the aspect ratio of the filler is so small. Since concentrated sulfuric acid is used (and sometimes with nitric acid mixed), it is natural to expect the chemical reaction with the graphite layer by inserting sulfonate groups and carboxylic acid groups in a similar manner as the chemical surface treatment of traditional carbon fibers by those chemicals (though commercially, carbon fibers are oxidized by electrochemical means). Again, by inserting these chemical groups, the electrical conductivity reduces significantly from the pure graphite.
Thus, the similarity of graphene oxide and expanded graphite is that both have chemical functional groups inserted into the graphitic lattice with the corresponding chemical groups used to treat. The main difference is that graphene oxide is typically a single or few layers of oxidized graphene (nano fillers) whereas expanded graphite is a stack of so many layers and is still a usual filler size (many micrometers or even millimeters in both thickness and length. It is a usual filler size). Discussion of d-spacing is meaningless for graphene oxide (ideal graphene oxide has only single layer and thus usual layer-to-layer distance does not exist. If you are interested in the thickness of the layer, it is close to 1 nm). On the other hand, the expanded graphite has so much breadth in d-spacing and again it is almost meaningless to discuss about it.
The term exfoliated graphite is seldom used, but the meaning of this corresponds to graphene. When you exfoliate graphite, each layer is so distributed without the position alignment (random) and each single layer is distributed without any preferred position. This is the definition of graphene.
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Dear colleagues
  • Is there a simple protocol for short-term coating or fixation (just some hours) of surfaces with silver nanoparticles (Heating? Irradiation ? pH ?) ? I wonder if there is a way that could work the same for many types of surfaces (metallic alloys, polycarbonates...), also I should not have any other organic or major inorganic residue after the coating.
  • My goal is to obtain an AgNP coated surface for short biological experiments. The best is that I can use pre-existing nanoparticles radher than a protocol involving on-surface synthesis.
Thank you for your valuable advice.
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It's very easy to fix a silver precursor (ammoniacal silver nitrate is often used) to a substrate and reduce in situ. Supported metal/metal alloy catalysts are a good example. Here the size and loading of the metal can be controlled relatively easily. You could also try buying in one of the silver witchcraft recipes and absorbing onto a surface but here the concentration is likely to be very low (ppm) and not controllable. Further, making your own is probably much cheaper and you'll learn more. For an overview take a look at this webinar (registration needed):
Silver colloids and invisible ink
... and the even more general:
Metal colloids - their preparation, application and characterization
Be aware that the active bactericide is Ag+ and not Ag0. The surface of all 'silver' materials in air or water is always fully oxidized and it's the solubility of the nominal oxide that confers the properties.
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i did titration to determine functional groups on the surface of activated carbon, when the titration was done on Na2HC03 and NaOH by HCl, a big volume was necessary to reach equilibrium, and after doing calculations, final quantity of matter was greater than the quantity of matter calculated at the beginning. It seems ambiguous.
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Thank you for answering me Marcos
Best regards
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Formites, any disease transmitting surfaces, may be coated to prevent cross contamination of preventable communicable diseases. The effort is to find products that do not alter the surface functionality and to maximize the time between initial application and refresh coatings.
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Dear John,
The use of antibacterial and antimicrobial cleaning products – combined with the over-prescription of antibiotics – may produce strains of bacteria that are resistant to disinfectants and antibiotics.
The overuse of antibacterial cleaning products, including disinfectants in the home, may be producing strains of bacteria that are resistant to multiple antibiotics. Bacteria that are resistant to many antibiotics are known as multi-resistant organisms (MROs). These cleaning products are no more effective at preventing infection in the home than good personal and household hygiene using ordinary soap, warm water and plain detergent.
Most bacteria actually help humans. When you use antibacterial or antimicrobial cleaning products, good bacteria are also killed. This could be harmful if the ratio of good to bad bacteria is disturbed, and bad bacteria get the upper hand.
Solution:
The solution: permanent antimicrobial coating of surfaces. While most EPA and BPR-registered active ingredients for hard surfaces are non-toxic, their promised effects on odor-causing bacteria and mold growth (mold control) leave a lot to be desired. Antimicrobial surface coating is much helpful here. Ity may prevent contamination and subsequently disease as well.
Ashish
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Nanocellulose. PPE (Personal Protective Equipment). Lignin. Face Masks. Surface Functionalization. COVID-19. Protection
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Functionalized nanocrystalline cellulose with antiviral element or oxides can be used in fabrics and mask.
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Due to using probe sonicator for re-dispersing silica nanoparticles, I am getting black depositions at the bottom of the falcon tube. Can anyone suggest me any method to re-disperse silica nanoparticles?
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Bath sonicator and vortex are widely used for this purpose
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I am trying to functionalize PE films by UV treatment and using 5 % benzophenone as a photoinitiator. But I am not able to receive any bond shift even after a considerable exposure time. What could be the problem?
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You need a high or medium pressure mercury lamp and should exclude oxygen (either cover with glass or use N2). Also, not sure what you are trying to graft but acrylates work best. Benzophenone is a type II initiator (sensitizer) and works best with a co-initator such as an amine. Other initiators (Type I) such as Darocure 1173 may work better.
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I have successfully synthesized lanthanide up-conversion nanoparticle using hydrothermal method, they are hydrophilic in nature with positive surface charge as confirmed through DLS.
I want to make surface charge negative.
I know there are lot of articles about surface functionalization, but most of them are related to switching from hydrophobic to hydrophillic.
can anyone please share the relevant information about it?
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Zeta potential is not surface charge.
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I'm looking for a method to attach APBA to a SU-8 surface. Until now, I'm not very successful in the process.
The SU-8 is a 1um film deposited over a surface. I'm trying to immerse the substrate in 80mM of APBA in ethanol.
Can you give me an advice?
Kind regards.
PS: Chemical molecules and suppose reaction
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Hi Manuel.
Oxirane ring can reacts with alcohol via etherification reaction. But it needs catalyst such as tertiary amine (triethylamine and etc.). Also, it easily reacts with amines.
Relating to your synthesis , may be the ethanol (solvent) participate in oxirane ring openning reaction.
Also, higher temperature im more favorable.
Don't use solvent or If you need solvent, change it.
Good luck
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In recent years Graphene quantum dots with very high Luminescence (Quantum yield) are reported. These QDs are generally dispersed in DI water (some time organic solvents as well). PL of GQDs in 400-500 nm (absorption 300-400 nm ) is credited to Surface functional groups (-OH,-COOH,-NH2).
But is it even possible to retain these optical properties if we try to obtain there GQDs in powder form or if we want to coat them on some substrate?
If yes then how to do it?
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Rahul S. Tade thank you I will check these out
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Is it ok to keep it in air or does it need to be kept in certain solvent to preserve its thermo-responsiveness?
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Hi. I have been preparing PNIPAM polymer brush functionalized gold surfaces for quite a while now and noticed that even months after the preparation the thermo-responsive property is preserved, so my suggestion that storage in air is fine. However, before attempting some serious experiments with the PNIPAM functionalized surface, ensure that the material was hydrated before, so that the swelling/collapse property is re-established as it should.
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Could anyone suggest me the best capping agent for Silica. End goal is to have amines on the surface of silica nanoparticle after capping them. Have used APTES in the past.
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liquid ammonia
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Dear all,
I am using the Boehm Titration for quantifying the surface functionalities of my materials. In the procedure of Boehm Titration, it says that, NaOH neutralizes carboxyl, phenolic and lactonic; Na2CO3 neutralizes carboxyl and lactonic; and NaHCO3 neutralizes only carboxyl groups. Does anyone can please explain why the NaHCO3 neutralizes only carboxyl group? similarly, why Na2CO3 neutralizes carboxyl and lactonic groups? and so on....
Thanks.
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As you know, NaOH is stronger base than Na2CO3 and both are stronger than NaHCO3. If a base is strong it can neutralize all the acids even very weak acids like phenolic but the weak bases can not do so.
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we want to know the relationship between the type of functional groups on a particle surface and the magnitude and type (+ or -) of zeta potential. For example when carboxyl groups are on the surface versus the amin functional groups.
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Keep in mind that zeta potential is not a measure of the surface charge of the particle. It is a measure of the electrical potential some distance away from the surface. Adsorbed species (e.g., ions) shield the charge. In some situations it is even possible to have a zeta potential of opposite sign to that of the charge at the surface of the particle.
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As far as I know the PEG layer (or other functional group) can be formed in two ways on the surface of nanoparticles: mushroom or brush. Does this formation depend on whether the nanoparticle surface be flat or curved? in the other word, is the any relation between configuration of PEG layer and the shape of nanoparticle?
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Yes, in my opinion the shape and surface area affect grafting density which induce mushroom or brush formation. In addition, it also depends on the interaction with solvent, molecular weight of the PEG, and functional groups.
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hi
what could be the best way to characterize basalt fiber surface. I have coated Basalt fiber and from FTIR i did not get much information? Is there any other technique with more sensitivity for detection of surface functional groups?
thanks
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This article may be useful to develop alternative coating on basalt fibers
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Hi. I am using EDC-NHS chemistry to modify PLGA surfaces using proteins. Is there a certain reaction time for the amine reactive NHS ester after which it becomes inactive (or less reactive) and does not aid in further protein binding to the surface? 
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I agree with Omar.
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How does the hydrophilicity/hydrophobicity of a support (like carbons) affect the particle size of the metal particle ?
Does the surface functionalities on the carbon surface any effect on the size of the particle formed?
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The homogeneous formation of the nucleus of a new phase is observed when there are no surfaces in the system on which the formation and growth of the nuclei of a new phase occurs at a sufficient rate.
The heterogeneous formation of the nucleus of a new phase is observed with the introduction of the seed of the substance of the new phase itself or of a substance close to it in structure and properties.
You give an example of a heterogeneous formation of a new phase. Therefore, the surface of the old phase will affect the formation of a new phase. Particles of metals are hydrophilic. Therefore, the hydrophilic old phase will affect their formation. The hydrophobic phase will affect much less. Of course, one cannot exclude another interplay of the chemical structure of both phases.
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Good afternoon! I am currently working with PVDF membranes (pristine PVDF and PVDF surface functionalized with OH) (These membranes are not electrospun). I have attempted to tissue culture fibroblast cells onto the membranes to test for their adherence and have used the standard DMEM media (3T3 media) during this procedure. The media was changed every two days for 10 days, however it was noticed that the media would turn purple everytime (upon measuring its pH, the media has become more basic). The same observation has been noted even immediately post-sterilization when the membranes were soaked in the media for 30 minutes prior to starting the subculture process. Why has this occurred?
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The tissue culture media contains Phenol red , which turns yellow in acidic conditions and purple in basic conditions.
The only explanation is that your PVDF membranes are releasing a basic chemical into the media. Your membranes will need further treatment to remove this chemical tha tmust be present following functionalization.
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I'm working on a small project where I'm trying to covalently bond nanomaterial to polyethylene. For reasons to long to describe, there are -NH2 surface functionalities on the nanomaterial that I would like to use to bond to the polymer chain (polyethylene) and I've come to a bit of a standstill when trying to find a way to do so. Any ideas?
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Thank you for the help, it seems that using pre-modified PE is the only possible solution then!
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Hi, I want to probe single particle rotation at water-glass interface. Any suggestions on surface functionalization techniques on glass so the particles are still rotating in-plane but somehow stuck to the glass?
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We are looking for a procedure to surface treat commercially available Er2O3 nanoparticles that do not have any surface coating to start with. The aim of the treatment is to cap Er2O3 nanoparticles with ligand molecules of short moiety spacing like MPA or MHA. There has been a large body of literature on how such surface functionality should be conducted for semiconducting nanoparticles like CdSe, ZnS and ZnO etc., but we haven’t been able to find a single paper on surface functionality of Er2O3 nanoparticles.
Can anyone tell if a procedure starting with dissolving Er2O3 nanoparticles in toluene, followed by adding MPA or MHA in the solvent, could lead to the passivation of Er2O3 nanoparticle surfaces by the thiol group (SH) of ω-mercaptocarboxylic acids, whereas the carboxyl group (COOH) of MPA or MHA may bind to the metal ion at a metal oxide surface? Thanks a lot for your attention.
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Thank you so much - Allan! Your comments are very helpful to us.
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We are optimizing the assay parameters for our TSH immunoassay. We had been using a 7.4 pH PBS buffer for antibody coating so far, but now want to evaluate if changing the pH of the coating buffer would enhance the binding of the TSH capture monoclonal antibody to the surface.
The surface is PMMA surface, modified with PEI to give amine-PMMA, further modified to give Glutaraldehyde as functional group on the surface.
Similarly, would changing the buffer for blocking buffer (currently using 1% BSA in PBS), improve binding?
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Thanks a lot for your detailed answer
Our method is same as here-
As suggested by you we are exploring different blocking buffers, starting with the ones used with western blotting.
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Hi everyone, I'm trying to do epifluorescence imaging of a FITC-SH functionalized gold surface. The area is flat and of ca 200 um x 200 um. Currently I have been able to see only a dim light coming from this surface, barely distinguishable from the control (not functionlized gold) area. In addition, I am using a very long exposure time (20s) and high gain (x10) with a 20x-air objective, which seems a bit strange to me. Things didn't go much better by using a confocal microscope.
Could it be some quenching effect of the gold surface? Can the imaging in dry condition somehow affect the flourescence of the FITC? Thank you in advance for the help.
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The distance between chromophore and gold in this case is very small, therefore, quenching should be expected. But this is not the only reason which would explain that you do not observe much fluorescence here. In best case, there is kind of monolayer of dye molecules on the gold surface. The distance between dye molecules in (more or less dense) monolayer is small, so concentration quenching may be expected on the one side. On the other side, the total amount of dye in the observation volume (with a thickness of at least couple µm) might be too small to expect a bright fluorescence. In worst case, there is simply no surface functionalization - having just a thiol group is not enough to form a stable and densely packed layer. In any case, the dim light you are seeing might be just due to scattering, which increases with the surface roughness.
Are you following somewhere published procedure or trying your own? Having something like FITC-(CH2)n-SH (or, in general, any few nm thick sublayer between gold and dye) should greatly improve fluorescence.
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I want to use a Sonoplot Proto to functionalize a sensing area. For low viscosity liquids (1-2 cP) the humidity must be very high for it to work. I want to try coating with oxygen plasma to improve hydrophilicity. Does anyone have other suggestions ?
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You probably can improve it my spraying some ethanol on the surface prior to fictionalization. I usually dip it in ethanol bath for 5min then nitrogen blow dry my surface, it works for me. However, my application is different with what you are looking for...
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In polyelectrolyte (PE) assembly, PE solutions are often made at 1 mg/ml concentration however, solvent used varies. Some papers mention 0.5M NaCl solution pH 4.5, sodium acetate buffer pH 4.5, water, phosphate buffer saline pH 7.4 etc. pH should be in the range at which given polyelectrolyte remains in charged state. How one should decide which solvent/buffer viz. 0.5M NaCl or PBS or water (pH adjusted as per requirement) is ideal for his/her polyelectrolyte assembly experiment?
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Hi Anna,
Thank you very much for the reply and recommending reference articles. They have proved to be helpful in a great way.
I am following "Washless layer by layer assembly" protocol developed by Prof. Yuri Lvov and colleagues. I have two different HA (Mw.200 Kda an 1000 kda).1000 kda HA makes NLC suspension thick and viscous if its used for layer by layer assembly. With 200 kda HA at 1 mg per ml concentration in a buffer instead of 0.5 M NaCl, I have been able to achieve desired results and am engaged in further modifications.
I have a question/doubt
1. Can we achieve D+ mannose coating on nanocarriers using layer by layer assembly? Can it be coated as outermost layer, because I think as mannose is a carbohydrate molecule and have affinity for water, it may get eroded or can get dissolved when coated as outermost layer over the period of time.
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Hi everyone, 
I have a short question to ask if it is possible to surface functionalise the aluminum micron size particle(which has a thin layer of Aluminum oxide on top of it) with APTES? 
Thank you so much and I am looking forward to your kindly reply soon. 
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We performed this reaction for graphene oxide under dry conditions and resulted in a desired product.
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I am trying to functionalize silicon substrates with DNA. The idea is to use APTES to add amino groups on the native oxide layer and via a bifunctional linker, sulfo-SMCC, to link them to thiolated DNA.
I saw 2 publications doing so but with TEA buffer, don't understand why.
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TEA is a strong base in aqueous solution. Additionally to activation of existing silanols, it could activate splitting of siloxane surface groups by H2O to give more surface silanols.
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Hi dear all,
Recently, I am doing research using activated carbon (AC) cathode to reduce O2 for H2O2 generation. However, I found after saturated by reactive blue 19 (a dye), the performance of AC didn't decrease obviously, which confused me.
Therefore, I was wondering is it because the active sites for O2 reduction and adsorption are different?
Generally, the active sites include defects, surface functional groups, heteratom. Can I understand the difference from this aspects?
Thanks in advance!
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Along with the specific surface area, the nature of the surface is important for the catalytic activity of carbon. Some reactions may occur with the presence of oxygen complexes (alkylation, hydrolysis, esterification) on the surface, others in the presence of dissociating groups (H-B exchange, isomerization, hydrogenation) or surface active centers (dehydration). There is a direct correlation of the catalytic activity of oxidized coals with the amount and acidity of surface proton donor groups. With the presence of oxygen functional groups on the surface of carbon materials, as a rule of acid nature, not only catalytic, but adsorptive and oxidizing properties are associated. The type of functional groups and their acid strength depend on the type of oxidizer and the conditions of the oxidation process. Nitric acid, hydrogen peroxide, as well as permanganates and bichromates are most often used as oxidants.
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Hi,
I'm working on an electrochemical biosensor integrated into a microfluidic system. The working and counter electrodes are gold, and the reference electrode is Ag/AgCl.
I'm planning to either immobilize thiolized nucleic acids on the bare gold WE surface, or use 11-mercaptoundecanoic acid SAM method to functionalize the WE surface for EDC-NHS coupling to proteins.
Due to the way the microfluidic device is fabricated, I may need to immobilize the biorecognition probes within closed channels (post-bonding). I also want to functionalize only the WE, while keeping the CE/RE uncoated.
Can anyone guide me on how this can be done?
Thank you,
Afiq
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Hi Afiq,
You can make electrochemical desorption of 11-mercaptoundecanoic from the CE. The electrochemical desorption can be done by sweeping the potential between 0 to -1.4V in 0.1M KOH solution. You should optimize the potential window.
Good luck
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Spectral matching is the obviously required for efficient FRET. But for FRET between Quantum dots (donor) and dye (acceptor), what is the role of surface functionalization. For example if one is amine functionalized and other is carboxy functionalized or both are carboxy functionalized, what would be the possibility of FRET, acceptor emission enhancment and acceptor emission quenching?
Thanks for your answers.
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Hi Fahad, I think you should examine the fluorescence properties of individual surface bound fluorophores before doing FRET.
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I am studying the effect of extended ultrasonication on the synthesized graphene oxide nanosheets ( specially on the activity of surface oxy-functional groups ).
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Dear Abhijeet, As per my knowledge ultrasonication can reduce the size of GO sheets and during that time it may break the chemical bond between the graphene layer (-C=C- backbone) and the oxygen containing functional groups. But, complete removal of functional group may not be possible. Further, you have to keep in mind one thing that excessive ultrasonication will reduce the size drastically. So, the materials property will change a lot.
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I am looking for superparamagnetic nanoparticles with a polymer coating for our experiment. They can be in submicron size. They don't need to have surface functionalization as we have our own method to do that. If you know any supplier or your research group can provide this type of nanoparticles, please let me know. Thank you very much.
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I want to clean "Gold Coating Particle from the PDMS surface". Is it Is "Ultrasonic cleaning with Ethanol" ok to do this task? Please suggest a suitable process.
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If you need a very clean process you can use laser ablation by UV pulsed laser
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I have nitrogen and sulfur on the sheets.
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X-ray Photoelectron Spectroscopy is by far the best tool for this kind of job in my opinion.
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I am Functionalizatng the Silica Nanoparticles with Various Mono-Alkoxy Derivatives such as methoxydimethyloctylsilane, methoxytrimethylsilane using the process of ultrasonication. 
I want to know that how ultrasonication leads to the surface functionalization of silica nanoparticales with the chains of methoxydimethyloctylsilane or other Mono-Aloxy derivatives?
Only mono-Aloxy derivatives can be used for the surface functionalization in ultra sonic processing?
 
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You do not need ultrasonication for silanization reactions to occur. Perhaps you are only helping in nanoparticle dispersion and the created heating will only accelerate the condensation process.
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For the making of the super hydrophobic surface, we need contact angle greater than 150 degrees. For that which silane gives the best contact angle? how will NH2 affect the hydrophobic character IF a silane with NH2 is used? like amino propyl tri methoxy silane or 3 amino propyl tril methoxy silane 
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Well, hydrodroxymethyldisiloxane HMDSO is evergreen precursor for superhydrophobic layers deposition. Organosilicon nature of plasma deposited HMDSO guarantees the superhydrophobic nature. Then you can play with the roghbess of the coating and by increasin Ra you obtain higher WCA. The presense of amine group decrease the superhydrophobicity and WCA, because NH2 Is hydrophylic group. Look to some of my papers. APMS OR APTES  are not good precursors for superhydrophobic layers deposition. The addition of fluorine will increase WCA  for sure but I have concerns regarding the toxicity of such precursors.
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Carboxyl-anhydride and amine plasma coating of PCL nanofibers to improve their bioactivity
Free download via link below or please contact me.
The plasma modification of biodegradable nanofibers is of great interest for improvement of their biocompatibility. However, there are no systematic studies regarding the influence of plasma polymer deposition onto the surface of nanofibers to improve cell adhesion. In the present study, homogenous and reproducible modification of polycaprolactone (PCL) nanofibers by amine and carboxyl/anhydride groups was achieved. The concentration of amines NH2/C and C(O)O contribution were up to 2.9 and 14.1%, respectively. Regardless the plasma conditions, the deposition of amine and carboxyl-anhydride plasma coatings onto the PCL nanofibers sufficiently improved the cell adhesion and viability, as was evidenced by microscopy observations and ATP assay results. It should be emphasized that the deposition of negatively charged carboxyl-anhydride coatings resulted in slightly better cell adhesion compared to the positively charged amine plasma coatings, unlike the widespread opinion that COOH modification has less effect on myoblasts adhesion
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Thank you Anton for sharing your nice paper
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We use oxide nanoparticles for human cell studies. We functionalize nanoparticles with silane group and Alexa Fluor 488 dye. However, the signal of fluorescent dye is not enough to follow the nanoparticles in cells. 
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I have some thoughts. However I need to understand more first. What reference information do you have for the method you are using now? Has it been successful for someone else? How do you know that your loading of dye on the particle can be increased? What independent test have you done to confirm that you are not already at full coverage?
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I have observed in my study that post chemical treatment of a biomaterial, the intensity of the peaks (IR) has increased compared to untreated. The groups corresponding to the peaks are amines, carbonyl, carboxyl, and esters. If the chemicals used are sodium hydroxide, nitric acid or calcium chloride (independently)  what could have caused this increase in intensity? Does it involve any chemical reaction with the existing groups? If so what (to be exact)?
Consider the biomaterial to be a lignocellulosic material.
Any answers are welcome. I would be grateful if chemical reactions could be given to explain the reason involved.
Thank you.
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In general, with all else being equal, IR intensity is proportional to the number of absorbing species per unit volume. In a perfect case, an increase in IR absorbance means that you have increased the concentration of the species. The concerns are that samples must be normalized to exactly the same state. Any change in properties such as sample thickness, reflectivity, or bulk density will also affect IR intensity. A required first-order approach to compensate for this is to normalize the spectral intensity against an internal calibration standard and to perform other characterizations to complement the IR.
In summary, a simple answer is not possible from general principles.
My subsequent recommendation is to do a literature search for IR studies of comparable materials to what you have. Review how they address your questions. Someone with the requisite specific background may also chime in here to point you in the proper direction.
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Hi every one
The most known method for synthesis of silica beads is the "Stober method". what are the other methods to reach this goal?
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Yes, the stober process. Good luck
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i am trying to make oleic acid capped iron oxide nanoparticles. but there comes washing problems.
my method was
1. reaction mixture 10ml+ ethanol30ml mix
magnetic separation. decant supernatant.
2. add little ethyl acetate to remove remained 1-octadecene(reaction solvent). decant ethyl acetate.
3. dried over high vacuum for 1h.
4. tested dispersion ability in n-hexane, chloroform , and cyclohexane.
sometime they were dispersed well in nonpolar solvent, but somtimes they didnt be dispersed in nonpolar solvent.(Agglomerated)
is there any precaution when i wash nanoparticles? i check TEM image and found nanoparticles were well made. 
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Hi,
I am working with an alcohol solution saturated with LiOH and I need to make precipitate LiOH on the Silica surface, in particular I would get an uniform coating of the nanoparticles that I can not reach using just Silica nanoparticles without any functionalization.
So I think that the Silica nanoparticles functionalization could be helpful for my purpose, because I need to increase the affinity of the nucleating specie (Li+, OH-) toward the Silica nanoparticles surface.
The uniform coating can be obtained if I will be able to increase the nucleation points on the Silica surface instead of the growth of the few LiOH nuclei formed on the Silica surface; since the nucleation points on the Silica surface increase if the affinity between the LiOH and the surface is higher, I guess that by means of the silica nanopartices functionalization I could reach my purpose.
Could you suggest me some papers about the adsorption of Lithium ions and/or OH- on functionalized surfaces? or some paper which could be helpful for my purpose?
Thank you 
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You have to work in various temperature as an one of your parameters to find optimum conditions that gives you better participation
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Is someone (industry, research groups) interested on -COOH functionalized silica nanoparticles? I know that several commercial sources are available, but they seem to be expensive for just a few miligrams. Would they have demand or usefulness if they were cheaper? Is someone interested on them?
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Hi Miguel, -COOH surface functionalized nanoparticles are more useful that you think.
The  -COOH surface can be modified by  ethyl(dimethylaminopropyl) carbodiimide (EDC) and though that you can couple organic and inorganic compounds with primary amines. The possibilities are endless.
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i want to use the polyamic acid to conjugate ti antibodies using the EDC/ NHS coupling system.
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i think for this kind of attachments and bonding between functional groups we can use  coupling agents such as DCC/ DMAP or EDC/NHS in a controlled condition. as you know thiol groups have a good ability to gold and you should activate gold nano particles by a double functional molecule that one of them should be thiol for attach to gold surface and another can be OH,COOH or NH2 . anyway you should attach the polymer to activated gold nanoparticles.
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Hello everyone,
I would like to know if there are any publications or any method to calculate partial charges of C,O, and H in functionalized graphene. I have done some literature search but could not get any information. I am doing molecular dynamics simulation of functionalized graphene. We know that in graphene C is treated as chargeless sphere but what about C,O,H in functionalied graphene?
I would appreciate any help.
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Hi Arnab,
I know the charges of O and H from CLAYFF which are -0.95 and 0.425, respectively. However, when they are in combination with C, I suppose, the charge redistribution will occur and charge on C will no longer zero. Are you saying, I can calculate the charge of C using QEQ fix method in LAMMPS?
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I am working with a tribo geometry for food studies and wish to characterize the properties of the pdms surface.
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Confocal microscopy would be appropriate tool.
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The polymer with CH3O(CO) end group should coat the surface of MNPs, which are functionalized by NH2 group by preparation of amide band.
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Thanks for your guidance. Indeed, my sample is made up of  Fe3O4 nanoparticles, functionalized by 2-aminophosphonic acid and polymer is poly vinylcaprolactam with ester end group. I am doubtful about addition of base or acid to the solution of nanoparticles and polymer because I don't want the polymer to be hydrolyzed.
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I need to conjugate one of the alcohol group of PEG with the carbon in R-N=C=N-R.
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Use methoxy-PEG-OH, i am not sure if the oxidation will affect the backbone of the peg molecule. Give it a try. 
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Does anyone know how to dissolve CdTe coated with COOH in powder form in water or, alternatively in PBS ?
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Hello, 
If your QDs are surface derivatized with carboxyl groups, their solubility should be enhanced at high pH. (at least a couple of units above the pKa of the carboxylic acid bound to the surface of the nanoparticles.  They may take a while to dissolve if they come from a powder form. This is because they may be aggregated into lumps bound by hydrogen bridges formes among carboxyl groups of particles in near contact.
Try dissolving them at the highest pH that is safe. Use a strong base like 1 mM of NaOH. If they disolve then lower the pH slowly until they precipitate out of solution.
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How to recycle solvents (ester) polluted by cadmium 2+?
I have one suspension of Solvent + cadium2+. Are there some way to separate cadmium? Filter sistem? or Chemical system?
thanks at all ...
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Ion exchange
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Hello, I am trying to perform ELISA on glass slide; however I need to do carboxyl group activation of glass slide for Antibody immobilization. 
I am having thioglycolic acid (TGA) in lab and have done bioconjugation of dots to antibody using TGA. So, was thinking to go for the same chemical for  antibody attachment to glass slide.
Can anyone suggest me if this will work for carboxyl activation of glass slides?Thanks
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Thanks Omar Gonzalez, I have earlier tried Ab conjugation to glass slide using TEPSA (3-(TRIETHOXYSILYL)PROPYLSUCCINIC ANHYDRIDE)  which has silica group and binds to glass via Si-O-Si linkage and then carboxyl group of TEPSA binds to Ab via carbodiimide chemistry. But right now not having TEPSA so was thinking to do the same using TGA . But have not tried with APTES and glutaraldehyde; will look for this one also. 
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dear all
can anyone help be in selectively protecting the e-amino group in lysine as I wish to perform acylation of a-amino group iin lysine .
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Look at the procedure for compound 36, it's very straightforward.
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Does anyone have insight into modeled or experimental work that studies the density of water molecules at hydrophilic surfaces that are exclusively functionalized with specific oxygen containing groups (i.e. ketones, alcohols or carboxylic acids) to assess the functional groups oxidation state on water hydration layer formation?
Thank you for your help in advance.
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I appreciate the response however I am not finding that publication could you post a link?
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I have synthesized  TOPO  coated quantum dots in toluene. I want to make it water soluble. I tried phase transfer technique. I used 3-MPA  to transfer in to water. When I add water in organic medium containing particles, it immediately looses luminescence. It lost luminescence even with the addition of MPA alone after some time. I thought this might be due to poor surface passivation. I tried to synthesize particles in presence of TOPO and Octadecyl amine. However, the particle yiled is very low and the luminescence of particle is very poor or none. How  can I get rid of this problem. Thanks in advance for suggestions.
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Thanks Jose. perhaps, I will try silica coating at first.
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Can someone suggest a way to functionalize S- groups on activated carbon surface with strong bond give reference?
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thank you for your answer
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Hi all. 
Currently, I am synthesizing the gold-coated silica ( 0.5mm < d < 1mm) for GEM (gaseous elemental mercury) analysis. We have successfully synthesized the product that matches the physicochemical properties described in numerous preceded researches. Our work is mainly based on the paper I attach below. 
The next intention of our group is to co-precipitate PtNPs (platinum nanoparticles) alongside with AuNPs to create a Pt-AuNPs coated silica product.
I myself have referred to the one-pot synthesis of Pt-AuNPs where they use ascorbic acid-meditated reduction for the [AuCl4]- and [PtCl6]2- mixture, and I will use the procedure for the nanoparticle synthesis. I'm just not so sure the newly-formed Pt-AuNPs would be grafted on the silica surface, using ATPMS ((3-aminopropyl)trimethoxysilane) 1% v/v in methanol as the adhesive.
I am looking to hearing your opinion and willing to respond to any answer.
Thank you so much in advance.
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Dear Minh,
the adsorption of gold nanoparticles on aminosilanized surfaces is based on electrostatic attraction of negatively charged AuNP on a positively charged aminosilanized surface. Thus, if your AuPt-NP are as well negatively charged it should be no problem to deposit them on the aminosilanised silica. You could check the charge of the synthesized particles by measuring the zeta-potential of the NP-solution and then decide if adsorption would be successful.
Kind regards, Corinna
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I planned to coat certain antibody on the glass surface through EDC, NHS, (3-Aminopropyl)triethoxysilane. Before using antibody, I would like to try coating protein like albumin, lysozyme on glass. The question is, how do I show that those albumin, lysozyme are present and are covalently linked on the glass surface?
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This is an excellent question! Many researchers claim a complex covalent immobilization without giving any evidence. Particularly, aminosilanized surfaces are extremely sticky towards proteins: They bind proteins non-specifically, irrespective the covalent step works or not. To my knowledge, there is no simple way to distinguish strong non-specific from covalent immobilization. Some proteins might be eluted by SDS and or high-salt conditions. The most accurate way would be the cleavage of the protein from the surface, eg. by a high-pH solution, and subsequent analysis of the proteins by digest and LC-MSMS. However, this is very laborious.
For microarrays on glass slides, we prefer epoxysilanes which do not show such extreme non-specific binding. Unfortunately, this approach needs more time. High-salt conditions often improve this coating.
If you only want to quantify the amount of immobilized protein (irrespective of the mechanism), I would suggest amino acid analysis, which is sensitive and quite accurate, in contrast to most other protein detection methods.
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I need to choose a quite unique or new nanoparticles to increase membrane hydrophobicity. As far as I know, functionalized TiO2 and SiO2 have been widely used. The answer to the same question about a unique or new polymer is also appreciated. I would be grateful if you could share your ideas.
Thanks,
Mehdi
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I not completely understand, but CB is hydrophobic sicut ibi. Perfluorinated CB is superhydrophobic
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I'm looking for 200nm-500nm Magnetic Beads / Nanoparticles functionalized preferably with streptavidin. 
Most particles I've found are 'cluster-type' based beads with a very high dispersion of sizes.
Do you know companies that provide these?
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Dynabeads available from Thermo can come with a range of different functionalised surfaces, including streptavidin.
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I want to do confocal microscopy of nanoparticles with free carboxylic groups on the surface, what would be the best fluorescent dye with free amine group?
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Usually basic dyes are preferable for your method
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I was trying to hydrophobically modfiy a couple of polymeric surfaces using silane treatment. While they do show a higher contact angle for water after the treatment, they continue showing affinity for alcohol mixtures. Is this an expected phenomenon? I presume they continue liking alcohol due to its organic nature.
I was looking for information about surfaces/ surface modifications that can repel water and alcohol (ethanol or propanol) but not other organic compounds. Can someone please share some information about the same?
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As your contact angle for water has increased this definitely implies some kind of modification has occurred though not sufficient to repel the alcohol mixtures.
It is a simplification but in order for your surface to repel alcohols you need the surface energy of the polymer to be below that of the alcohol mix.
If you are measuring a surface energy ~80 degrees with water this would imply your surface probably has a surface energy of between 30 & 40 mN/m (use Owens-Wendt analysis with 2 or more test liquids if you want a more accurate SE value).
However, alcohols often have very low surface tensions (20-30 mN/m) compared with water (72 mN/m) so they will still wet the surface - you are most likely to succeed using fluoro-modified silanes or polymer coatings - as suggested above. In particular, long alkyl-chain fluoro-modified silanes often have very low surface energy values. A problem with fluoro modified polymers is that they are by nature Teflon-like (i.e. non-stick) and will not adhere well to your polymer without bridging groups, etc.
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I want to functionalize SiO2 coated silicon wafer by normal procedure in Lab. 
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The procedure of Abhishek is a good example of "know-how" and will work quite well especially for the basic APTES. If you keep the mechanism in mind (siloxane publication) multiple other ways will also lead to the goal (You need water and catalyst and a thin primer layer). I suggest using a less toxic, residue-free cleaning procedure (like H2O2/H2SO4) and a gase phase siloxanisation (acid surface and humidity works quite well) This a very simple, fast procedure using a desiccator, silane, reduced pressure and an (acid activated or a new) cleaned wafer surface, SiO2 (and atmospheric humidity). I also published some influences of "dry"(new) and "wet"(acid surface) preparation using APTMS and APTES resulting in m-APS.
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It is easier to machine the irregular microstructured surface than the regular one, thus leading to a lot of unknown surface function for advanced application.
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The liquids used homogenization step are accelerated the formation of BaTiO3 dependent on the O-H bands of the liquids structure. More O-H bands increased the density of the calcined powders, and improved the microstructure of sintered BaTiO3 ceramics. The density of the calcined powders is 4.67, 3.66, and 3.49 g/cm³ for the water, methanol, and acetone respectively. X-ray Diffraction (XRD) and Raman spectroscopy analysis were verified the structure of BaTiO3. The differences of the microstructure are clearly shown that the micrographs of sintered pellets by Scanning Electron Microscopy (SEM). Depending on the liquid, the process led directly to normal and abnormal grain growth of the sintered samples.
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I am thinking of this : surface coverage  = (weight loss of modified NP – weight loss of non modified NP) / (weight loss of modified NP). Thank you
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This formula does not look correct to me. Assuming 0% weight loss for nonmodified particles would give you 1 as a result.
For surface coverage you should know the size of your nanoparticles to calculate the surface area. From the weight loss and the residual mass, measured by TGA, you can calculate the molar amount of ligands and the total surface area. This will give you then a surface density (molecules/area).
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Cathodic cleaning which takes place in GTAW with AC polarity helps in welding reactive metals as during DCEN cycle the surface oxide layer gets cleaned and during DCEP cycle welding takes place. Why cant we achieve the same in other arc welding processes?