Questions tagged [surface-chemistry]

Surface chemistry is roughly defined as the study of chemical reactions at interfaces between 2 or more phases.

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33
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9answers
11k views

Would it be possible to destroy gold?

I'm a writer. I have a scenario in which a sizable amount of gold needs to be rendered unusable, preferably completely destroyed. I know an acid like aqua regia is able to dissolve gold, but would ...
33
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2answers
1k views

How does the silver nucleate on glass in Tollen's reagent mirroring?

I want to know the exact mechanism for how silver would start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how I see the nucleation/growth process of silver ...
29
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4answers
8k views

Is "stainless" a bulk or a surface property of stainless steel?

In particular, if I cut a block of stainless steel in half, would the newly formed faces be stainless as well?
21
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2answers
6k views

What is the edge of a diamond like?

The chemical structure of a diamond is defined as an endless lattice in which each carbon atom is covalently bonded to four other carbon atoms situated at the four ends of a tetrahedron. But of ...
17
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1answer
668 views

What is the chemistry behind this "petrol from air" technology?

A recent news report in the UK claimed a breakthrough in making a petrol equivalent from carbon dioxide and water: A small British company has produced the first "petrol from air" using a ...
16
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5answers
25k views

Why is Charcoal such an excellent adsorbent?

Charcoal (also activated charcoal) is known to adsorb a huge variety of substances including a variety of paints, dyes and many different kinds of ions. Moreover, the amount of adsorption at normal ...
15
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3answers
6k views

How does chromium help stainless steel prevent rusting?

Various sources (such as this one) say that stainless steel is stainless because a passivation layer of an oxide is formed, but I haven't found details on why chromium helps create this passivation ...
15
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1answer
7k views

What is the mechanism of APTES mono-layer formation on glass substrates?

The reagent APTES is a fairly common "ink" for microcontact printing, a technique that forms covalent bonds between the silanols found on the surface of the glass and the silane in the the APTES. It's ...
13
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2answers
59k views

Hardy Schulze law

I have trouble understanding this particular law. It states that: Greater the valency of the flocculating ion, greater will be its coagulation power. Why does this happen? What is the intuition ...
13
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2answers
3k views

How to remove stain from pavement after having dropped sulfuric acid on it?

I had this car battery that flipped in my car trunk. When I got it out of there it spilled some acid on the pavement. It's a sulfuric acid battery. I added some baking soda on it and poured some more ...
13
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1answer
1k views

Reaction mechanism in fluoride adsorption to aluminum oxide

Despite a fair amount of research (excluding non-open access journals, to which I have not got access), I cannot seem to find an explanation of the process that takes place when $\ce{F^-}$ adsorbs to ...
13
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0answers
179 views

Can pi backdonation occur on non-metal centers?

The common example of back-donation is the interaction of a CO molecule with a metal center (d-orbitals) on a surface. Can a similar mechanism occur between CO and a non-metal center, like oxygen on ...
12
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1answer
8k views

Is adsorption exothermic, and if so, why?

Why is adsorption exothermic? The explanation given in my textbook is: For a process to be spontaneous, the thermodynamic requirement is that, at constant temperature and pressure, $\Delta G &...
11
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2answers
2k views

Methods for Determining Partial Charges

I want to run classical molecular dynamics simulations of a periodically replicated surface (rutile $\ce{TiO2}$ with grooves). In order to do so, I first need to solve for the partial charges residing ...
11
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1answer
563 views

How to simulate surface tension?

I am trying to create a water drop simulation for measuring hydrophobicity of surface. I don't know how to simulate the contact angle which is related by younges equation to the surface tensions for ...
10
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4answers
2k views

Where does the potential energy of capillary action come from?

Capillary action is when water pulls itself up a paper towel, glass tube or a tree. It is going up, which results in an increase in potential energy. According to the law of conversation of energy, ...
10
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4answers
3k views

How does polydimethylsiloxane stick to glass?

Polydimethylsiloxane (PDMS) is the main ingredient in Rain-X, a treatment that adheres to windshields. How does PDMS adhere to class? It can't form covalent Si-O bonds with glass, according to one ...
10
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6answers
11k views

Why does chemisorption increase with rise in temperature, even though it is an exothermic process?

Chemisorption is exothermic process, but still it increases with increase in temperature. Why? I know that there needs to be a minimum activation energy to be achieved in order to initiate ...
9
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1answer
6k views

What forces hold ink on paper?

On regular paper, ink is absorbed, while on photopaper ink stays at the surface and dries for a longer time. What forces act in these two different cases? (see also related questions about pencil ...
9
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1answer
260 views

Transition state optimisation on the surface of periclase

I want to model a reaction catalysed by periclase ($\ce{MgO}$) using DFT. I have a good guess on the transition state (TS) of the reaction that goes in gas phase/solvent (produced using MOPAC). The ...
9
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1answer
6k views

Treatment of copper (0) with sodium hydroxide

I recently made self-assembled monolayers (SAMs) of alkanethiols on a copper substrate. After scrubbing off the $\ce{Cu2O}$ top layer and rubbing the surface with ether and ethanol, I let my copper ...
8
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1answer
675 views

Why are van der Waals' forces between gas molecules strong near its critical temperature?

My textbook says …easily liquefiable gases i.e. with higher critical temperatures are readily adsorbed as van der Waals' forces are stronger near the critical temperatures. What I do understand is ...
8
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1answer
309 views

When using LPCVD, is it possible to pattern a silicon wafer with poly-silicon using a mask?

I know it's possible to etch (i.e. pattern) poly-silicon, but I'm curious if one can just use a mask instead. Are there masks that inhibit the growth of poly-silicon?
8
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1answer
97 views

Retention of surface texture after combustion

Just some while ago I was burning a box of cardboard in my backyard and I saw a very curious phenomenon. I saw that as the cardboard box started burning it started to curl. Up after a while as I ...
8
votes
1answer
91 views

If something is not hydrophilic, is it necessarily hydrophobic?

Is it possible to create hydrophobic water? Two species are phobic within some medium under some conditions when they don't here together (cohere if they're the same species; adhere otherwise). To be ...
8
votes
1answer
287 views

Stripeless cleaning of windows

Last week I was discussing with a friend how we thought the stripeless cleaning of windows is achieved when using a cleaner like Windex Glass Cleaner as opposed to just using hot water, in which case ...
8
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1answer
219 views

Organic solutions that corrode metals

Most of the common organic solvents are regarded as noncorrosive, but stainless steel can be attacked by formic, acetic, and propanoic acids. Corrosion of stainless steel by organic solvent mixtures, ...
8
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1answer
453 views

Consequences of using reagent preserved with sodium azide on gold film

I am running experiments using reagents preserved with 0.1% sodium azide, which are applied to a gold film. Unfortunately, there are very few options for using reagents without sodium azide. I ...
7
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4answers
387 views

Varying potential diffrence between two graphite strips in NaCl solution

I have two identical graphite strips of dimensions 3.5 cm by 1 cm. Both are 3/4 submerged in aqueous $\ce{NaCl}$ solution (0.34 mol/dm$^3$, 2% wt) separated by a distance of 7 cm. I have attached ...
7
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0answers
501 views

Does phosphoric acid remove stainless steel electropolished layer?

Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide. Phosphoric acid is ...
6
votes
1answer
231 views

Why does Freundlich adsorption isotherm not have a term for surface area?

Why does Freundlich adsorption isotherm not have a term for surface area? The formula given by Freundlich adsorption isotherm: $$ \frac{x}{m}= k P ^{1/n}$$ Where $x$ is the mass of gas adsorbed ...
6
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1answer
443 views

What, if any, are the differences between hemiwicking and wicking?

I'm encountering these two terms, but their uses seem to be different, and there's little documentation out there defining the terms. Here is an example definition I've found of Wicking: Wicking ...
6
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1answer
2k views

Materials that resist adhesion with molten glass even when hot

I'm looking for ways to manipulate molten glass with (e.g. bending a heated glass tube). This article mentions that oxides tend to adhere, hence molten glass to heated stainless steel. What ...
6
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1answer
209 views

How to dissolve composite In2O3 with SnO2 without affecting stainless steel?

I found this article, but it was not helpful. The $\ce{In2O3}$ is probably amorphous. $\ce{HNO3}$ and $\ce{HCl}$ do not work. Any ideas?
5
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1answer
484 views

Is the surface of glass a fine layer of silanol?

Today we learned in class through a vivid demonstration that water sticks to glass. We were then taught that water sticks to glass because while glass is mainly composed of silicon dioxide, the ...
5
votes
1answer
2k views

What is the chemical structure of ceramic nonstick coating on pans?

There are lots of pans nowadays that have a ceramic nonstick coating instead of a PTFE coating. However I can not find anything online describing what kind of ceramic such nonstick coatings are. Does ...
5
votes
1answer
223 views

Surface Functional Groups/Notation

I'm reasonably unfamiliar with chemical notation, and recently I've come across something I'm not sure how to interpret. In this article, the authors refer to the "surface groups" denoted by $\ce{#Ti-...
5
votes
1answer
947 views

Kinetic energy of electrons emitted in Photoelectron Spectroscopy

In multiple sources (example), I found the information that the kinetic energy $E_k$ measured using (Ultraviolet / X-ray) Photoelectron Spectroscopy is given by: $E_k = h\nu - B.E._F - \phi_{spec}$ ...
5
votes
0answers
61 views

Thermodynamics of micellisation

Micellisation is found to be spontaneous i.e. $\Delta G < 0.$ It's found that $\Delta S > 0,$ which was intuitive since, solvated molecules are released. And, it may be most loosely started that ...
5
votes
0answers
379 views

Helmholtz double layer

I don't quite understand what is meant by the Helmholtz double layer. Textbooks states something along the lines of: the colloidal particles attain charge by selective adsorption, due to this it ...
5
votes
0answers
59 views

Computational modeling of steric repulsion between two polymer mediated magnetic Nanoparticle?

Can you recommend any modern article or research papers on steric interactions and forces between two or multiple magnetic nanoparticles with polymer brushes in a nonpolar solvents? something with ...
4
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1answer
4k views

Does adsorption violate thermodynamics?

My textbook reads as follows: When a gas is adsorbed, the freedom of movement of its molecules become restricted. This amounts to decrease in the entropy of the gas after adsorption, i.e. Entropy ...
4
votes
2answers
103 views

LEED - determining surface structures

How can one describe surface structures (before and after adsorption)? I understand the diffraction theory but I have never really tried to determine the structures of samples by myself. LEED (low ...
4
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1answer
702 views

Effect of solutes on surface tension

What happens to the surface tension of a solvent, say, water when we mix a solute in it? For the sake of concrete discussion, the examples that I encountered in a test were sodium chloride $(\ce{NaCl})...
4
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3answers
12k views

The entropy change during micellization

I was reviewing the thermodynamics of micelle formation from the Wikipedia page and this book. I understood most of the arguments but micellization is supposed to be an entropy driven process with a ...
4
votes
1answer
168 views

How does water freeze and crystallize on a cold superhydrophobic surface?

Superhydrophobic surfaces are nano-structured to "repel" liquid water and there has been a lot of work done to understand the microscopics of wetting of these nanostructures. What I currently am ...
4
votes
1answer
141 views

Using results of current experiments in silanization, how to achieve a higher contact angle?

I've done several silanization tests with different solutions and here is a brief of my results: DichloroDimethylSilan: Advancing=90, Receding=56 ChloroTrimethylSilan: Adv=91, Rec=70 ...
4
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1answer
90 views

Nanocar racing competition and the race tracks used

In the Nanocar race competition the molecules are raced on a gold surface. Is there a specific property of gold that it forms a good "racetrack"? On what criteria does it compare with other metal ...
4
votes
1answer
43 views

Practical to measure topography of a large area (mm-scale) with scanning probe microscopy (SPM)?

I'm currently very new to nanotechnology. I do understand that it is possible to achieve an excellent topography image of a sample by SPM. However, is it possible to do SPM over a large area (for ...
4
votes
1answer
862 views

How does a Brunauer–Emmett–Teller device function?

The Brunauer–Emmett–Teller (BET) theory is comprehensible. My question is more geared towards what is physically and chemically happening within a BET device to get a reading? How does a BET device ...

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