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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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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 ...
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2answers
4k 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 ...
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1answer
566 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 ...
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577 views

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

I'm trying to figure out how exactly does the silver 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 on ...
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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 ...
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1answer
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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 ...
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1answer
692 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 ...
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5answers
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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 ...
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1answer
5k 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 &...
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3answers
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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 ...
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1answer
397 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 ...
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2answers
1k 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 ...
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2answers
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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 ...
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1answer
3k 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 ...
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1answer
5k 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 ...
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6answers
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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 ...
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0answers
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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 ...
8
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1answer
251 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?
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1answer
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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 ...
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1answer
199 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 ...
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1answer
113 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,...
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1answer
365 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 ...
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4answers
317 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 ...
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1answer
407 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 ...
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1answer
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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?
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4answers
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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, ...
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1answer
359 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 ...
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1answer
155 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
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1answer
186 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 ...
5
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1answer
978 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
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1answer
697 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: $E_k = h\nu - B.E._F - \phi_{spec}$ ...
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0answers
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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 ...
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0answers
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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 ...
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1answer
102 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 ...
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1answer
110 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 ...
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1answer
348 views

Auto-catalysis Mechanism

I just read about the theory of auto-catalysis, and here's one thing which is sort of unclear to me: In this type of catalysis, one of the reaction product catalyses the reaction. For example, in ...
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1answer
287 views

Counterions in adsorption of ions

When an ion is adsorbed from an aqueous solution onto a solid, what happens to its counterion? Obviously, the solution does not become charged - does this mean that it too is adsorbed? (Example: $ \...
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1answer
201 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-...
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1answer
823 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 ...
4
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1answer
76 views

Influence of sodium cyanoborohydride on C=N bonds in DNA bases

I would like to crosslink an amino-modified DNA strand with an APTES monolayer (which also has a $\ce{NH2}$ end group) using a glutaraldehyde linker. After the formation of Schiff base linkages ...
4
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1answer
133 views

Soil-solution cations in competition for exchange sites

How could one determine the likelihood of one cation displacing another on a negatively charged exchange site of a clay particle? For example, in a soil solution containing equal parts (by number of ...
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1answer
2k 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 ...
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3answers
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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 ...
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1answer
5k views

Effect of pressure on adsorption of a gas

I am currently studying about the basic terms of surface chemistry, and am facing some conceptual doubt regarding the following: What effect does pressure have on the adsorption of a gas (adsorbate) ...
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2answers
153 views

How do we determine if some metal will undergo passivation under suitable environment?

The passivity of certain metal fall in order: $\ce{Ti->Al->Cr->Be->Mo->Mg->Ni->Co->Fe->Mn->Zn->Cd->Sn->Pb->Cu}$ Can we predict the order of passivation ...
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1answer
296 views

Chromatography: Why does the insoluble compound get pulled along?

In paper chromatography, we see that a paper with an ink spot on it get dissolved in the liquid and travels up with water due to capillary action. Then the compounds with more affinity to the paper ...
3
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1answer
280 views

Prediction of surface atoms in molecule from its graph

If we are given a molecular graph i.e. al the atoms involved and their connectivity, how can we make reasonable prediction if the atom would lie in the surface or in the inner part. On way might be ...
3
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1answer
45 views

Why does the surface of an acid appear to have a stronger “dissolving power”?

In this Periodic Videos YouTube video by Brady Haran and the University of Nottingham, we see a piece of gold being dissolved in aqua regia, while Professor Poliakoff explains why aqua regia can ...
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1answer
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What is the difference between BET and Langmuir model for calculating the specific surface area?

Brunauer–Emmett–Teller (BET) surface area is measured by specific surface area of the adsorbent. BET surface area is measured by using non-corrosive gases like $\ce{N2}$, $\ce{CO2}$, $\ce{Ar}$ etc. ...
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1answer
632 views

What is the definition of porous materials?

Is there a consensus on scientific definition of porous materials? There are many definitions out there which do not seem accurate enough: from wikipedia (accessed July 2017): A porous medium or a ...