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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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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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Computational method to model the interactions between a liquid, a solid surface and particles on it?

I’m looking for a way to model the interactions between a liquid, a surface and various particles over the surface, in order to simulate the cleaning of said surface with different substances. My ...
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Why are lyophillic sols uncharged and lyophobic sols charged?

Gums, resins, glue, gelatin starch are uncharged and lyophillic where as metal sulphides and hydroxides are charged and lyophobic. Right after studying o-chem this seemed quite contradictory as ...
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How does critical temperature affect adsorption?

I don't really understand how does a high critical temperature favour adsorption? What I think is that the lower the temperature, more easy is it for the gas to liquefy and therefore adsorption is ...
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Why do bubbles form on the side of a plastic bottle?

I have a plastic bottle filled with drinking water where only one side of the bottle has air bubbles. I know that water is not pure and there are dissolved gases, and my theory is that there are small ...
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How can I make an alloy wetter?

I'm trying to make a Bismuth-Indium based low-melt alloy wetter (specifically, better at wetting to solid metals and glass). I've tried adding gallium, which obviously works, but due to its metal-...
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What is the effect of temperature changes on rate of chemisorption?

In chemisorption, if temperature increases, then after some time why does its rate decrease? I tried to explain it by Le Chatelier's principle but I don't believe it's valid as chemisorption is ...
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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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Is it possible to prevent agglomeration and sedimentation of microparticles just by increasing the viscosity of the medium?

I am considering a suspension of a fine powder in a high-viscosity liquid. The suspension shall be stable over long time scales, i.e. the particles only move a few mm per year, and I have the ...
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Phosphonate reaction with oxides and their stability?

I have read some papers stating that $\ce{SiO2}$ surfaces can bind phosphonates, but in water they hydrolyse. However, for $\ce{Si}$ surfaces, they are stable in water. In both cases, the reaction ...
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A question about “post it note”

I dipped a sticky note in water and there was a clear difference between the water absorption in the area with glue and the one without glue. The area with glue was more damp than the one without it. ...
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Mechanism behind colloidal suspension

There are two most common ways to stabilize colloids -- electrostatic stabilization and steric (or polymer mediated) stabilization. To my understanding, most of the electrically stabilized ...
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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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268 views

Activation energy in physical adsorption

Physical adsorption of molecules on surface requires activation energy, because bonds of the adsorbed molecules are broken. Is this a valid statement? I have been under the assumption that physical ...
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Does BET theory apply to type H3 and H4 isotherm for calculating surface area? [closed]

BET applies to type 2 and 4. That is basically unanimous.
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Influence of vapor pressure on surface tension

How does a liquid's vapour pressure affect its surface tension? i.e. to say, if a liquid's vapour pressure increases, will the surface tension increase or decrease? The SERP for this question yields ...
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Reaction Kinetics and Catalyst Addition

The addition of a catalyst is known to increase the rate constant of a reaction by providing an easier pathway for the reaction to occur, one with lesser activation energy. My doubt is: Is it ...
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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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“Nitrogen (gas) is physisorbed over iron (metal) at room temperature”: Is this for real? [closed]

My copy (PDF) of Levine's Physical Chemistry (6th ed.), page 570-571, section: "Adsorption of Gases on Solids", states: Physical adsorption is nonspecific. For example, $\ce{N2}$ will be physically ...
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How to avoid oxidation of Si using a sub nanometer layer

Does anyone know how and which material to use to protect a Si layer from Oxidation by a small layer of thickness less than 1 nm ? (probably using atomic layer deposition)
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What system of nomenclature can I use to indicate the positions of specific kinds of atoms of a surface reconstruction?

I was reading a journal based on SiC reconstructions, and they seem to mention that every dangling bond in the $(1\times 1)$ unreconstructed Si face or the $(0001)$ direction bonds up with a Si adatom ...
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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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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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Can negative adsorption be considered equal to sorption?

In my book it was written sorption is basically when the substance gets uniformly distributed into the bulk of the solid but at the same time its concentration is higher at the surface then in the ...
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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 ...
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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 ...
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How can I measure a droplets contact angle without a setup?

I have to use a phone camera to replicate the Sessile drop analyzer, but there doesn't seem to be a standard to different parameters, such as how far away should my camera be from the droplet or how ...
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Functionalizing CTAC stabilized nanoparticles

I am working on functionalizing silver-gold bimetallic nanoparticles. My nanoparticles are stabilized by CTAC(cetyltrimethylammonium chloride).The most articles which I found, are about the ...
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Substances comprised of large molecules are liquids at room temperature?

I am looking for compounds that are liquid at normal temperatures and are physically very large, to be used in an ellipsometer adsorption experiment. I am currently working with decane. The candidates ...
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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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Conductive hydrophobic material

I was looking for a conductive hydrophobic material if there is one? If not why? I was researching and I found some material about laser etching on metals that causes superhydrophobicity but that I ...
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Crystallisation and crystal surface

It is my understanding that if you put table salt (as an example of polar compound) in water, the Na+ and Cl- ions will freely move through the solution. They will make the solution conductive and ...
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Mixing water and oil in microgravity outside of a container

What would happen if I where to mix water and oil in a vacuum in microgravity where the temperatures were low enough so that the oil and water remain liquids also, the mixture is not inside of a ...
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How does physical adsorption of mixed gas occur on solid? (eg I mean how the gas molecules of compete each other for a slot on solid surface)

I am working on sorption phenomenon of gases (including inert gas) on coal seam surface. For a mixture of 2 gases at a certain pressure, carbon dioxide and methane, for instance, $\ce{CO2}$ is ...
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Very fast brass oxidation

I work for a company that manufactures pyrotechnics for the oil and gas industry, and we have been having an odd phenomenon occur. One part, a brass tube with a copper clip filled with black powder, ...
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How fast a surface oxide layer is formed on bulk chromium?

If a chromium piece is cut in half, how long would it take for an oxide layer to form on the new surface (room temperature)? i.e. is it a matter of seconds/minutes/hours/days/weeks? The closest study ...
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How to create a Non Water loving Vegatable Oil Foam?

I am trying to create a vegetable oil foam (or large quantity of air bubbles) and as I am not a Chemist by far. First I was thinking of using Amphiphilic surfactant, but I don't want this foam to be ...
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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 ...
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What is a typical monolayer formation time for liquid phase adsorbate on a solid surface?

Let's say a solid is submerged in a solution of species with functional groups and a self-assembled monolayer is forming. What are the typical time scales for the formation of a continuous monolayer? (...
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What is the surfactant's role in the non-coalescence of water droplets?

I have recently seen many videos that talk about the noncoalescence of water droplets; however, I do not understand the purpose of adding surfactants into the water. From my knowledge (high school), ...
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Why non polar liquids wet non polar surfaces better than polar surfaces?

In semiconductor industry adhesion promoters (such as HMDS) are applied on various surfaces to improve adhesion between the surface and the photoresist: On SiO2 and many metals surfaces, the air ...
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What chemical would best adhere rubber to concrete and/or asphalt?

There are already mixtures in place that work well but I'm wondering if there is something better than is currently being used. http://www.jegs.com/p/PJ1/PJ1-Track-Bite/749307/10002/-1 http://www....
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Surface Tension and Evaporation

Why does acetone evaporate faster than ethanol yet still has a higher surface tension? I would expect it to have a lower surface tension... I got the data from surface-tension.de.
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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 ...
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Overall equilibrium expression for competitive equilibria

I have a case where I have two reactions that depend on a common reactant. The reactions can be written as: I) $\ce{A + B <=> AB}$ II) $\ce{A + C <=> AC}$ We can thus write equilibrium ...
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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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Why does the BET equation take into consideration a multimolecular-layer, even though it deals with chemisorption?

I came across the Brunauer-Emmet-Teller (BET) equation recently, and one thing that I found strange was an implicit reference to the formation of molecular multi-layer. In the BET equation $$ \begin{...
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A surface with variable roughness

As you may know, wettability is a characteristic of each surface which determines what the contact angle would be when a droplet is put on the surface (see here for more info). Surface roughness has a ...
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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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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: $ \...