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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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Properties of Nanocar racetracks

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 ...
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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
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What decides the nature of emulsifying agents?

I read The emulsifying agent forms an interfacial film between suspended particles and the medium. The principal emulsifying agents for O/W emulsions are proteins, gums, natural and ...
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Calculating pre-exponential factor using transition state theory

I would like to calculate the pre-exponential factor of a surface reaction using transition state theory. I've seen two ways to calculate it but I get different answers for each method (and I don't ...
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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
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 ...
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4answers
138 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, ...
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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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How do lyophilic sols protect lyophobic sols?

How are lyophobic sols prevented from coagulating when lyophilic sols are added to them? I tried to search for the answer but didn't get a plausible explanation anywhere.
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Surface Chemistry - Dipole Moment of Surfactant with Water and Phases of a Monomolecular Layer

Recently, I have been trying to study surface chemistry and I have come across questions that I do not understand how to answer. I understand what a dipole moment is, defined as a charge separation ...
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3D printing of alumina

I want to print a structure of alumina, and the 3D printer that I am using is an extrusion-based printer. So I need your help in knowing that what composition (binders and deflocculant) of alumina ...
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1answer
55 views

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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1answer
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Adhesion of polymerized fats to cast iron

I'm trying to make an informed decision as to which oil is best to use for cast iron seasoning. I've read all kinds of conflicting information online and the only consistency seems to be that ...
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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
36 views

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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1answer
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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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1answer
127 views

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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1answer
228 views

How to disperse salicylic acid in sodium lauryl sulfate solution? [closed]

Anti-dandruff shampoo contains salicylic acid as an active ingredient, but when salicylic acid powder comes in contact with a base solution such as sodium laurylsulfate and water (1:3 wt/wt) caking of ...
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1answer
356 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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Why we have mass of adsorbent in Freundlich equation?

In Freundlich equation why we have $m$ the mass of adsorbent. I mean it is surface chemistry and on the surface of adsorbent the adsorption takes place so why we have mass of adsorbent in that ...
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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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1answer
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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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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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0answers
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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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1answer
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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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1answer
200 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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0answers
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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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1answer
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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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3answers
6k 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 ...
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1answer
3k views

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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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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2answers
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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
351 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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2answers
229 views

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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1answer
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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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1answer
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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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1answer
55 views

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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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
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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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1answer
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Do bond energies differ for surface and bulk atoms in nanoparticles?

In nano-particles, surface atoms have fewer neighboring atoms in compare to bulk atoms. Is there any difference between bond energy of surface atoms and bulk atoms?
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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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1answer
693 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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1answer
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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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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 ...