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| A '''monolayer''' is a single, closely packed layer of atoms, molecules,<ref>{{cite journal |last1=Ter Minassian-Saraga |first1=L. |year=1994 |title=Thin films including layers: terminology in relation to their preparation and characterization (IUPAC Recommendations 1994) |journal=[[Pure and Applied Chemistry]] |volume=66 |issue=8 |pages=1667–1738 |publisher=[[IUPAC]] |doi=10.1351/pac199466081667 |url=http://pac.iupac.org/publications/pac/pdf/1994/pdf/6608x1667.pdf |accessdate=November 5, 2012}} On page 1672.</ref> or cells. In some cases it is referred to as a [[Self-assembled monolayer]].
| | I'm a 30 years old and working at the university (Neuroscience).<br>In my spare time I'm trying to teach myself Swedish. I've been there and look forward to go there sometime near future. I like to read, preferably on my kindle. I really love to watch The Vampire Diaries and Game of Thrones as well as docus about anything astronomical. [http://www.Adobe.com/cfusion/search/index.cfm?term=&I+enjoy&loc=en_us&siteSection=home I enjoy] Art collecting.<br><br> |
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| == Chemistry ==
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| A '''Langmuir monolayer''' or insoluble monolayer is a one-molecule thick layer of an insoluble organic material spread onto an [[aqueous]] sub[[phase (matter)|phase]]. Traditional compounds used to prepare [[Langmuir (unit)|Langmuir]] monolayers are [[amphiphilic]] materials that possess a [[hydrophilic]] headgroup and a [[hydrophobic]] tail. Since the 1980s a large number of other materials have been employed to produce Langmuir monolayers, some of which are semi-amphiphilic, including [[macromolecule]]s such as [[polymer]]s. Langmuir monolayers are extensively studied for the fabrication of [[Langmuir-Blodgett film]] (LB films), which are formed by transferred monolayers on a solid substrate. A [[Josiah Willard Gibbs|Gibbs]] monolayer or soluble monolayer is a monolayer formed by a compound that is soluble in one of the phases separated by the [[interface (chemistry)|interface]] on which the monolayer is formed.
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| === Formation time ===
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| The '''monolayer formation time''' or '''monolayer time''' is the length of time required, on average, for a surface to be covered by an adsorbate, such as oxygen sticking to fresh aluminum. If the adsorbate has a unity [[sticking coefficient]], so that every molecule which reaches the surface sticks to it without re-evaporating, then the monolayer time is very roughly:
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| :<math>t = \frac{3 \times 10^{-4} \, \mathrm{Pa} \times \mathrm{s}}{P}</math>
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| where ''t'' is the time and ''P'' is the pressure. It takes about 1 second for a surface to be covered at a pressure of 300 µPa (2×10<sup>-6</sup> Torr).
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| === Monolayer phases and equations of state ===
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| A Langmuir monolayer can be compressed or expanded by modifying its area with a moving barrier in a Langmuir film balance. If the surface tension of the interface is measured during the compression, a ''compression isotherm'' is obtained. This isotherm shows the variation of surface pressure (<math>\Pi = \gamma^o - \gamma </math>, where <math>\gamma^o</math> is the surface tension of the interface before the monolayer is formed) with the area (the inverse of surface concentration <math>\Gamma^{-1}</math>). It is analogous with a 3D process in which [[pressure]] varies with [[volume]].
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| A variety of bidimensional [[phase (matter)|phases]] can be detected, each separated by a [[phase transition]]. During the phase transition, the surface pressure doesn't change, but the area does, just like during normal phase transitions volume changes but pressure doesn't.
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| The 2D phases, in increasing pressure order:
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| * Bidimensional gas: there are few molecules per area unit, and they have few interactions, therefore, analogous of the [[equation of state|equations of state]] for 3D gases can be used: ideal gas law <math>\Pi A = RT</math>, where <math>A</math> is the area per mole. As the surface pressure increases, more complex equations are needed (Van der Waals, virial...)
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| * Expanded liquid
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| * Compressed liquid
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| * Solid
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| If the area is further reduced once the solid phase has been reached, collapse occurs, the monolayer breaks and soluble aggregates and multilayers are formed
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| Gibbs monolayers also follow equations of state, which can be deduced from [[Gibbs isotherm]].
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| * For very dilute solutions <math>\gamma = \gamma_o - mC</math>, through Gibbs isotherm another analogous of ideal gas law is reached <math>\Pi = \Gamma R T</math>
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| * For more concentrated solutions and applying Langmuir isotherm <math>\Gamma = \Gamma_{\max} \frac{C}{a+C}</math>, thus <math>\Pi = \Gamma_{\max}RT \left(1+\frac{C}{a}\right)</math>
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| == Biology ==
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| Monolayers are frequently encountered in [[biology]]. A [[micelle]] is a monolayer, and the [[phospholipid]] [[lipid bilayer]] structure of [[cell membrane|biological membrane]]s is technically two monolayers.
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| === Cell culture ===
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| In [[cell culture]] a monolayer refers to a layer of cells in which no cell is growing on top of another, but all are growing side by side and often touching each other on the same growth surface.
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| == See also ==
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| * [[Self-assembled monolayer]]
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| ==References==
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| <references/>
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| ==External links==
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| * {{cite web |url=http://goldbook.iupac.org/M04015.html |title=Monolayer |work=Goldbook |publisher=[[IUPAC]] |accessdate=November 5, 2012}}
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| [[Category:Phases of matter]]
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| [[Category:Thin films]]
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| [[Category:Physical chemistry]]
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I'm a 30 years old and working at the university (Neuroscience).
In my spare time I'm trying to teach myself Swedish. I've been there and look forward to go there sometime near future. I like to read, preferably on my kindle. I really love to watch The Vampire Diaries and Game of Thrones as well as docus about anything astronomical. I enjoy Art collecting.
Feel free to surf to my website; Fifa 15 Coin Generator; Gesinvalles.Es,