How does Langmuir trough work?
A Langmuir–Blodgett trough (LB trough) is a laboratory apparatus that is used to compress monolayers of molecules on the surface of a given subphase (usually water) and measures surface phenomena due to this compression. It can also be used to deposit single or multiple monolayers on a solid substrate.
What does the Langmuir isotherm show?
The Langmuir isotherm describes the maximum amount of gas that a shale can hold at a specified pressure and temperature. Several factors may result in a shale holding less than the maximum amount of gas as represented by the isotherm. Such shales are termed undersaturated.
What assumptions are made in the Langmuir model?
Basic assumptions of the model The adsorbing gas adsorbs into an immobile state. All sites are energetically equivalent and the energy of adsorption is equal for all sites. Each site can hold at most one molecule of A (mono-layer coverage only). No (or ideal) interactions between adsorbate molecules on adjacent sites.
What is Langmuir-Blodgett method?
The Langmuir-Blodgett (LB) technique is a way of making supra-molecular assembly in ultrathin films with a controlled layered structure and crystal parameter, which have many envisioned technological applications for optical and molecular electronic devices as well as signal processing and transformation.
What is the Langmuir adsorption constant?
The Langmuir constant (K) indicates the extent of interaction between adsorbate and the surface. If the value of K is relatively larger it indicates that there is a strong interaction between adsorbate and adsorbent while smaller value implies a weak interaction.
What are Langmuir-Blodgett films used for?
Langmuir Films are thin organic films of a thickness of just one molecule and are the source of high expectations. As useful components in many practical and commercial applications such as sensors, detectors, displays and electronic circuit components.
What is the difference between Langmuir and Langmuir Blodgett film?
When a monolayer is fabricated at the gas-liquid or liquid-liquid interface, the film is a Langmuir film. A Langmuir film can be deposited on a solid surface and is thereafter called Langmuir-Blodgett film (in the case of vertical deposition) or Langmuir-Schaefer film (in the case of horizontal deposition).
How do you find the slope of a Langmuir graph?
Using the formula qe=(Ci−Cf)Vmass of adsorbent, and then plot the graph 1qe versus 1Cf. It would be easier by using excel. From the graph, we can calculate the slope. The linear graph will produce y=mx+c equation.
How do you find the surface area of a Langmuir?
Using the nonlinear Hanes transformation we get x/y=1/K+x and then (p/ps)/V=1/(VmK)+(p/ps)/Vm. Thus, using the slope (1/Vm), Vm can be easily determined and then the surface area.
What is Langmuir surface area?
BET surface area is measured by specific surface area of the adsorbent. BET surface area is measured by using non-corrosive gases like N2, CO2, Ar etc. BET surface area depends on size and number of gas molecules adsorbed. Langmuir surface area depends on adsorption capacity of the adsorbent.
How do you derive Langmuir adsorption isotherm?
Derivation of the Langmuir isotherm
- [SA] is proportional to the surface coverage of adsorbed molecules, or proportional to q.
- [S] is proportional to the number of vacant sites, (1 – q)
- [A] is proportional to the pressure of gas, P.