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Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter, total pore volume, surface area, and bulk and absolute densities. The technique involves the intrusion of a non-wetting liquid (often mercury) at high pressure into a material through the use of a ...
In capillary flow porometry, in opposition to mercury intrusion porosimetry, the wetting liquid enters spontaneously the pores of the sample ensuring a total wetting of the material, and therefore the contact angle of the wetting liquid with the sample is 0 and the previous formula can be simplified as: P= 4*γ/D.
Powder wettability measurement with the Washburn method. In its most general form the Lucas Washburn equation describes the penetration length of a liquid into a capillary pore or tube with time as = (), where is a simplified diffusion coefficient. [4]
Micro CT of porous medium: Pores of the porous medium shown as purple color and impermeable porous matrix shown as green-yellow color. Pore structure is a common term employed to characterize the porosity, pore size, pore size distribution, and pore morphology (such as pore shape, surface roughness, and tortuosity of pore channels) of a porous medium.
Water evaporation method (pore volume = (weight of saturated sample − weight of dried sample)/density of water) Mercury intrusion porosimetry (several non-mercury intrusion techniques have been developed due to toxicological concerns, and the fact that mercury tends to form amalgams with several metals and alloys). Gas expansion method. [6]
However, simple cooling of an all-liquid sample usually leads to a state of non-equilibrium super cooling and only eventual non-equilibrium freezing – to obtain a measurement of the equilibrium freezing event, it is necessary to first cool enough to freeze a sample with excess liquid outside the pores, then warm the sample until the liquid in ...
For example, if a container filled with water vapour at slightly below the saturation pressure is suddenly cooled, perhaps by adiabatic expansion, as in a cloud chamber, the vapour may become supersaturated with respect to liquid water. It is then in a metastable state, and we may expect condensation to take place.
BET model of multilayer adsorption, that is, a random distribution of sites covered by one, two, three, etc., adsorbate molecules. The concept of the theory is an extension of the Langmuir theory, which is a theory for monolayer molecular adsorption, to multilayer adsorption with the following hypotheses: