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Capillary flow porometry, also known as porometry, is a characterization technique based on the displacement of a wetting liquid from the sample pores by applying a gas at increasing pressure. It is widely used to measure minimum, maximum (or first bubble point) and mean flow pore sizes, and pore size distribution of the through pores in membranes nonwovens, paper, filtration and ultrafiltration media, hollow fibers, ceramics, etc. In capillary flow porometry an inert gas is used to displace a liquid, which is in the pores. The pressure required to empty the pore corresponds to the pressure necessary to evacuate the liquid from the most constricted part of the pore. This most constricted part is the most challenging one and it offers the highest resistance to remove the wetting liquid. This parameter is very relevant in filtration and similar applications since it is important to know the smallest diameter of the through pores. ==Calculation of the pore size== In order to measure the pore size by capillary flow porometry it is necessary to impregnate the samples with a wetting liquid. An inert gas flow is used to displace the liquid that is in the pores and the pressure required to empty the most constricted part of the pore is measured. The most constricted part of the pore is the most challenging one because it offers the highest resistance to remove the wetting liquid. This parameter is very important in filtration and similar applications since it is essential to know the smallest diameter of the through pores. This measured pressure permits obtaining the pore diameter, which is calculated by using the Young-Laplace formula P= 4 *γ *cos θ */D in which D is the pore size diameter, P is the pressure measured, γ is the surface tension of the wetting liquid and θ is the contact angle of the wetting liquid with the sample. The surface tension γ is a measurable physical property and depends on the wetting liquid used. The contact angle θ depends on the interaction between the material and the wetting liquid. 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 simplied as: P= 4 *γ/D. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Capillary flow porometry」の詳細全文を読む スポンサード リンク
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