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Capillary action of water (polar) compared to mercury (non-polar), in each case with respect to a polar surface such as glass (≡Si–OH). Capillary action (sometimes called capillarity, capillary motion, capillary rise, capillary effect, or wicking) is the process of a liquid flowing in a narrow space without the assistance of external forces like gravity.
The equation is derived for capillary flow in a cylindrical tube in the absence of a gravitational field, but is sufficiently accurate in many cases when the capillary force is still significantly greater than the gravitational force. In his paper from 1921 Washburn applies Poiseuille's Law for fluid motion in a circular tube.
Capillary electrophoresis (CE) is a family of electrokinetic separation methods performed in submillimeter diameter capillaries and in micro- and nanofluidic channels.Very often, CE refers to capillary zone electrophoresis (CZE), but other electrophoretic techniques including capillary gel electrophoresis (CGE), capillary isoelectric focusing (CIEF), capillary isotachophoresis and micellar ...
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 in membranes [ 1 ] nonwovens ...
Flow through the pores in an oil reservoir has capillary number values in the order of 10 −6, whereas flow of oil through an oil well drill pipe has a capillary number in the order of unity. [ 4 ] The capillary number plays a role in the dynamics of capillary flow ; in particular, it governs the dynamic contact angle of a flowing droplet at ...
As all blood vessels allow a degree of protein leak , true equilibrium across the membrane cannot occur and there is a continuous flow of water with small solutes. The molecular sieving properties of the capillary wall reside in a recently-discovered endocapillary layer rather than in the dimensions of pores through or between the endothelial ...
Capillary pressure can also be utilized to block fluid flow in a microfluidic device. A schematic of fluid flowing through a microfluidic device by capillary action (refer to image of capillary rise of water for left and right contact angles in microfluidic channels) The capillary pressure in a microchannel can be described as:
Electro-osmotic flow is most significant when in small channels, and is an essential component in chemical separation techniques, notably capillary electrophoresis. Electro-osmotic flow can occur in natural unfiltered water, as well as buffered solutions. Electro-osmotic flow schematic