The so-called bubble point, the simplest principle can be understood as follows: Take a PTFE bubble point membrane of a certain material, moisten it with a certain solution, and then pressurize one side to isolate the gas of a certain pressure. increases, the gas is released from one side of the PTFE bubble point membrane, which appears as bubbles of varying sizes and numbers on one side of the membrane, and the corresponding pressure value is the bubble point pressure.
Further, more specific definitions such as bubble point pressure, group bubble point pressure, and total bubble point pressure can be given based on the order and number of bubbles appearing.
So the generalized bubble point pressure may be replaced by bubble point pressure, group bubble point pressure, full bubble point pressure, etc. in different understandings.
The reason for the above different understandings may be that there is no unified understanding of the physical meaning of gas flow across the membrane.
The bubble point pressure is the gas pressure at which liquid is forced out of the pores of a completely wetted PTFE bubble point membrane. The liquid used in the experiment must completely wet the membrane. At this time, in the membrane pores Will be filled with liquid.
When the gas pressure is greater than the capillary pressure and surface tension in the membrane pores, the liquid can be forced out of the membrane pores.
If the type of membrane is different from the wetting fluid, that is to say, changes in membrane material, membrane structure, pore size, surface tension, and temperature will all affect the bubble point pressure.
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