Apressure of 3 atm was required to force water through an initially dry teflon membrane of uniform pore size. determine the pore size. (theta_water = 110 degree, gamma_water = 73mn/m)

Explanation:

As it is given that = 3 atm =

                r = 73 mN/m

            =

As it is known that free energy of a wetting liquid in a solid-liquid interface is lower than the solid-gas interface free energy.

As a result, there will be spontaneous filling of pores but we need a non-reactive gas under the pressure so that the liquid can be forced out of the pores.

The pressure difference will be represented as . Hence, work done by the gas to increase interface free energy is as follows.

where,   = incremental volume of gas in the pore

                   dS = incremental solid-gas interface area due to .

So,             =

Therefore, formula to calculate pore size is as follows.

                       D =

Putting the given values into the above formula as follows.

                        D =

                            =

                             =

Thus, we can conclude that pore size is .