Consider a spherically shaped molecule that has a molecular weight of 42 kDa through a microporous polycarbonate membrane. Assume that the molecule enters the pores of the membrane from a well-stirred bulk solution (i.e., there is polarization region) that is at 37oC (assume solvent is water). The membrane pores are cylindrical and have a diameter of 32 nm with an overall length of 325 micro meters. The membrane itself is 250 micro meters thick. The pores comprise 42% of the membrane volume (hint: this should not be confused with the porosity; you will need to find that). Determine (A) the solute molecule radius and its bulk diffusion coefficient, (B) the partition coefficient accounting for both steric exclusion and hindered diffusion (i.e., Kr), (C) the porosity and tortuosity of the membrane, and (D) the permeability of the membrane for the solute.

(Ans: =32.3%;Pm=3.55710-6cm/s)