Townsend's method

Townsend's method is a way to measure the permeability of a membrane or filter by calculating how easily a substance passes through it. It involves passing a known concentration of a substance on one side and measuring the amount that appears on the other over time. The method uses the rate of transfer, the concentration difference, and the surface area of the membrane to determine its permeability. Essentially, it quantifies how accessible or resistant a barrier is to specific molecules, helping researchers understand and compare the efficiency of different membranes or filters in controlling substance flow.