The separation process is affected by a number of factors related to the membrane itself and the operation conditions. For latex membrane systems, factors such as feed concentration and feed temperature are found to affect pervaporation properties similarly to solvent-cast membrane systems. However, effects relating to polymer structure and latex particle morphology are more complicated for latex membrane systems. The separation performance depends upon the combined contribution of all the effects. It is shown that effects which make a latex membrane achieve a higher degree of film fusion, or make the polymer more rigid, will raise the membrane selectivity and decrease the permeation rate. A good latex membrane can be obtained by balancing all the effects pertaining to polymer, particle, and film structure and morphology.