A study of the permeability properties of surfactant modified poly(vinyl chloride) membranes

Poly(vinyl chloride) (PVC) membranes modified with the surfactants Tween 80, Triton X-100 and bis(2-ethylhexyl) hydrogenphosphate (BEP) have been developed which mimic the high permeability and selectivity properties of conventional dialysis membranes to a range of low molecular weight solutes. Surfactant loss from the membrane matrix (through physical leaching) was minimised when plasticising with BEP, a species which possessed extensive side-chain branching. The permeability of PVC plasticised with BEP, however, was uniquely shown to vary with the nature of the buffer and pH. A rationale is provided for these observations.