Analysis of linear macromolecule transport through aluminum anodic oxide membranes by pore model

An aluminum anodic oxide (AlAO) membrane consisting of highly regulated cyl indrical pores of 20-30 nm pore radius was prepared to clarify the applicab ility of two transport models, the original pore (OP) model and the steric- hindrance pore (SHP) model, to the structural characterization of ultrafilt ration (UF) membranes. Filtration and diffusion experiments were performed with the linear macromolecules dextran and polyethyleneglycol. The reflecti on coefficient (sigma) and solute permeability (P) were determined by analy zing rejection properties with the Spiegler-Kedem equation. In addition, th e value of P was measured by diffusion experiments. Comparing the observed values with the theoretical predictions makes it clear that membrane struct ure can be quantitatively evaluated with the OP model by characterizing the size of the macromolecular solute by its radius of gyration (r(g)), but no t by the Stokes-Einstein radius (r(s)).