Permeation technique is used to study molecular aggregation in aqueous solutions including formation of cyclodextrin guest/host aggregates. Since only guest molecules, host molecules and guest/host aggregates that are smaller than the pore size of a given semipermeable membrane are able to permeate through the membrane, negative deviation of permeation profiles indicates formation of guest/host aggregates or self-aggregates. This chapter describes how the method is used to detect formation of nano-sized aggregates and to determine the critical aggregation concentration (cac) from permeation profiles of a guest molecule.
Keywords: Aggregates; Critical aggregation concentration (cac); Inclusion complexes; Permeation.