title: A new method for diffusion measurement in polymeric films based on a stacked sheet concept.
abstract: OBJECTIVE
  To develop and evaluate a simple, yet well defined, method to measure diffusion in semi-solids, i.e. polymeric materials.
  
  
  METHODS
  The method was based on a concept where equivalent discs of polymeric films were cut and stacked on top of each other. The diffusion process was allowed to proceed unidimensionally through the stack of films perpendicular to the film surface. After an appropriate time, the stack was analysed disc by disc with respect to solute content and from the concentration profile so obtained the diffusion coefficient was calculated.
  
  
  RESULTS
  An all-in-one device was developed, manufactured in stainless-steel, that cuts circular discs and stores each one successively in a "stack" in the cell compartment.
  
  
  CONCLUSIONS
  Data from a silicone based system shows that the method, although simple, is accurate and reproducible.
authors.affiliation: Department of Pharmaceutical Chemistry, Physical and Inorganic Chemistry, Uppsala University, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Sjöberg
authors.forename: R
authors.initials: R
authors.lastname: Bergman
authors.forename: L O
authors.initials: LO
authors.lastname: Sundelöf
mesh_terms: D004058:Diffusion; D004958:Estradiol / Q000737:chemistry; D015203:Reproducibility of Results; D012826:Silicone Elastomers / Q000737:chemistry*
chemical_list: D012826:Silicone Elastomers; D004958:Estradiol