The diffusion coefficient of chitosan (M = ∼100 kDa) in swollen hydrogen-bonded poly(ethylene oxide)/poly(acrylic acid) multilayer films was examined and determined to be 1.4*10 −12 cm 2/s. Using this technique, we explore issues common to the polyelectrolyte multilayer field, such as the competition between hydrogen bonding and electrostatic interactions in multilayers, blocking interlayer diffusion of polymers, the exchange of film components with a surrounding solution, and the extent and kinetics of interlayer diffusion. X-ray photoelectron spectroscopy paired with C 60 + cluster ion sputtering enables high-resolution analysis of the atomic composition and chemical state of organic thin films with depth. Interlayer diffusion of materials may destroy this precise structure therefore, a better understanding of when interlayer diffusion occurs and how to control it is needed. Functional organic thin films often demand precise control over the nanometer-level structure.
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