Structural properties of different polypeptide multilayer nanofilms fabricated at neutral pH have been analyzed by UV spectroscopy, circular dichroism spectroscopy (CD), and Fourier-transform infrared spectroscopy (FTIR). The various peptides studied exhibit a strong tendency to adopt a beta sheet conformation in the films. Changes in film structure on dehydration are completely reversed on rewetting. The time scale of reversibility is, however, substantially shorter for the polymer backbone than the side chains, as in protein folding.