Multilayer formation by a compressed monolayer of poly-epsilon-benzyloxycarbonyl-L-lysine

Molecular monolayers of poly-in-benzyloxycarbonyl-l-lysine were studied at the air/water interface. Deuterium-exchange measurements and the surface area of the monolayer are consistent with a structure consisting of condensed ordered arrays of alpha-helices. Collapsed films removed from the surface and air-dried were examined by polarized infrared spectroscopy and electron diffraction and found to consist of molecules in the alpha-helical conformation. There is no indication of a conformational change during compression of the monolayer, and a series of transitions found in the force-area curve are interpreted as the consecutive formation of additional layers of molecules. Some of the factors that influence this almost perfect plastic behaviour are discussed.