INTERMOLECULAR INTERACTIONS IN NEWLY SPREAD SERUM ALBUMIN MONOLAYERS

Intermolecular interactions in newly spread serum albumin monolayers (at equilibrium spreading pressure) have been investigated using a modified Brookfield viscometer. Despite the high surface concentration, the intermolecular interactions develop at a relatively slow rate, but by complicated kinetics. The magnitudes of the drag and of the rate show that the interactions are affected by the spreading solvent, the age of the film, the degree of shearing motion in the monolayer, the ionic strength, and the presence of urea and certain ions. The two-dimensional network, which forms with monolayers of serum albumin and also with a surface-active extract from mammalian lung, may be of the type required to stabilize natural membranes. From a rheological point of view, a network on the surface may require the introduction of a plastic component to completely characterize the flow behavior of a monolayer. © 1969.