Note on an Equation of State for Linear Macromolecules in Monolayers *

I N recent years considerable interest has centered about the experimental study of monomolecular films of large molecules. The structure of cellulose and its derivatives,1 and of synthetic nigh polymers2-4 have been inves­ tigated by this technique. A greater number of papers have been published dealing with mono­ layers of protein molecules, in the determination of their size and structure5-7 and in the nature of their reactions. 8 In this paper we will present an equation of state for ma�romolecular mono­ layers derived on the basis of a highly idealized model, which should have significance for the films of synthetic polymers, but whose applica­ tion to those of proteins is rendered uncertain by the nature of the model. The investigations cited show that in true monomolecular films, polymer and protein mole­ cules alike lie flat and unfolded at the interphase. It is interesting thllt films of both polymers and proteins are highly compressible, and exhibit comparable force-area relations, though in three­ dimensional solution the protein is generally much more rigid and compact than the polymer molecule. However, while the latter might be