Abstract
1. The various surface moments of like polymers can be understood in the light of the models in Table I, which are designed by considering the orientation of C=O bond at the interface. 2. The flexibility of polymer film can be measured not only by surface pressure but also by the time for perfect spreading, the largest area from which the reliable surface moment can be obtained, or the number of atoms in the main chain of the statistical kinetic unit. 3. The effect of hydrolysis of a milan solution by sulphuric acid on its film was examined.