The rheology of some interfacial adsorbed films of macromolecules II. Stress relaxation phenomena

With the use of a surface rheometer especially designed for the purpose, stress-relaxation phenomena have been studied in unimolecular films of bovine serum album in, pepsin, poly-a, L-lysine (d.p. 15) and sodium arabinate at the hydrocarbon/water interface. The behaviour of the films has been analyzed in terms of the constituent rheological elements and the relaxation spectra have been obtained. From the dependence of the relaxation spectra on temperature, the activation energies for the relaxation of the films have been found. The relationship of these energies to the hydrogen bond energy (which, it was shown in part I, is largely responsible for the observed visco-elasticity) has been discussed.