Film formation and surface gelation of gelatin molecules at the water/air interface.

This publication presents new results on the formation of ultra-thin films of porcine gelatin molecules at the water/air surface. In a series of experiments we used the pendant-drop and vibrating-capacitor method for measuring dynamic surface tensions and electrostatic surface potentials. The surface shear and surface elongational rheological properties of the adsorbed layers of gelatin molecules were investigated by the torsion pendulum and the oscillating pendant-drop technique. The results of these experiments showed striking adsorption processes of the polypeptide molecules at the pure water surface even in the highly dilute concentration regime. These thin gelatin films exhibit striking viscoelastic properties, which correspond to two-dimensional gel states.