Abstract:
The structure of the physical network of macromolecules on the surface of thin films obtained from aqueous solutions of gelatin during cooling from 320 to 273 K have been studied with a resolution of 6–8 nm in the scale range of 8–80 nm using electron microscopy. The analysis of density-density correlation functions has shown that with an increase in the magnitude of the scale, there are structural transitions from coils of macromolecules to fractal aggregates of coils, and then to a homogeneous physical network of particle entanglements. The depth of the intramolecular transformation coil-helix determines the degree of interpenetration of coils and thereby the width of the scale interval of structural transitions. The unfolding of the coils increases the correlation length and spatial uniformity of the polymer network structure.
Keywords:thin polymer films, electron microscopy, density-density correlations, network structure, tangles of macromolecules.