ИСТИНА

Nanogels formed as a result of aggregation of chitosan and hydrophobically modified (HM) chitosan macromolecules in dilute aqueous solutions were studied by light scattering and transmission electron microscopy (TEM). It was demonstrated that the size of nanogels and their aggregation numbers increase at the introduction of hydrophobic side groups into polymer chains. The key result concerns the effect of the chain length of individual macromolecules on the aggregation behavior. It was shown that both for unmodified and HM chitosan the size of nanogels is independent of the length of single chains, which may result from the electrostatic nature of the stabilization of their size. At the same time, the number of macromolecules in one nanogel increases significantly with decreasing length of single chains in order to provide a sufficient amount of associating groups to stabilize the nanogel. The analysis of the light scattering data together with TEM results suggests that the nanogels of chitosan and HM chitosan represent spherical particles with denser core and looser shell covered with dangling chains.