Environmental scanning electron microscopy images of the top surface and cross-sections of unmodified hydrogels (HA)0 (left column) and hydrogels with (PLL-HA)4-PLL, and (PLL-HA)9-PLL films (middle and right columns). The top surface of (HA)0 gel (left images) showed smooth surface whereas both (PLL-HA)4-PLL (middle images) and (PLL-HA)9-PLL (right images) showed rough granular/hair-like structure, (maginification 3000X). After multilayer formation, cross-section of hydrogel showed film formation (L) on the top layer in addition to the bottom layer of bulk hydrogel structure (H), (maginification 300X). In bottom row, the modified hydrogels showed diffusion of polyelectrolyte complexes inside the bulk of the hydrogels (marked with white arrow), (maginification 900X).