The formation of polyelectrolyte complexation (PEC) films by dipping free-standing films of either gellan
gum (GG) or chitosan (CH) into solutions of opposite charge is reported. It was shown that the composition
and mechanical characteristics depend on pH, and the order in which the biopolymers were added, i.e.,
dipping CH into GG, or dipping GG into CH. Toughness, tensile strength, extensibility and density values
of PEC films prepared by immersing CH films into GG solutions increased with increasing CH:GG ratio.
This was not observed for PEC films prepared by dipping GG into CH. The observed behaviour is attributed
to the difference in their film compositions, i.e., films prepared by dipping GG into CH solution consist of
an inner CH layer and two outer GG layers. In contrast, GG appears to diffuse into the CH layer for films
prepared by dipping CH into GG.