Thermo-mechanical and adhesive properties of polymeric films based on ZnAl-hydrotalcite composites for active wound dressings

Composite films based on sodium carboxymethyl cellulose (Na-CMC) loaded with a ZnAl(OH)2CO3yH2O hydrotalcite (ZnAl-HTlc), were developed and characterized. The composites were mechanically more stable than the matrix alone: the noticeable enhancement of elastic modulus, creep resistance and failure properties, all proportional to the filler content, came at the expenses of a certain embrittlement. The filler tended to aggregate in the composites and the size of the aggregates increased with ZnAl-HTlc amount. Contact angle measurements highlighted how ZnAl-HTlc introduction in the polymeric matrix could strongly modify the wettability conditions of the films increasing their hydrophilicity. Bioadhesion tests showed that the adhesion behavior of the composites decreased as ZnAl-HTlc amount increases, testifying the influence of the filler on the ability of the film to bind skin surface. Therefore, the developed films may find application as active wound dressings since ZnAl-HTlc can be easily intercalated with an active pharmaceutical ingredient to be progressively released on the wound.