Hydrolysis of PLA-like Plasma Polymer Films with Varying Degree of Crosslinking

Poly-lactide acid (PLA) based biodegradable films are of interest for packaging materials or bioapplications. Plasma-assisted vacuum evaporation technique uses oligomers released during thermal decomposition of source polymer as precursors for plasma polymerization. Conventionally prepared PLA with mw = 10000 g/mol was used as a source polymer. Films were prepared at various RF (13.56 MHz) plasma powers (0-20 W) in order to vary the amount of crosslinking in the film.Swelling and hydrolysis of films were monitored in real time using spectroscopic ellipsometry. The concentration profile of products of hydrolysis was measured by liquid-chromatography (LC-MS). FTIR, XPS and SEM analyses were used for monitoring of film composition and surface characterization. Molecular weights of source polymer and of the plasma polymer were determined by gel-permeation chromatography (GPC). Possibility to prepare PLA-like plasma polymer films with controlled degradability by hydrolysis was demonstrated