RF-Plasma deposition and surface characterization of stable (COOH)-Rich thin films from cyclic L-Lactide

Radiofrequency (13.56 MHz) glow discharges fed with vapors of (3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione (cyclic L-lactide) were used to deposit stable dense COOH groups. The L-lactide is the solid intermediate compound formed during the conventional polymerization reaction of poly lactic acid (PLA), a biodegradable polymer used in biomaterials. The coatings have been characterized by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and water contact angle (WCA) measurements. The percentage of surface carboxyl groups was determined by the Toluidine Blue O (TBO) test.