Fabrication of Bioglass®/poly(ɛ-caprolactone) composite coatings obtained by co-electrophoretic deposition on stainless steel

ABSTRACT In this work two kinds of "soft coatings" were obtained by co-electrophoretic deposition technique (co-EPD). In all cases a bioglass was used as inorganic phase, and a commercial poly(ɛ-caprolactone), (PCLC), and an anionic synthesized PCL modified with maleic anhydride (PCLS) were used as organic phase. To ensure an adequate coating over the metallic substrate, deposition process variables (such as electric voltage and time) were optimized. Metal coated samples were analyzed by complementary characterization techniques (FTIR, DSC) to confirm the presence of both phases on the composite coatings. From SEM analysis, larger agglomerates were observed for the coatings obtained using commercial PCLC compared to those prepared from anionic modified PCLS, with a high degree of coating of the metallic substrate and absence of microcracks. Finally, by immersion tests in simulated body-fluid (SBF), the bioactivity of the coatings was evaluated. X-ray diffraction tests demonstrated the formation of a hydroxyapatite (HA) precipitate on the surface coatings, and by SEM-EDS microanalysis it was determined that HA present in PCLS coatings showed a Ca/P value ~ 1.78, which is close to stoichiometric values observed in bone tissues.