Electrophoretic deposition of silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings

Silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings were prepared on titanium substrate by electrophoretic deposition in n-butanol and chloroform mixture. The effect of the concentration of poly(epsilon-caprolactone) in suspension on the morphology and the microstructure of coatings were investigated, furthermore, the thermal behavior and in vitro bioactivity were also investigated. The results show that the coarse and accidented silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings were obtained by electrophoretic deposition when the concentration of poly(epsilon-caprolactone) in suspension was 6-16 g/l. The adsorption of poly(epsilon-caprolactone) on the surface of Si-HA particles hinders the electrophoretic deposition of Si-HA. The shear-testing experiments indicated that the addition of poly(epsilon-caprolactone) in suspension is in favor of improving the bonding strength of the coatings. After immersion in simulated body fluid for 8 days, silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings have the ability to induce the bone-like apatite formation.