Controlled growth and investigations on the morphology and mechanical properties of hydroxyapatite/titania nanocomposite thin films

In this paper, the focus is on understanding the properties of nanocomposite hydroxyapatite (HAp)/titania (TiO2) thin films with respect to TiO2 concentration. HAp/TiO2 nanostructured composite thin films with different TiO2 concentrations were successfully fabricated by a simple sol-gel dip coating method. Highly stable HAp and TiO2 sols were prepared prior to the formation of nanocomposite thin films. The coatings were performed under controlled dipping and heat treatment processes. Phase pure HAP and TiO2 were well developed in the nanocomposite after the heat treatment and this was confirmed by XRD. The SEM and AFM analyses of HAp/TiO2 nanocomposite coatings show the variation in the morphology as a consequence different TiO2 concentration. This shows a reduction in the particle size to nanoscale due to the addition of TiO2. The mechanical strength of the coating also increased upon the addition of TiO2 as determined by nanoindentation. The composite thin films with 50 and 80 vol.% of TiO2 show good mechanical strength when compared to other concentrations of TiO2. (C) 2010 Elsevier Ltd. All rights reserved.