Photocatalytic performance and antimicrobial activities of HAp-TiO2 nanocomposite thin films by sol-gel method

Abstract

Hydroxyapatite/titanium dioxide composite thin films of different dipping cycle have been prepared by sol-gel processes. The morphology, chemical compositions and structures of the thin films were characterized by scanning electron microscope (SEM), Energy dispersive X-ray analysis (EDX). The crystalline phase and structure of the thin film nanocomposites were determined by XRD. The crystalline sizes of the composites were estimated in the range from 10nm to 25nm. The peak intensity of anatase phase increases with the increase of TiO2 concentration in the HAp/TiO2 composite there is no other impurity phases present in state. From the XRD peaks at 2θ= 31.724°, 31.706°, 31.731°, and 31.615° are the prominent characteristic peaks of HAp hexagonal phase. The addition of TiO2 clearly showed the development of rutile peaks at 2θ= 66.248°, 66.226°, 66.253°, and 66.146° which are the prominent characteristics peak of TiO2 rutile phases. The microstructural studies confirm that the HAp is embedded in the titania matrix. EDX analysis confirmed the presence of Ca, P, Ti and O respectively. The IR spectroscopy was performed on HAp/TiO2 thin films deposited on glass substrate. The stretching and vibrational properties of composites were reported the broad and medium peaks where observed at 440, 705cm−1 which also indicates the titania with rutile phase. The optical absorbance coefficient of a semiconductor close to the band edge can be expressed by the optical bandgap of HAp/TiO2 composite films of 4, 6 and 8 dipping cycle is 3.8eV, 4.0eV and 4.1eV respectively, from the literature the optical bandgap energy of HAp is 5.3eV and TiO2 is 3.2eV In our present study, significantly mid bandgap values have been observed. The antimicrobial activity test results showed that the composite films exhibited good inhibition on Gram positive and Gram negative bacteria.