Compositional Dependence of Apatite Formation in Sol-Gel Derived Organic-Inorganic Hybrids1

摘要

In the present study,we report the bioactivity of PDMS-CaO-SiO_2-P_2O_5 hybrid materials prepared by a sol-gel method.The apatite formation on the surface of the specimen,after soaking in the simulated body fluid(SBF),was analyzed by thin-film X-ray diffraction(TF-XRD)and Fourier transform infrared(FT-IR)reflection spectroscopy.The structure and morphology of the surface layer were observed by FT-Raman spec-troscopy,BET,and scanning electron microscopy(SEM).It was found that the bioactivity increased with decreasing PDMS content and increasing CaO content.Also,an increase in P_2O_5 concentration from 0 to 3 mol % decreased the induction period for apatite formation.A further increase in P_2O_5 content,however,increased the induction period.It was also noted that an increase in the P_2O_5 concentration from 0 to 3 mol % increased the surface area and micropore area and volume and decreased the pore diameter.On the other hand,the opposite trends were observed with a further increase in the P_2O_5 concentration.Among the various ormosil samples prepared with different compositions,the highest bioactivity was obtained from the ormosil with the composition of 20 wt % PDMS [PDMS/(TEOS + PDMS)],15 mol % CaO [(Ca(NO_3)_2/TEOS)mole ratio],3 mol % P_2O_5 [TEP/TEOS mole ratio].