Preparation,Growth Mechanism And Bioactivity Of Titania Nanorod Film With A High-Energy {101} Facets Preferred Orientation

Titanium and its alloys have been widely used as biomedical materials such as bone and dental implants due to their excellent mechanical properties and wonderful biocompatibility.However,titanium itself is inert material and cannot be directly bonded to bone.Thus,various surface modifications have been applied to the metal to enhance bone induction and conduction around the implants.Recently,the controllable titania film has been widely investigated during the past decades.Traditional rutile TiO₂ nanocrystals were dominated by the thermodynamically stable{110}facets other than the more reactive{101}facets.In recent years,researchers successfully synthesized the rutile titania film with a large percentage of reactive{101}facets on the anatase titania film,which was anticipated to have promising properties in solar cells.However,the bioactivity of rutile titania film with a large percentage of reactive{101}facets have not been investigated.The controllable synthesis,growth mechanism and bioactivity of TiO₂ film with a large percentage of rutile reactive{110}facets were investigated systematically in this thesis.Furthermore,the possible crystallographic match between TiO₂ and different exposed facets of apatite also was proposed.In this thesis,the titania nanorods film with dominant{101}facets of rutile were successfully prepared on the pure titanium by hydrothermal method at high pressure and their growth mechanism was investigated systematically by adjusting the titanium source.The XRD(X-ray diffraction)and SEM(scanning electron microscopy)indicated the vertical nanostructure were detected densely covering the whole surface of Tifoils and the morphology of the TiO₂ changed with the increasing of the concentration of titanium source,it changed from rod to needle shape,then to clusters.Moreover,the high-energy exposed(101)plane of rutile became oriented preferentially with the increasing of Tisource.The growth mechanism of titania nanorods film with dominant{101}facets of rutile on the Tifoil was discussed with assistance of titania nanorods film on the glass.The TEM(Transverse Electric and Magnetic Field)indicated the percentage of{110}facets of rutile in titania nanorod was change by adjusting the concentration of TiOSO₄,and the TiO₂ nanorod was only composed of rutile.The results showed that the phase transition and the morphology were strongly to crystal mechanism of TiO₂ nanostructures.The exposed(110)plane of rutile stimulated the growth of nanorod.And the exposed(101)plane of rutile was contributed for the formation of prongs of nanorod.The growth of exposed(110)plane of rutile nanorod film relied on 101-oriented anatase TiO₂ nanostructure film on the Tifoil.In this work,the titania nanorods film with with dominant{101}facets of rutile was obtained on the glass,when the glass and Tifoil were together loaded in mixture solution.The experiment results show that the size of nanorod on the glass was bigger than that on the Tifoils.The growth mechanism of nanorod formed on the Tiwas different from that on the glass.The bioactivity of titania nanorods film on the pure titanium was evaluated in SBF(simulated body fluid)for one day and three days.The experimental results indicated all samples can induced the deposition of apatite after soaked in SBF for one days,which means the excellent bioactivity of all the samples.Moreover,the size of apatite formed on titania nanorods film which was prepared in M₂(the volume ratio TiOSO₄and picric acid was 1)was smaller than other samples,which indicating the size of TiO₂ nanocrystals formed in M₂ was the smallest.It also illustrated that the TiO₂nanorods film have excellent specific surface area,which was contributed for the formation of apatite.The XRD results indicated that apatite was preferred to form on the exposed high-energy plane of rutile.Based on the data,the possible crystallographic match between TiO₂ and different exposed facets of apatite also was proposed.