Papers by Author: Zhi Xian Zhang

Abstract: Using nano-TiO₂ particles obtained by hydrolysis of titanium oxysulfate (TiOSO₄) as the precursor, and polystyrene (PS) spheres as the template, TiO₂ hollow spheres were successfully deposited on CPTi substrates through layer-by-layer self-assembly technology. After ultraviolet light (UV) irradiation, the TiO₂ coatings were soaked in simulated body fluid (SBF) to explore their bioactivities. The effects of UV irradiation time and UV irradiation media on the bioactivities of nano TiO₂ coatings were investigated. The results show that bone-like apatite can be formed on the surface of nano TiO₂ coating irradiated by UV, and this reveals that the irradiated coating has good bioactivity. The amount of apatite formed on the surface of the coating increases with the increase of UV irradiation time. UV-irradiated media also influence the bioactivity of the coating. The bioactivities of nano TiO₂ coatings irradiated in air and SBF are better than that in water.

Abstract: Nanometer TiO2 microcapsule has potential applications in biochemistry, drug Controlled Release, and catalyst. Meanwhile, Ultraviolet (UV) light-induced bioactivity of titanium substrates is attracting more and more attention nowadays. Composite thin films formed by Nano-TiO2 microcapsule prepared by a novel and versatile technique of layer-by-layer (L-b-L) deposition using the Nanometer latex particles of Polystyrene (PS) as the template together with TiO2 films synthesized at low temperature by the hydrolysis of titanium chloride (TiCl4) precursor was successfully deposited on the different titanium substrates after the template was removed. Thus great expectation was placed on whether UV radiation can enhance the bioactivity of the titanium substrates after the composite thin films being deposited on its surface. The apatite-forming ability was evaluated after the UV-irradiated implants being soaked in simulated body fluid (SBF) within different hours by Scanning electron microscopy (SEM), XRD. The vitro results indicated that UV radiation was favored to formation of apatite on titanium substrates. Besides, the effect of different UV- irradiation time on apatite-forming was different.

Abstract: The TiO2 nanopowder was prepared with TiOSO4 as raw material at low temperature by hydrolysis method, and microspheres coated polyethylene and TiO2 were then fabricated on titanium by layer-by-layer self-assembly technology. Using ultraviolet irradiation of titanium coating in distilled water for some time, titanium with enhanced bioactivity was achieved when immersed in simulated body fluid (SBF). The morphology, size and crystal shape before and after ultraviolet irradiation were characterized by scanning electron microcopy (SEM) and X-ray diffraction (XRD). UV irradiation of titanium results in the conversion of Ti4+ to Ti3+ and the generation of oxygen vacancies, which could react with the absorbed water to form basic Ti–OH groups. Compared with the coating non-UV irradiation, the UV-irradiated coatings do not present any obvious differences in morphology, surface roughness, grain size and phase component; however, they have more abundant basic Ti–OH groups thus the water contact angle decreases greatly so the surface become much more hydrophilic.