不同氧空位浓度的TiO_2纳米管阵列膜表面润湿特性研究

THE SURFACE WETTABILITY PROPERTIES OF TiO_2 NANOTUBE ARRAY FILMS WITH DIFFERENT OXYGEN VACANCY CONCENTRATION

采用阳极氧化法在钛基底上生长了Ti O2纳米管阵列膜,经不同温度、不同气氛中退火处理后,形成氧空位浓度不同的欠氧态Ti O2纳米管阵列膜。实验结果表明,随着退火温度的增加所有样品的接触角均逐渐减小,最后均呈现超亲水状态(接触角趋近于0°),但在氩气中退火处理的样品其接触角减小明显滞后于其他样品;再将这些样品在黑暗环境中放置100天后,发现其接触角均有所增大,并且仍是氩气中处理的样品接触角变化最大,达到疏水状态(接触角大于90°)。经模拟太阳光照射3 h后,这些样品表面又基本恢复到放置前的超亲水状态。重复上述实验发现这种润湿性转变是可逆的。深入的分析表征发现,不同气氛中退火处理的样品虽然表面形貌结构差异不大,但其结晶性和引入的氧空位浓度却有明显不同。因此,欠氧态Ti O2纳米管阵列膜的表面润湿性是由样品的结晶性和氧空位的浓度共同决定的,尤其氧空位的存在对其表面润湿性的影响须引起该领域研究者的重视。

The Ti O2 nanotube array films were prepared by anodization,then annealed at different temperatures under different atmospheres to obtain oxygen-deficient Ti O2 nanotube array films with different oxygen vacancy concentration.The experimental results showed that with the increase of the annealing temperature all the contact angles of the samples decreased gradually and present super hydrophilic state(contact angle very close to 0°),but the contact angle of the sample annealed in Argon gas decreased obviously lag behind.Deposing these samples in dark for 100 days,the contact angles of them all increased,and the biggest change was still from the sample annealed in Argon gas(contact angle greater than90°).After 3 h under illumination with the simulated sunlight,they all returned to the super hydrophilic.After repeated experiments it was found that the wettability switched was reversible.Further characterization analysis revealed that the morphologies of the samples were not much different after annealing treatment under various atmosphere,but their crystallinity and the oxygen vacancy concentration were obviously different.Therefore,the contact angle of the sample annealed under different atmosphere was both depended on its concentration of oxygen vacancy and its crystalline.Especially the surface wettability of samples related to oxygen vacancy should be paid more attention on this research field.