Zhang Xintong, Fujishima Akira, Jin Ming, Emeline Alexei V, Murakami Taketoshi
Kanagawa Academy of Science and Technology, Japan.
J Phys Chem B. 2006 Dec 21;110(50):25142-8. doi: 10.1021/jp064442u.
Dual function of self-cleaning and antireflection can be created in double-layered TiO2-SiO2 nanostructured films. The film were prepared by (1) layer-by-layer deposition of multilayered SiO2 nanoparticles with polydiallyldimethylammonium (PDDA) cations, (2) layer-by-layer deposition of multilayered titanate nanosheets with polications on PDDA/SiO2 multilayer films, and (3) burning out the polymer and converting titanate nanosheets into TiO2 by hearing at 500 degrees C. The as-prepared films, consisting of a porous SiO2 bottom layer and a dense TiO2 top layer, improved the transmittance of glass or quartz substrates, as demonstrated by transmission spectra collected at normal incidence. The photocatalytic properties of the films were studied by the change of the water contact angle together with the decay of the IR absorption of the hydrocarbon chain of octadecylphosphonic-acid-modified films under 2.6 mW cm-2 UV illumination. Both the antireflective and the photocatalytic properties of the films were dependent on the number of PDDA/nanosheet bilayers deposited. however, excellent surface wettability of the films for water was obtained, independent of the preparation conditions. The experimental findings are discussed in terms of the special structure of the double-layered nanostructured film.
双层TiO₂-SiO₂纳米结构薄膜可实现自清洁和抗反射的双重功能。这些薄膜通过以下步骤制备：（1）用聚二烯丙基二甲基氯化铵（PDDA）阳离子逐层沉积多层SiO₂纳米颗粒；（2）在PDDA/SiO₂多层膜上用聚阳离子逐层沉积多层钛酸盐纳米片；（3）在500℃下加热烧掉聚合物并将钛酸盐纳米片转化为TiO₂。所制备的薄膜由多孔SiO₂底层和致密TiO₂顶层组成，如在正入射下收集的透射光谱所示，提高了玻璃或石英基板的透过率。通过水接触角的变化以及在2.6 mW cm⁻²紫外光照射下十八烷基膦酸改性薄膜烃链红外吸收的衰减来研究薄膜的光催化性能。薄膜的抗反射和光催化性能均取决于沉积的PDDA/纳米片双层的数量。然而，无论制备条件如何，薄膜对水都具有优异的表面润湿性。根据双层纳米结构薄膜的特殊结构对实验结果进行了讨论。
