Control of surface texture of coating films prepared by the sol-gel method

本研究通过控制溶胶-凝胶法制备的涂层膜的表面织构来获得新的功能材料.沸水浸泡法在SiO_2-TiO_2凝胶膜表面生成了锐钛矿型纳米晶。沉淀膜具有较高的光催化活性。凝胶膜经60 ℃干燥后，在55 ℃的热水中浸泡也能形成锐钛矿晶体。在振动条件下，将薄膜浸入热水中，可以形成二氧化钛纳米片。二氧化钛纳米片的表面粗糙度小，具有超亲水性。即使在黑暗的地方保存超过2000小时后，这些性能也保持不变。用乙酰乙酸乙酯改性钛醇盐制备的SiO_2-TiO_2凝胶膜经紫外光照射后，其照射区域对各种溶剂的溶解度都变得很小。通过光掩模的紫外光照射和未照射区域的刻蚀，得到了SiO_2TiO_2凝胶薄膜的微图形。将微图案化的SiO_2-TiO_2凝胶膜浸入热水中，在微图案化的表面形成了纳米微晶.用乙酰乙酸乙酯改性醇铝制备的Al_2O_3凝胶膜在40 ℃的热水中浸泡，可形成20~50 nm的微小粗糙度。另一方面，具有小粗糙度的表面在宽波长区域显示出非常低的反射率。

In the present study, surface texture of the coating films prepared by the sol-gel method has been controlled to obtain new functional materials.1. Anatase nanocrystallites were found to be formed on the surface of SiO_2-TiO_2 gel films through immersion in boiling water. The anatase precipitated films showed high photocatalitic activity. Anatase crystals were formed even through the immersion of the gel films in hot water of 55 ℃ after being dried at 60 ℃. Titania nano-sheets were found to be formed through the immersion of the films in hot water under vibration. The surface with titania nano-sheets has a small roughness, and shows superhydrophilic properties. These properties were kept even after being kept under a dark place for more than 2000 h.2. When UV-light was irradiated on the SiO_2-TiO_2 gel films prepared from titanium alkoxide modified with ethyl acetoacetate, the solubility of irradiated area for various solvents become very small. By the irradiation of UV-light through a photo mask and etching of unirradiated area, micropatterns of SiO_2TiO_2 gel films were obtained. By immersion of the micropatterned SiO_2-TiO_2 gel films in hot water, anatase nano-crysltallites were formed on the micropatterned surface.3. Small roughness of about 20 to 50 nm was found to be formed by immersion of Al_2O_3 gel films prepared from Al-alkoxide modified with ethyl acetoacetate, in hot water at 40 ℃. On the other hand, the surface with the small roughness shows very low reflectivity with the wide wavelength region.