Xiong Guang, Elam Jeffrey W, Feng Hao, Han Catherine Y, Wang Hsien-Hau, Iton Lennox E, Curtiss Larry A, Pellin Michael J, Kung Mayfair, Kung Harold, Stair Peter C
Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
J Phys Chem B. 2005 Jul 28;109(29):14059-63. doi: 10.1021/jp0503415.
Anodic aluminum oxide (AAO) membranes were characterized by UV Raman and FT-IR spectroscopies before and after coating the entire surface (including the interior pore walls) of the AAO membranes by atomic layer deposition (ALD). UV Raman reveals the presence of aluminum oxalate in bulk AAO, both before and after ALD coating with Al2O3, because of acid anion incorporation during the anodization process used to produce AAO membranes. The aluminum oxalate in AAO exhibits remarkable thermal stability, not totally decomposing in air until exposed to a temperature >900 degrees C. ALD was used to cover the surface of AAO with either Al2O3 or TiO2. Uncoated AAO have FT-IR spectra with two separate types of OH stretches that can be assigned to isolated OH groups and hydrogen-bonded surface OH groups, respectively. In contrast, AAO surfaces coated by ALD with Al2O3 display a single, broad band of hydrogen-bonded OH groups. AAO substrates coated with TiO2 show a more complicated behavior. UV Raman results show that very thin TiO2 coatings (1 nm) are not stable upon annealing to 500 degrees C. In contrast, thicker coatings can totally cover the contaminated alumina surface and are stable at temperatures in excess of 500 degrees C.
通过原子层沉积（ALD）在阳极氧化铝（AAO）膜的整个表面（包括内部孔壁）进行涂层前后，利用紫外拉曼光谱和傅里叶变换红外光谱（FT-IR）对AAO膜进行了表征。紫外拉曼光谱显示，在用Al2O3进行ALD涂层前后，块状AAO中均存在草酸铝，这是由于在用于制备AAO膜的阳极氧化过程中引入了酸阴离子。AAO中的草酸铝具有显著的热稳定性，在空气中直到暴露于温度>900摄氏度时才会完全分解。ALD用于用Al2O3或TiO2覆盖AAO的表面。未涂层的AAO具有FT-IR光谱，其中有两种不同类型的OH伸缩振动，分别可归因于孤立的OH基团和氢键表面OH基团。相比之下，用Al2O3进行ALD涂层的AAO表面显示出单一的、宽的氢键OH基团带。涂有TiO2的AAO基材表现出更复杂的行为。紫外拉曼光谱结果表明，非常薄的TiO2涂层（1nm）在退火至500摄氏度时不稳定。相比之下，较厚的涂层可以完全覆盖受污染的氧化铝表面，并且在超过500摄氏度的温度下是稳定的。
