Barshilia Harish C, Chaudhary Archana, Kumar Praveen, Manikandanath Natarajan T
Surface Engineering Division, CSIR-National Aerospace Laboratories, Bangalore-560017, India.
Nanomaterials (Basel). 2012 Feb 29;2(1):65-78. doi: 10.3390/nano2010065.
The wettability of reactively sputtered Y₂O₃, thermally oxidized Y-Y₂O₃ and Cd-CdO template assisted Y₂O coatings has been studied. The wettability of as-deposited Y₂O coatings was determined by contact angle measurements. The water contact angles for reactively sputtered, thermally oxidized and template assisted Y₂O nanostructured coatings were 99°, 117° and 155°, respectively. The average surface roughness values of reactively sputtered, thermally oxidized and template assisted Y₂O coatings were determined by using atomic force microscopy and the corresponding values were 3, 11 and 180 nm, respectively. The low contact angle of the sputter deposited Y₂O₃ and thermally oxidized Y-Y₂O₃ coatings is attributed to a densely packed nano-grain like microstructure without any void space, leading to low surface roughness. A water droplet on such surfaces is mostly in contact with a solid surface relative to a void space, leading to a hydrophobic surface (low contact angle). Surface roughness is a crucial factor for the fabrication of a superhydrophobic surface. For Y₂O₃ coatings, the surface roughness was improved by depositing a thin film of Y₂O on the Cd-CdO template (average roughness = 178 nm), which resulted in a contact angle greater than 150°. The work of adhesion of water was very high for the reactively sputtered Y₂O₃ (54 mJ/m²) and thermally oxidized Y-Y₂O₃ coatings (43 mJ/m²) compared to the Cd-CdO template assisted Y₂O₃ coating (7 mJ/m²).
研究了反应溅射Y₂O₃、热氧化Y - Y₂O₃以及Cd - CdO模板辅助Y₂O涂层的润湿性。通过接触角测量确定了沉积态Y₂O涂层的润湿性。反应溅射、热氧化和模板辅助的Y₂O纳米结构涂层的水接触角分别为99°、117°和155°。利用原子力显微镜测定了反应溅射、热氧化和模板辅助Y₂O涂层的平均表面粗糙度值，相应值分别为3、11和180 nm。溅射沉积的Y₂O₃和热氧化的Y - Y₂O₃涂层的低接触角归因于致密堆积的纳米颗粒状微观结构，没有任何空隙，导致表面粗糙度较低。相对于空隙空间，水滴在这些表面上大多与固体表面接触，从而形成疏水表面（低接触角）。表面粗糙度是制备超疏水表面的关键因素。对于Y₂O₃涂层，通过在Cd - CdO模板上沉积Y₂O薄膜（平均粗糙度 = 178 nm）提高了表面粗糙度，这导致接触角大于150°。与Cd - CdO模板辅助的Y₂O₃涂层（7 mJ/m²）相比，反应溅射的Y₂O₃（54 mJ/m²）和热氧化的Y - Y₂O₃涂层（43 mJ/m²）的水粘附功非常高。
