| 摘要: |
| 超疏水表面在防污减阻、油水分离、生物医用等领域应用广泛，在摩擦发电蓝色能源收集领域展现出新的应用前景， 但其大面积制造及结构形貌的精确调控仍充满挑战。提出光刻和模塑成形相结合的微纳多级表面的可控制造工艺，分别以光刻工艺制造的微米孔和 V 形孔阳极氧化铝纳米孔为微米尺度和纳米尺度模板，采用一步模塑成形工艺实现微纳多级表面的构建，并通过改变模板尺寸简易并精确调控微纳多级表面的形貌和结构尺寸。通过接触角测量仪分析发现，相比单级纳米表面和单级微米表面，构建的微纳多级表面疏水性能显著提升，并实现超疏水，静态接触角最高达 158°，滚动角仅为 2°。最后开展超疏水微纳多级表面在水能收集方面的应用研究，采用搭建的固?液摩擦纳米发电测试装置分析表面结构对摩擦电输出性能的影响。结果表明：相比平膜和单级微米表面，微纳多级表面由于摩擦面面积增加和疏水性能增强产生更加优异的电输出信号。当水流速度为 8 mL / s 时，微纳多级表面的输出电压峰值最高为 46 V，短路电流峰值最高为 6.3 μA。提出了一步模塑成形工艺，实现了超疏水微纳多级表面的大面积、可调控制造，基于微纳多级表面构建的固-液摩擦纳米发电机有望应用于水能收集、自驱动传感等领域。 |
| 关键词: 超疏水 微纳多级表面 摩擦纳米发电机 水能收集 |
| DOI：10.11933/j.issn.1007?9289.20220713001 |
| 分类号:TH117 |
| 基金项目:国家自然科学基金（51905423，52075437）；陕西省自然科学基础研究计划（2022JM-244）资助项目 |
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| Controllable Fabrication of Superhydrophobic Micro / nano Hierarchical Surface and Its Application for Energy Harvesting |
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GUO Meiling, XU Zhentao, WANG Cheng, YANG Zhenchao, YANG Mingshun, LI Yan
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School of Mechanical and Precision Instrument Engineering, Xi’ an University of Technology,Xi’ an 710048 , China
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| Abstract: |
| Superhydrophobic surfaces have been widely used in antifouling, drag reduction, oil-water separation, and biomedicine applications. New triboelectric nanogenerator(TENG) applications have recently emerged for harvesting blue energy. However, large-area and controllable fabrication of superhydrophobic surfaces remains challenging. When a superhydrophobic surface is used in a TENG, the effects of its structure and morphology on the triboelectric output remain unknown. Here, a large-area, controllable, and scalable fabrication strategy is developed to manufacture superhydrophobic micro / nano hierarchical surface, and its application in a water-solid contact TENG is reported. A one-step photolithography and molding process is proposed to fabricate a micro / nano hierarchical surface composed of micropillars and nanopillars. The micropillars were formed using a lithographic mask equipped with a microhole array, and the nanopillars duplicated the structure of a V-shaped anodic aluminum oxide(AAO) mold. The structure of the micro / nano hierarchical surface can be controlled accurately and conveniently by regulating the size of the lithographic mask and AAO mold. Using scanning electron microscopy(SEM) observation, a series of micro / nano hierarchical structures were successfully fabricated. The micropillars and nanopillars showed high accuracy and good consistency. Subsequently, the hydrophobicity of the micro / nano hierarchical surface was analyzed using a contact-angle measurement system. The results indicate that, compared with the single-level nano surface and the single-level micro surface, the micro / nano hierarchical surface exhibits superior hydrophobic properties and achieves superhydrophobicity. This is because the surface exhibits a Cassie-Baxter wetting state, and the constructed micro / nano hierarchical structures can inhibit water droplets from immersing into the gap and obtain superhydrophobic properties. For the micro / nano hierarchical surface, as the center distance of the micropillars increased, the contact area between the surface and the water droplet decreased; thus, the hydrophobic performance was further enhanced. Specifically, when the center distance of the lithographic mask was 28 μm, the fabricated micro / nano hierarchical surface showed a static contact angle of 158° and a sliding angle of 2°. Finally, the micro / nano hierarchical surface was applied for water energy harvesting. The effect of the surface structure on the output performance of the water-solid contact TENG was analyzed using a testing setup with water continuously dripping onto the surface. The results show that the constructed micro / nano hierarchical surface generates a more robust triboelectric output compared to the flat surface and the single-level microsurface. This outstanding output performance originated from the higher charge density caused by the larger friction surface and superhydrophobic properties. For the micro / nano hierarchical surface, as the center distance of the micropillars increased, the triboelectric output was further enhanced owing to the more hydrophobic structure. Specifically, at a flow rate of 8 mL / s, the output voltage and short-circuit current of the water-solid contact TENG based on the micro / nano hierarchical surface with a mask center distance of 28 μm are approximately 46 V and 6.3 μA, respectively. In addition, the effect of the flow rate on the output performance was studied. As the flow rate increased, the output peak value and output frequency increased, which was attributed to the sufficient friction and faster contact-separation process at high flow rates. Therefore, the proposed photolithography and molding process realizes the large-area and controllable superhydrophobic micro / nano hierarchical surface fabrication. Applying the micro / nano hierarchical surface in water-solid contact TENG demonstrates its suitable potential applications in water energy harvesting and self-powered sensor devices. |
| Key words: superhydrophobic micro / nano hierarchical surface triboelectric nanogenerator water energy harvesting |
