采用电化学氧化法,在泡沫铜多孔材料表面构建了纳米针结构.利用扫描电子显微、X射线衍射图谱分析及油水测试方法研究了电流密度对表面微观形貌、组成成分、润湿性和油水分离特性的影响.结果表明,增大电流密度可促进Cu(OH)2纳米针绒毛状微米团簇的生成,形成微纳复合结构,使超浸润性和油水分离特性明显提高.当电流密度为6 m A/cm2时,泡沫铜表面具有微纳复合结构.表面经改性后,水滴的静态接触角为161°,滚动角为7.2°,油滴则在表面完全润湿铺展,油水分离效率高达98%.同时,此改性表面显示出良好的抗水冲击性和耐水压性.
The leaf of lotus （Nelumbo nucifera） exhibits exceptional ability to maintain the opening status even under adverse weather conditions, but the mechanism behind this phenomenon is less investigated. In this paper, lotus leaves were investigated using environmental scanning electron microscopy in order to illustrate this mechanism. The macro-observations show that the primary veins are oriented symmetrically from leaf center and then develop into fractal distribution, with net-shaped arrangement of the side veins. Further micro-observations show that all the veins are composed of honeycomb micro-tubes viewed from cross section, the inner of micro-tubes are patterned with extended closed-hexagons from vertical section. Different positions of leaf possess diverse mechanical properties by size variation of diameter and inner hexagons of veins, which is theoretically analyzed by building a regular honeycomb model. Specifically, the central area of lotus tends to be stiffer while its margin be softer. These special distribution and composition of the veins mainly account for the distinct behavior of lotus.
