Chemistry and crystal growth of plant wax tubules of lotus (Nelumbo nucifera) and nasturtium (Tropaeolum majus) leaves on technical substrates
Chemistry and crystal growth of plant wax tubules of lotus (Nelumbo nucifera) and nasturtium (Tropaeolum majus) leaves on technical substrates
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DOI：
10.1021/cg060035w
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发表时间：
2006-11-01
影响因子：
3.8
通讯作者：
Barthlott, Wilhelm
中科院分区：
文献类型：
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作者：
Koch, Kerstin;Dommisse, Aarnoud;Barthlott, Wilhelm
由疏水和结晶微结构组成的蜡在大量植物上形成多功能表面。荷叶蜡提取物的扫描电镜（SEM）和化学分析和旱金莲属（Tropaeanummajus L.）表明这两个物种的蜡形成小管，并由脂肪族化合物的混合物组成，主要是壬醇和壬二醇。利用原子力显微镜（AFM）和扫描电子显微镜（SEM）研究了这些蜡管在技术表面上的重结晶。AFM研究提供了小管形成过程的连续图像，表明前体形态形成了一个圆形的基础，通过不断积累新的蜡分子形成小管。重结晶实验表明，蜡晶的形态与植物表面的蜡晶相似，但在不同基质上的微管取向和空间分布存在很大差异。在硅基底上，蜡优选形成厚的结壳，顶部具有随机取向的小管。在高度有序的热解石墨（HOPG）管主要垂直于基板生长在一个有序的空间分布。此外，在HOPG上，重结晶的蜡降低了基材的润湿性，对于莲花蜡约为40度，对于旱金莲蜡约为30度。
Waxes consisting of hydrophobic and crystalline microstructures form multifunctional surfaces on a great number of plants. Scanning electron microscopy (SEM) and chemical analysis of extracted leaf waxes of lotus (Nelumbo nucifera Gaertn.) and nasturtium (Tropaeolum majus L.) showed that waxes of both species form small tubules and are composed of a mixture of aliphatic compounds, principally nonacosanol and nonacosanediols. Atomic force microscopy (AFM) and SEM were used to study the recrystallization of these wax tubules on technical surfaces. AFM studies provided consecutive images of the tubule formation process showing that precursor morphologies form a circular basis, which form tubules by continuous accumulation of new wax molecules. Recrystallization experiments showed wax crystal morphologies similar to those on plant surfaces, but great differences were found in tubules orientation and spatial distribution on the different substrates used. On silicon substrates, waxes preferably formed thick crusts, with randomly orientated tubules on top. On highly ordered pyrolytic graphite (HOPG) tubules predominantly grew vertically to the substrate in an ordered spatial distribution. Furthermore, on HOPG the recrystallized waxes decreased the substrate wettability with approximately 40 degrees for lotus and 30 degrees for nasturtium waxes.