Wetting of regularly structured gold surfaces
Wetting of regularly structured gold surfaces
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DOI：
10.1021/la047468q
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发表时间：
2005-03-01
期刊：
影响因子：
3.9
通讯作者：
Baumberg, J
中科院分区：
文献类型：
--
作者：
Abdelsalam, ME;Bartlett, PN;Baumberg, J
在这项研究中，我们报告了通过紧密堆积的均匀亚微米球体的单层模板对电沉积形成的结构金表面进行润湿的系统研究结果。在沉积后移除模板留下规则的六角形球形段孔阵列，其中孔的深度以及表面的形貌由通过模板沉积的金的厚度控制。我们发现，随着多孔膜厚度的增加，水在表面上的表观接触角从平面上的70度增加到130度以上，然后随着孔道半径以上厚度的增加，表观接触角又向70度方向减小。结果表明，尽管金本身是亲水性的，但表观接触角的这些变化与Cassie和Baxter在非湿表面的模型一致。我们还发现，在400-800 nm范围内，表观接触角与孔径无关。这是报道的第一个例子，表明亲水表面(小于或等于90度)变成疏水表面(θ(*)和90度)完全通过控制表面形貌。讨论了孔的形状和大小在稳定表面非湿润(Cassie-Baxter)液滴中的作用。
In this study we report results for a systematic study of the wetting of structured gold surfaces formed by electrodeposition through monolayer templates of close-packed uniform submicrometer spheres. Removal of the template after deposition leaves a regular hexagonal array of sphere segment pores where the depth of the pores and, thus, the topography of the surface are controlled by the thickness of gold deposited through the template. We find that, as the thickness of the porous film increases up to the radius of the pores, the apparent contact angle for water on the surface increases from 70degrees on the flat surface to more that 130degrees, and then with increasing thickness above the radius of the pores the apparent contact angle decreases back toward 70degrees. We show that these changes in the apparent contact angle agree with the model of Cassie and Baxter for nonwetted surfaces even though the gold itself is hydrophilic. We also show that the apparent contact angle is independent of the diameter of the pores over the range 400-800 nm. This is the first reported example showing the change of a hydrophilic surface (theta less than or equal to 90degrees) into a hydrophobic surface (theta(*) > 90degrees) purely by control of the surface topography. The role of the pore shape and size in stabilizing the nonwetting (Cassie-Baxter) droplet on the surface is discussed.