Macromolecular Chemistry I, Bavarian Polymer Institute (BPI) and Bayreuth Center for Colloids and Interfaces (BZKG) , University of Bayreuth , 95440 Bayreuth , Germany.
Institute of Physical Chemistry and Polymer Physics, Leibniz Institute of Polymer Research Dresden e. V. and Chair for Physical Chemistry of Polymeric Materials , Technical University Dresden , 01069 Dresden , Germany.
Langmuir. 2018 Nov 27;34(47):14249-14253. doi: 10.1021/acs.langmuir.8b03123. Epub 2018 Nov 14.
Controlled wrinkling is a rather simple method of fabricating surface topographies. The production process is based on the spontaneous formation of wrinkles upon compression of a hard film attached to a soft elastic substrate. Controlled wrinkling typically features large-scale wrinkled samples with a discrete wavelength and amplitude. In this report, we employ an approach utilizing linear metal layer thickness gradients for the controlled formation of gradient wrinkle patterns. The observed wavelength modulation was experimentally achieved by preparing layer thickness gradients of gold, chromium, and indium by physical vapor deposition in combination with a poly(dimethyl siloxane) elastomer substrate. In case of chromium and indium, a thin SiO surface layer was sufficient to ensure adhesion. However, in case of gold, an additional thin chromium adhesion layer was required. For the wrinkled gradient gold film, it was possible to tune the wavelength from 3.4 to 12.2 μm on a single substrate. The experimental data correspond well to the theoretical bilayer model from Stafford et al. Chromium has a significant higher Young's modulus and melting temperature than gold. However, chromium was successfully evaporated and gradient wrinkle patterns with wavelengths from 1.0 to 3.5 μm were realized. In contrast, indium has a considerable lower Young's modulus than gold and chromium, respectively. Consequently, lower wavelengths (0.6-1.0 μm) of the wrinkled gradient indium film were observed. These tunable wrinkled gradient metal films can be envisioned as components in sensors and optical and electro-optical devices.
可控褶皱是一种相当简单的制造表面形貌的方法。该生产工艺基于在硬膜与软弹性基底复合后受到压缩时，硬膜会自发形成褶皱。可控褶皱通常具有大尺寸的褶皱样品，具有离散的波长和振幅。在本报告中，我们采用了一种利用线性金属层厚度梯度来控制形成梯度褶皱图案的方法。通过物理气相沉积法在聚二甲基硅氧烷弹性体基底上制备金、铬和铟的层厚度梯度，实验实现了观察到的波长调制。对于铬和铟，只需一层薄的 SiO 2 表面层就能确保附着力。然而，对于金，则需要额外的薄铬附着层。对于褶皱的梯度金膜，可以在单个基底上从 3.4 到 12.2 μm 调节波长。实验数据与 Stafford 等人的双层模型理论很好地吻合。铬的杨氏模量和熔点明显高于金。然而，成功蒸发了铬并实现了具有 1.0 至 3.5 μm 波长的梯度褶皱图案。相比之下，铟的杨氏模量分别比金和铬低得多。因此，观察到褶皱梯度铟膜的较低波长（0.6-1.0 μm）。这些可调谐的褶皱梯度金属膜可以作为传感器以及光学和电光器件中的组件。
