Department of Applied Physics, Aalto University former Helsinki University of Technology, PO Box 15100, FI-00076 Aalto, Espoo, Finland.
Proc Natl Acad Sci U S A. 2012 Jun 26;109(26):10210-3. doi: 10.1073/pnas.1204328109. Epub 2012 Jun 11.
Nature offers exciting examples for functional wetting properties based on superhydrophobicity, such as the self-cleaning surfaces on plant leaves and trapped air on immersed insect surfaces allowing underwater breathing. They inspire biomimetic approaches in science and technology. Superhydrophobicity relies on the Cassie wetting state where air is trapped within the surface topography. Pressure can trigger an irreversible transition from the Cassie state to the Wenzel state with no trapped air--this transition is usually detrimental for nonwetting functionality and is to be avoided. Here we present a new type of reversible, localized and instantaneous transition between two Cassie wetting states, enabled by two-level (dual-scale) topography of a superhydrophobic surface, that allows writing, erasing, rewriting and storing of optically displayed information in plastrons related to different length scales.
大自然提供了许多令人兴奋的功能润湿特性的例子，例如基于超疏水性的自清洁表面和浸没昆虫表面上的被困空气，从而实现水下呼吸。这些例子启发了科学和技术领域的仿生方法。超疏水性依赖于 Cassie 润湿状态，其中空气被困在表面形貌中。压力可以触发从 Cassie 状态到 Wenzel 状态的不可逆转变，其中没有被困空气——这种转变通常对非润湿功能有害，应避免。在这里，我们展示了一种新的可逆、局部和瞬时转变两种 Cassie 润湿状态的方法，这得益于超疏水性表面的两级（双尺度）形貌，该方法允许在与不同长度尺度相关的电晕中写入、擦除、重写和存储光学显示信息。
