Surfaces with tunable liquid adhesion have aroused great attention in past years. However, it remains challenging to endow a surface with the capability of droplet recognition and transportation. Here, a bioinspired surface, termed as TMAS, is presented that is inspired by isotropic lotus leaves and anisotropic butterfly wings. The surface is prepared by simply growing a triangular micropillar array on the pre‐stretched thin poly(dimethylsiloxane) (PDMS) film. The regulation of mechanical stress in the PDMS film allows the fine tuning of structural parameters of the micropillar array reversibly, which results in the instantaneous, in situ switching between isotropic and various degrees of anisotropic droplet adhesions, and between strong adhesion and directional sliding of water droplets. TMAS can thus be used for robust droplet transportation and recognition of acids, bases, and their pH strengths. The results here could inspire the design of robust sensor techniques.

中文翻译：

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用于液滴识别和运输的仿生各向异性表面的可逆结构工程

具有可调液体粘附力的表面在过去几年引起了人们的极大关注。然而，赋予表面液滴识别和传输能力仍然具有挑战性。这里展示了一种被称为 TMAS 的仿生表面，其灵感来自于各向同性荷叶和各向异性蝴蝶翅膀。通过在预拉伸的聚二甲基硅氧烷（PDMS）薄膜上简单地生长三角形微柱阵列来制备表面。PDMS薄膜中机械应力的调节允许可逆地微调微柱阵列的结构参数，从而导致各向同性和不同程度的各向异性液滴粘附之间以及水的强粘附和定向滑动之间的瞬时原位切换飞沫。因此，TMAS 可用于稳定的液滴传输以及酸、碱及其 pH 强度的识别。这里的结果可以激发鲁棒传感器技术的设计。