Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Road, Taipei, 10607, Taiwan, Republic of China.
Nanoscale. 2018 Jan 18;10(3):1366-1375. doi: 10.1039/c7nr07360g.
The concurrent attachment and detachment movements of geckos on virtually any type of surface via their foot pads have inspired us to develop a thermal device with numerous arrangements of a multi-layer thin film together with electrodes that can help modify the temperature of the surface via application of a voltage. A sequential fabrication process was employed on a large-scale integration to generate well-defined contact hole arrays of photoresist for use as templates on the electrode-based device. The photoresist templates were then subjected to sputter deposition of the metallic glass ZrCuAlNi. Consequently, a metallic glass nanotube (MGNT) array having a nominal wall thickness of 100 nm was obtained after removal of the photoresist template. When a water droplet was placed on the MGNT array, close nanochambers of metallic glass were formed. By applying voltage, the surface was heated to increase the pressure inside the nanochambers; this generated an expanding force that raised the droplet; thus, the static water contact angle (SWCA) was increased. In contrast, a sucking force was generated during surface cooling, which decreased the SWCA. Our fabrication strategy exploits the MGNT array surface as nanosuckers, which can mimic the climbing aptitude of geckos as they attach to (>10 N m) and detach from (0.26 N m) surfaces at 0.5 and 3 V of applied voltage, respectively. Thus, the climbing aptitude of geckos can be mimicked by employing the processing strategy presented herein for the development of artificial foot pads.
壁虎几乎可以在任何类型的表面上通过其脚垫进行同时附着和脱离运动，这启发我们开发了一种具有多层薄膜和电极的热设备，通过施加电压可以帮助改变表面温度。我们采用了一种顺序制造工艺，在大规模集成电路上生成具有明确定义的光刻胶接触孔阵列，用作基于电极的器件的模板。然后，将光刻胶模板进行溅射沉积金属玻璃 ZrCuAlNi。因此，在去除光刻胶模板后，获得了具有标称壁厚度为 100nm 的金属玻璃纳米管 (MGNT) 阵列。当将水滴放置在 MGNT 阵列上时，形成了紧密的金属玻璃纳米腔。通过施加电压，表面被加热以增加纳米腔内部的压力；这产生了一个膨胀力，使液滴上升；因此，静态水接触角 (SWCA) 增加。相比之下，在表面冷却期间会产生吸力，从而降低 SWCA。我们的制造策略利用 MGNT 阵列表面作为纳米吸盘，当施加 0.5 和 3V 的电压时，纳米吸盘可以分别模拟壁虎附着 (>10 N m) 和脱离 (>10 N m) 表面的攀爬能力（0.26 N m）。因此，可以通过采用本文提出的处理策略来开发人工脚垫来模拟壁虎的攀爬能力。
