Sealing-free fast-response paraffin/nanoporous gold hybrid actuator
Sealing-free fast-response paraffin/nanoporous gold hybrid actuator
复制标题
免密封快速响应石蜡/纳米孔金混合执行器
DOI：
10.1088/1361-6528/aa7be6
复制
发表时间：
2017-09-20
期刊：
影响因子：
3.5
通讯作者：
Jin, Hai-Jun
中科院分区：
文献类型：
--
作者：
Ye, Xing-Long;Jin, Hai-Jun
基于石蜡的执行器可以提供大的驱动行程和高的驱动应力，但通常存在响应速度低和泄漏问题。在这里，我们报道了一种新型的石蜡/金属混合驱动器，它是通过石蜡渗透纳米多孔金而制成的。由于互连金属相的高热导率，它表现出快速的驱动速度，并且由于大的毛细作用，液体石蜡可以很好地限制在纳米尺度的通道中，因此不需要外部密封。我们发现，在这种混合驱动器中，当纳米多孔金(L)的特征尺寸在∼70 nm以上时，驱动产生的应力可以忽略不计，而当L和∼的特征尺寸小于70 nm时，驱动产生的应力随着尺寸的减小而急剧增加。L和lt；∼70 nm样品的高驱动应力归因于石蜡中的“小而强”效应--小孔中的石蜡可以承受更大的拉应力，因此冷却期间石蜡的收缩可以转化为金属骨架中更大的压应力和应变能，从而产生更大的驱动应力和能量。我们还证明，通过将分级结构的纳米多孔金属与石蜡结合起来，可以实现复杂的驱动运动。
Paraffin-based actuators can deliver large actuation strokes and high actuation stress, but often suffer from a low response rate and leaking problems. Here, we report a new paraffin/metal hybrid actuator, which was fabricated by infiltrating nanoporous gold with paraffin. It exhibits a fast actuation rate owing to the high thermal conductivity of the inter-connected metal phase, and requires no external sealing because liquid paraffin can be well confined in nanoscale channels, due to the large capillarity. We found that in this hybrid actuator, the stress generated by actuation is negligibly small when the characteristic size of the nanoporous gold (L) is above ∼70 nm, and increases dramatically with a decreasing size when L < ∼70 nm. The large actuation stress in samples with L < ∼70 nm is ascribed to a ‘smaller is stronger’ effect in paraffin wax—the paraffin in smaller pores can sustain larger tensile stress, and thus the contraction of paraffin during cooling can be translated into larger compression stress and strain energy in a metal framework, leading to a larger actuation stress and energy. We also demonstrate that complex actuation motions can be achieved by incorporating hierarchical-structured nanoporous metal with paraffin.