Department of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, P. R. China.
New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates.
Adv Mater. 2017 Oct;29(37). doi: 10.1002/adma.201702231. Epub 2017 Jul 31.
Materials that respond rapidly and reversibly to external stimuli currently stand among the top choices as actuators for real-world applications. Here, a series of programmable actuators fabricated as single- or bilayer elements is described that can reversibly respond to minute concentrations of acetone vapors. By using templates, microchannel structures are replicated onto the surface of two highly elastic polymers, polyvinylidene fluoride (PVDF) and polyvinyl alcohol, to induce chiral coiling upon exposure to acetone vapors. The vapomechanical coiling is reversible and can be conducted repeatedly over 100 times without apparent fatigue. If they are immersed in liquid acetone, the actuators are saturated with the solvent and temporarily lose their motility but regain their shape and activity within seconds after the solvent evaporates. The desorption of acetone from the PVDF layer is four times faster than its adsorption, and the actuator composed of a single PVDF layer maintains its ability to move over an acetone-soaked filter paper even after several days. The controllable and reproducible sensing capability of this smart material can be utilized for actuating dynamic elements in soft robotics.
材料对外界刺激能迅速且可逆地响应，目前是用作实际应用的致动器的首选材料之一。在这里，我们描述了一系列可编程致动器，它们可以作为单层或双层元件来制造，可对微量浓度的丙酮蒸气进行可逆响应。通过使用模板，将微通道结构复制到两种高弹性聚合物聚偏二氟乙烯（PVDF）和聚乙烯醇的表面上，使它们在暴露于丙酮蒸气时能发生手性螺旋。蒸气机械卷曲是可逆的，可以重复进行 100 多次而不会出现明显疲劳。如果将它们浸入液态丙酮中，致动器会被溶剂饱和而暂时失去运动能力，但溶剂蒸发后几秒钟内即可恢复形状和活性。丙酮从 PVDF 层的解吸速度比其吸附速度快四倍，由单层 PVDF 层组成的致动器即使在几天之后仍能保持在丙酮浸湿的滤纸上移动的能力。这种智能材料的可控且可重复的传感能力可用于驱动软机器人中的动态元件。
