Li Chuanzong, Jiao Yunlong, Lv Xiaodong, Wu Sizhu, Chen Chao, Zhang Yiyuan, Li Jiawen, Hu Yanlei, Wu Dong, Chu Jiaru
School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei 230009, China.
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China.
ACS Appl Mater Interfaces. 2020 Mar 18;12(11):13464-13472. doi: 10.1021/acsami.9b20223. Epub 2020 Mar 5.
Shape memory polymer (SMP) surfaces with tunable wettability have attracted extensive attention due to their widespread applications. However, there have been rare reports on in situ tuning wettability with SMP materials. In this paper, we reported a kind of distinct superhydrophobic SMP microconed surface on the silver nanowire (AgNW) film to achieve in situ reversible transition between pinned and roll-down states. The mechanism is taking advantage of the in situ heating functionality of the silver nanowire film by voltage, which provides the transition energy for SMP to achieve the fixation and recovery of temporary shape. It is noteworthy that the reversible transition could be repeated many times (>100 cycles), and we quantitatively investigate the shape memory ability of microcones with varied height and space under different applied voltages. These results show that the tilted microcones could recover its original upright state under a small voltage (4-11 V) in a short time, and the shortest recovery time is about 0.5 min under an applied voltage of ∼10 V. Finally, we utilize SMP microcone arrays with tunable wettability to realize lossless droplet transportation, and the tilted microconed surface also achieves liquid unidirectional transport due to its anisotropic water adhesion force. The robust microconed SMP surface with reversible morphology transitions will have far-ranging applications including droplet manipulation, reprogrammable fog harvesting, and so on.
具有可调润湿性的形状记忆聚合物（SMP）表面因其广泛的应用而受到广泛关注。然而，关于使用SMP材料原位调节润湿性的报道却很少。在本文中，我们报道了一种在银纳米线（AgNW）薄膜上独特的超疏水SMP微锥表面，以实现钉扎态和滚落态之间的原位可逆转变。其机制是利用银纳米线薄膜通过电压的原位加热功能，为SMP提供转变能量，以实现临时形状的固定和恢复。值得注意的是，这种可逆转变可以重复多次（>100次循环），并且我们定量研究了在不同施加电压下不同高度和间距的微锥的形状记忆能力。这些结果表明，倾斜的微锥在小电压（4 - 11 V）下能在短时间内恢复其原始直立状态，在约10 V的施加电压下最短恢复时间约为0.5分钟。最后，我们利用具有可调润湿性的SMP微锥阵列实现无损液滴传输，并且倾斜的微锥表面由于其各向异性的水附着力也实现了液体的单向传输。具有可逆形态转变的坚固微锥SMP表面将在包括液滴操纵、可重新编程的雾收集等方面有广泛的应用。
