Electrically Adjustable, Super Adhesive Force of a Superhydrophobic Aligned MnO2 Nanotube Membrane Authors: Xiao-Dan Zhao, Hai-Ming Fan,* Jun Luo , Jun Ding , Xiang-Yang Liu,* Bing-Suo Zou and Yuan-Ping Feng
期刊:Adv. Funct. Mater. 2011, 21, 184–190
摘要:A superhydrophobic membrane of MnO 2 nanotube arrays on which a water droplet can be immobilized by application of a small DC bias, despite a large contact angle, is reported. For a 3 μ L water droplet, the measured adhesive force increases monotonically with increasing negative voltage, reaching a maximum of 130 μ N at 22 V, 25 times the original value. It follows that the nearly spherical water droplet can be controllably pinned on the substrate,even if the substrate is turned upside down. Moreover, the electrically adjustable adhesion is strongly polarity-dependent: only a fi ve-fold increase is found when a positive bias of 22 V is applied. This remarkable electrically-controlled adhesive property is ascribed to the change in contact geometry between the water droplet and MnO 2 nanotube array, on which water droplets exhibit the different continuities of three-phase contact line. As the modulation in this manner is in situ, fast, effi cient and environmentally-friendly, this kind of smart material with electrically adjustable adhesive properties has a wide variety of applications in biotechnology and in lab-on-chip devices.
背后的故事: 或许加一个这样的叙述会比较有意思,因为每一个工作背后通常都有有一长串故事,这些故事本身就是科研过程。眼下这个故事有点长。08年的时候,Dr. Luo 发现了一种水热途径可以合成MnO2纳米管阵列,这种纳米管具有四方形的截面可以近竖直排列在不同材料的基片上,于是发表了一篇JPCC (
J. Luo*, H. T. Zhu, H. M. Fan*, J. K.
Liang, G.H. Rao, J.B. Li, J.Y. Zhang, Z. M. Du, Z. X. Shen, “Synthesis of
single-crystal tetragonal α-MnO2 nanotubes”, J. Phys. Chem. C112,12594, 2008)。我一直感觉这个工作是非常出色的工作并有着很重要的影响,但遗憾的是这个工作当时并没有发表在更好的杂志上。所以,就在想,它还可以做些什么?一个月以后,有一天我去医院,在医院等候室看到一本杂志,这个杂志是报道学校在科研及其他方面的进展。恰好,上面有一篇化学系一位教授写的简报关于MnO2纳米线的亲疏水性质。后面就比较简单,我找到Xiao Dan同学开始测量它的亲疏水性质,xiaodan同学比较认真和专心。受到江一些论文的启发,我们当时就想可以通过外界的stimulus来调制其湿性质。事实上,我们尝试了光和电,其实他们都有效果。但是MnO2由于缺陷存在本身是一个相对好的导体,所以电学调制后期作为主要的研究方向。经过了一年多的努力,最后完成了这个工作。