Title: Photocontrol of Fluid Slugs in Liquid Crystal Polymer Microactuators

Author: Jiu-an Lv, Yuyun Liu, Jia Wei, Erqiang Chen, Lang Qin, Yanlei Yu*

Journal: Nature, 2016, 537, 179-184

Abstract:

The manipulation of small amounts of liquids has applications ranging from biomedical devices to liquid transfer. Direct light-driven manipulation of liquids, especially when triggered by light-induced capillary forces, is of particular interest because light can provide contactless spatial and temporal control. However, existing light-driven technologies suffer from an inherent limitation in that liquid motion is strongly resisted by the effect of contact-line pinning. Here we report a strategy to manipulate fluid slugs by photo-induced asymmetric deformation of tubular microactuators, which induces capillary forces for liquid propulsion. Microactuators with various shapes (straight, ‘Y’-shaped, serpentine and helical) are fabricated from a mechanically robust linear liquid crystal polymer. These microactuators are able to exert photocontrol of a wide diversity of liquids over a long distance with controllable velocity and direction, and hence to mix multiphase liquids, to combine liquids and even to make liquids run uphill. We anticipate that this photodeformable microactuator will find use in micro-reactors, in laboratory-on-a-chip settings and in micro-optomechanical systems.

论文链接：

https://www.nature.com/articles/nature19344?utm_source=other&utm_medium=other&utm_content=null&utm_campaign=

JRCN_1_DD01_CN_NatureRJ_article_paid_XMOL

PDF下载：Photocontrol of Fluid Slugs in Liquid Crystal Polymer Microactuators.pdf

操纵少量的液体进行反应和分析在科学研究和实际应用中极具价值。目前，由于可以从时间和空间两方面实现光的远程控制，直接通过光驱动的方法操纵液体受到广泛的关注。在这里，我们报道了一种由线性液晶聚合物(LLCP)制备的坚固管状微执行器（TMAs），它在470 nm光照射下，靠近光源的部分的横截面积增大，产生可控的毛细管力，从而液体会自行向较窄的末端推进。于是，具有各种形状(直形、Y形、蛇形和螺旋形)的TMAs可以利用这种光诱导的非对称形变产生的毛细管力推动液体。这些TMAs能够在很长一段距离内，以可控的速度和方向对多种液体进行光控制，从而混合多相液体甚至推动液体上坡。这种方法既不依赖于润湿性梯度，也不依赖于马兰戈尼效应。值得注意的是，我们制备的TMAs不仅可以推动较大极性范围的简单液体，也可以推动广泛应用于生物医学和化学工程的复杂液体。因此，它们在微系统技术和结构中具有相当大的应用潜力，并且无需任何附加组件的协助。