Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003.
Proc Natl Acad Sci U S A. 2020 Apr 14;117(15):8360-8365. doi: 10.1073/pnas.1922045117. Epub 2020 Mar 27.
Natural and man-made robotic systems use the interfacial tension between two fluids to support dense objects on liquid surfaces. Here, we show that coacervate-encased droplets of an aqueous polymer solution can be hung from the surface of a less dense aqueous polymer solution using surface tension. The forces acting on and the shapes of the hanging droplets can be controlled. Sacs with homogeneous and heterogeneous surfaces are hung from the surface and, by capillary forces, form well-ordered arrays. Locomotion and rotation can be achieved by embedding magnetic microparticles within the assemblies. Direct contact of the droplet with air enables in situ manipulation and compartmentalized cascading chemical reactions with selective transport. Applications including functional microreactors, motors, and biomimetic robots are evident.
自然和人造机器人系统利用两种液体之间的界面张力将密集物体支撑在液体表面上。在这里，我们展示了通过表面张力可以将包含凝聚物的水聚合物溶液液滴悬挂在密度较低的水聚合物溶液的表面上。可以控制作用在悬挂液滴上的力和液滴的形状。将具有均匀和不均匀表面的囊从表面悬挂，并通过毛细作用力形成有序排列。通过在组件中嵌入磁性微颗粒，可以实现运动和旋转。液滴与空气的直接接触可以实现原位操作和具有选择性传输的分隔级联化学反应。包括功能微反应器、马达和仿生机器人在内的应用是显而易见的。
