仿生超浸润性结构对绕流调控的研究及应用

Overflow is an important phenomenon in the dynamic interactions between fluid and solid surface. Overflow means that the inertial flow has the trend to stay along solid surface, when there has relative movement between inertial flow and solid edge. Accurate manipulation of overflow has played critical roles in liquid transportation, microfluidics, and agricultural irrigation. Conventional overflow controls are mainly restricted in surface curvature and flow velocity manipulation, making the process complicated. In this project, inspired by anti-overflow behavior of lotus leaf and overflow behavior of peristome surface, we will utilize surface microscaled structures and surface wettabilities to control liquid overflow behavior at solid edges. Microscaled surface structures and surface superwettabilities could be constructed through microfabrication methods, and utilized to control single liquid overflow behavior and multi-fluids selective overflow. Based on the stimuli-responsive behavior of the smart materials, we will fabricate smart materials and study the liquid overflow behavior on curved smart materials by external stimulus. This project will provide a new idea in designing of dynamic wettable manipulation surfaces.

在固、液动态相互作用中，“绕流”是一种很重要的现象。它是指当固体边缘和连续流体之间存在相对运动时，流体具有依附于固体表面运动的现象。对绕流的精确控制在液体输运、微流体和农业灌溉等领域具有重要的研究价值。传统的绕流调控手段主要局限在调节固体边缘的曲率和液体的流速上，操作过程十分复杂。本项目受荷叶边缘抑制绕流、猪笼草瓶口促进绕流的启发，将利用表面微观结构和表面特殊浸润性调控流体在固体边缘的绕流行为。采用微加工手段制备具有微纳米结构和超浸润性的表面，探究其对单一流体绕流的调控、对混合流体选择性绕流的调控。基于智能材料的应激响应性，研究在外场刺激时，弯曲的智能表面对绕流的响应性调控。为设计制备动态浸润性调控材料提供了一种新思路。

液体在弯曲表面或表面边缘处的绕流现象普遍存在于生产生活的各个方面。对于绕流的精确控制将有利于提高生活的便利性、提高生产的效率，具有重要的应用价值。申请人从猪笼草口沿处多曲率结构和水膜定向绕流的关系受到启发，利用光固化3D打印和光刻技术制备了具有跨尺度、多曲率结构的仿生开放微流体器件，用于跨微/宏观尺度上调控流体自发的定向输运和油水体系的自发定向分离与输运的研究，解决了传统油水膜分离技术中阻力大、通量低的问题；选择性的在曲率结构表面修饰特殊浸润性薄膜，首次实现了利用曲率结构的超浸润特性对高韦伯数流体运动方向的调控。研究成果推进了对动态浸润性的理解，同时有助于利用绕流来解决油水分离的问题。