室温镓基液态金属心跳效应的仿生构筑与应用研究

Chemomechanical effects are known to initiate fluid oscillations in certain liquid metals, which is one of the main ways to realize liquid pump. However, they typically produce an irregular motion that is difficult to deactivate or control. Compared with high energy loss in mechanical pump, the design of non-mechanical liquid pump with non-moving parts, low power consumption, and adjustable control are very important for the new bionic application of the micro-fluid system. In this system, liquids are needed that respond strongly to external stimuli such as electric fields by switching properties including volume, viscosity, or surface tension. Based on the above, this project takes the room temperature gallium-based liquid metals and electrode as the research objects. Micro- and nanostructures on the surface of the electrode are constructed, and the adhesion of the electrode surface with liquid metals are studied before and after the deformation of the liquid metals. Whereafter, the regular and controllable liquid metal heartbeat is realized at room temperature. We explore the regulation mechanism of the liquid metal beating caused by the novel macroscopic shape of the electrode, establish a scientific model between the micro- and macrostructure of the electrode surface and the performance of the liquid metal heartbeat effect, and expound the working principle of the liquid metal pump. By revealing the controllable liquid metal heartbeat effect, this project provides theoretical guidance and gist for the design of a new type of pulsed non-mechanical liquid pump and expands the application of liquid metal in fields such as microfluidic control, artificial muscle and liquid robot.

化学机械效应促使液态金属引发振荡是实现液体泵的主要方式之一。然而，化学机械效应通常会造成液态金属的不规则运动，使其很难激活和控制。相对于高能量损失和易损耗的机械泵，设计无运动部件、低功耗、可调控的非机械液体泵对微流体系统在新兴仿生应用中至关重要。在这个体系中，用来驱动的液体，其自身属性包括体积、粘度或表面张力等能够对外部刺激作出强烈反应。基于此，本项目以室温镓基液态金属和电极为研究对象，在电极表面构筑微纳米多尺度结构，通过调节液态金属通电前后形变及其电极表面的粘附性，实现室温条件下的有规律、可控的液态金属心跳。探究新颖的电极宏观形状对液态金属跳动的调控机制，建立电极表面微观和宏观结构与心跳效应性能之间的科学模型，阐明该液态金属泵的工作原理。通过揭示可调控的液态金属心跳现象，为新型脉动式非机械液态泵的设计提供理论指导和依据，以期拓展液态金属在微流控、人造肌肉驱动以及液体机器人等领域的应用。

液态金属心跳现象由于其无运动部件、低功耗、可调控等特点在微流控、人造肌肉驱动以及液体机器人领域受到广泛的关注。本项目通过设计新颖的环形电极内壁结构和基底结构，操控液态金属液滴心跳现象以及振荡运动。（1）液态金属液滴在石墨环内壁V型结构电极内的心跳现象。环形电极内壁V型结构需要在特殊的位置高度才能引起心跳现象。不同因素对心跳频率的影响被逐个探究，如液滴的体积、电压、倾角和石墨环结构高度。并将心跳的状态分为规则跳动，不规则跳动和不跳动三个区域。更重要的是，找到了心跳时石墨环内壁V型结构高度的理论界限。（2）液态金属液滴实现了在锯齿基板上石墨环电极内部跳动。研究了影响液态金属心跳频率的物理机制以及在各种锯齿尺寸和方向下对镓铟合金液滴铺展区域的影响。锯齿结构提供不对称纹理，影响心脏跳动期间液态金属液滴的变形。可实现了2.7至4.8赫兹跳动频率的调控，与光滑表面上的频率相比，可调频率范围增加了100%。机理在于镓铟合金液滴在锯齿基底上的氧化铺展表明液滴渗透到锯齿结构的凹槽中。（3）通过设计非对称的锯齿基底并通过全新设计阵列电极操控液态金属振荡运动。通过改变基底结构将液态金属在水平面的移动速度提高了20%。此外，液态金属的反重力移动结果表明在光滑表面液态金属液滴的爬升角度为3度，而液态金属液滴在锯齿基底的最大爬升角度达到7.5度。操控液态金属液滴的移动-停止，运动方向，穿过狭小空间，推动物体移动。