作者：霍远樑1, 李朋伟1, 王超2, 王根伟3, 桑胜波1, 张文栋1, 冀健龙1,4
作者单位：1. 太原理工大学信息工程学院 微纳系统研究中心, 山西 太原 030024;
2. 中国科学院力学所 非线性力学国家重点实验室, 北京 100080;
3. 太原理工大学力学学院 山西省材料强度与结构冲击重点实验室, 山西 太原 030024;
4. 太原理工大学 高端煤矿机械装备协同创新中心, 山西 太原 030024
关键词：能量采集;分子动力学;润湿性;石墨烯
摘要：
为深入了解界面润湿性对流固摩擦能量输出的影响机制，该文利用石墨烯薄膜制作不同界面接触角的俘能结构并进行实验测试。此外，基于分子动力学理论建立Couette模型并进行仿真验证。研究发现，俘能结构输出的电压随着接触角的增大而增加，接触角为69.5的俘能结构对应输出的电压是0.95 mV，相比接触角为45时输出的0.57 mV增长67%；输出的电压极性与溶液流动的方向有关；而且电压幅值与溶液流动速度及浓度有关，与流动速度成非线性关系。结合模拟结果提出一种界面润湿性对流固摩擦能量输出效率的影响机制，结果表明：宏观接触角是表征界面对水分子的束缚力的参数，也是影响溶液在界面附近滑移速度的关键因素，溶液离子拖动电子移动速度受滑移速度影响，并将最终决定输出电压大小。
The influence of interface wettability on the energy output from flow-solid friction over graphene
HUO Yuanliang1, LI Pengwei1, WANG Chao2, WANG Genwei3, SANG Shengbo1, ZHANG Wendong1, JI Jianlong1,4
1. Micro-Nano System Research Center, College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. The State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China;
3. Shanxi Key Laboratory of Material Strength and Structural Impact, College of Mechanics, Taiyuan University of Technology, Taiyuan 030024, China;
4. Advanced Coal Mine Machinery and Equipment Collaborative Innovation Center of Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, China
Abstract: In order to explore the influencing mechanism between wettability of surface and energy output from flow-solid friction, energy harvesting structures with different contact angle were made with graphene film and tested. Besides, a Couette model was established on the basis of molecular dynamic(MD) method and a simulation was carried out. Experimental results illustrate that a larger contact angle would result in a larger output voltage of energy harvesting structure, and an increase from 45° to 69.5° amounts to a 67% increase in output voltage from 0.57 mV to 0.95 mV. The polarity of output voltage is closely related to the flow direction of fluid and the voltage amplitude fits to a non-linear relationship with the fluidic velocity. In addition, the concentration also influences the output voltage. An influencing mechanism between wettability of surface and energy output from flow-solid friction is put forward on the basis of the simulation results. Analysis demonstrates that macroscopic contact angle characterizing the binding forces between fluid and solid phases is a critical factor that affects the fluid's slippage near the surface. The ions' velocities of charging and discharging are determined by the slippage and it exerts great influences on the amplitude of output voltage.
Keywords: energy harvesting;molecular dynamics;wettability;graphene
2018, 44(5): 130-136 收稿日期: 2017-10-13;收到修改稿日期: 2017-12-15
基金项目: 国家863项目（2015AA042601）；国家自然科学基金重点支持项目（51705354，61474079，61471255）；山西省基础研究计划项目（2015021092）
作者简介: 霍远樑(1993-),男,山西晋中市人,硕士研究生,专业方向为流固耦合能量俘获。
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