【作者】 罗凯；

【导师】 周明勇； 袁理；

【作者基本信息】 中南大学 ， 机械（专业学位）， 2025， 硕士

【摘要】 声表面波颗粒操控技术具有非接触与无标记、高精度与高灵敏度等优点,适用于大部分颗粒的操控。目前,声表面波颗粒操控技术的研究主要集中在对生物颗粒的操控上,利用声表面波操控导电颗粒排列是一个新兴的研究内容,对于制备低渗流阈值的导电复合材料以及可穿戴设备的研究具有重要的意义。本文首先对声表面波操控导电颗粒排列机制展开了研究,然后搭建了声表面波颗粒操控实验平台,设计了导电颗粒排列实验,探索了微米银颗粒排列的工艺,制备了微米银颗粒/聚乙二醇二丙烯酸酯（微米银颗粒/PEGDA）导电薄膜,并对其柔性传感应用进行研究。本文的主要工作和创新成果如下:（1）建立了考虑电场影响的声表面波颗粒排列仿真模型,并对颗粒的轨迹与受力进行分析。介电泳力在液体域中的分布规律是越靠近压电基底越大,其方向指向压电基底的电势节点处。在仿真中距离压电基底25μm的银和石墨受到的介电泳力达到了10^-14 N,声压节点处声辐射力达到10^-15 N,反声压节点处声辐射力达到10^-13 N,因此在电势节点处,颗粒受到的介电泳力大于声辐射力,被聚集在此处;在反声压节点处,声辐射力大于介电泳力,颗粒被驱动至横向声压节点处。（2）提出了采用聚二甲基硅氧烷（PDMS）与金箔制备电场屏蔽薄膜的方法,基于制备的电场屏蔽薄膜,设计了屏蔽电场的声表面波操控导电颗粒的实验作为常规声表面波颗粒操控实验的对照,研究了介电泳力对导电颗粒排列的影响。结果表明声辐射力将颗粒聚集在声压节点,而介电泳力会将颗粒聚集在电势节点处,极化的颗粒相互吸引形成颗粒链。介电泳效应的存在会干扰导电颗粒在声辐射力作用下的排列,其中石墨颗粒的介电泳效应最为显著,基于此确定了用银颗粒作为导电薄膜的导电填料。（3）探究了输入功率、腔室高度以及光敏溶液固含量对于导电颗粒排列效果的影响。选择27 d Bm的输入功率以及200μm的腔室高度高效、均匀地排列导电颗粒。测量了薄膜的电导率和弯曲响应曲线,分析了薄膜的导电机理及弯曲响应机理,制备的薄膜最大电导率可达7692 S/m。基于制备的导电薄膜研究了其对手腕弯曲、手指按压的响应,展示了微米银颗粒/PEGDA薄膜在人体运动感知以及生理信号监测上的广泛应用前景。图68幅,表8个,参考文献72篇更多还原

【Abstract】 The surface acoustic wave（SAW）particle manipulation technology features non-contact,label-free,high precision and high sensitivity,and is applicable to most particles.Currently,research on SAW particle manipulation mainly focuses on biological particles.Manipulating conductive particles’arrangement with SAW is an emerging area,crucial for preparing conductive composites with low percolation thresholds and researching wearable devices.In this study,the mechanism of SAW for conductive particle arrangement was first explored.Then,an SAW particle manipulation experimental platform was built,and an experiment on conductive particle arrangement was designed.The process of arranging micron silver particles was investigated,and a Micro-Ag Particles/Poly（ethylene glycol）diacrylate（Micro-Ag Particles/PEGDA）conductive film was prepared,followed by its application research in flexible sensing.The main work and innovative achievements are as follows:（1）A simulation model of SAW particle arrangement considering the electric field’s influence was established,analyzing particles’trajectories and forces.The dielectrophoretic force in the liquid domain increases closer to the piezoelectric substrate,pointing to its potential nodes.In the simulation,at 25μm from the substrate,silver and graphite particles’dielectrophoretic forces reach 10^-14 N,the acoustic radiation force at the acoustic pressure node is 10^-15 N,and at the anti-acoustic pressure node is10^-13 N.Thus,at potential nodes,dielectrophoretic force exceeds acoustic radiation force,aggregating particles;at anti-acoustic pressure nodes,acoustic radiation force prevails,driving particles to lateral acoustic pressure nodes.（2）A method of preparing an electric field shielding film with Polydimethylsiloxane（PDMS）and gold foil was proposed.Based on it,an SAW manipulation experiment of conductive particles with the electric field shielded was designed as a control for the conventional one,studying the dielectrophoretic force’s impact on particle arrangement.Results show that acoustic radiation force aggregates particles at acoustic pressure nodes,while dielectrophoretic force does at potential nodes,and polarized particles attract to form chains.The dielectrophoretic effect interferes with particle arrangement under acoustic radiation force,especially significant for graphite particles,so silver particles were chosen as the conductive filler for the film.（3）The effects of input power,chamber height,and photosensitive solution’s solid content on conductive particle arrangement were explored.An input power of 27 d Bm and a chamber height of 200μm were selected for efficient and uniform particle arrangement.The film’s conductivity and bending response curve were measured,analyzing its conduction and bending response mechanisms.The prepared film’s maximum conductivity can reach 7692 S/m.Its responses to wrist bending and finger pressing show the Micro-Ag Particles/PEGDA film’s broad application prospects in human motion sensing and physiological signal monitoring.更多还原