极性液膜马达的动力学机理和特征研究

Recent experiments showed that the suspended polar liquid films only driven by the crossed electric fields may exhibit some novel controlled electro-hydro-dynamical (EHD) flows (rotation or vibration). The corresponding device is called as "liquid film motor". Although they are of potential applicational importance in basic research and technology, their dynamical mechnisms are unknown, and the related theory and further detailed experiments are urgently required for explanations of the experimental phenomena and for ultimate verification of the theoretical predictions, respectively. In this project fundamental research on the dynamical mechanisms and properties of the polar liquid film motors is planned to be done by both theoretical models and experiments. The detailed contents are listed as follows: (1) the dynamical mechnism and properties of micro-scaled water film motor will be studied based on our previous theoretical work. (2) employing the electric quadrupole model we plan to investigate effects of molecules' spatial structures on the rotational modes of the liquid films to explain the related experimental phenomena. (3) experiments will be done to verify the theoretical predictions given in our paper published on [Microfluid Nanofluid 14, 319 (2013)] to further elucidate the rotational and vibrational mechanisms of the water film motor.Tranditional methods of mathematical physics and experimental validation are employed to develop the related theory for describing the dynamical properties of the polar liquid film motors.

最新实验表明悬浮极性液膜仅在交叉电场的驱动下就可以实现多种模式的可控电流体流动 (转动或振动)，相应实验设备被称为"液膜马达"。尽管它们在基础研究和工程应用方面具有广阔的应用前景，但是其动力学机理不详，尚有许多实验现象和理论预言亟待解释和验证。本项目拟从物理建模和实验验证两方面对液膜马达的动力学机理和特征进行基础研究，具体研究内容包括：(1)在原有理论研究的基础上探究微尺度水膜马达的动力学机制和特征，为实现其在微流控芯片中的潜在应用提供理论支持；(2)利用电多极矩模型研究分子的空间结构对液膜转动模式的影响，解释相关的实验现象；(3)实验验证我们发表在[Microfluid Nanofluid 14, 319 (2013)]中的若干理论预言，进一步阐明水膜马达的转动和振动机理。采用传统数学物理建模和实验验证相结合的研究方法着重发展描述极性液膜马达动力学性质的相关理论。

液膜马达的可控流动不仅为研究二维复杂流体的物理性质和极性液体的微观结构提供了很好的平台，也为其在微流控技术以及生物医学等领域中的潜在科技应用开拓了新思路。由于实验所涉及的领域较多，实验现象纷繁复杂，尽管人们对极性液膜马达在实验和理论方面都做了一些工作，但是人们对它们的动力学机制仍有争论，还有许多实验现象需要更合理的理论解释。本项目对极性液膜马达的动力学机理和特征进行基础性研究。(1)通过引入滑移边界条件，研究了界面效应对直流和交流极性液膜马达转动特征影响，分别给出极性液膜马达在负、无、部分和理想滑移条件下的随时空变化的转动特征；(2)针对电解质降低液膜马达和液膜发电机效率的实验事实，理论研究了电解质和尺寸效应对极性液膜马达动力学性质的影响，解析地给出了不同电导率和液膜马达装置尺寸下直流、交流和方波马达的时空演化规律；(3)综述了液膜马达和液膜发电机研究的最新进展，从理论上研究了极性分子形状对液膜马达动力学性质的影响，将分子划分成非、单、双和多偶极分子很好地解释了不同极性液膜的转动特征；我们从实验上验证了方波液膜马达的动力学特征，实验发现除了低频情况下液膜无法呈现对称性往复转动特征外，其它理论预言与实验符合得很好；(4)为了弄清楚液膜马达转动的微观机理，与国外学者合作研究了电磁场调制下超稀释极性溶液中相干畴的形成过程，分别给出了亲水性界面和强、弱和非电解质影响下形成相干畴的物理图像；(5)将自旋与极性分子的电偶极矩相类比，研究了低维自旋系统的磁性、热力学和动力学特征。本项目的研究将为液膜马达在微流控学中的应用提供有益的理论与实验参考。