Super-Hydrophobic Surface Enabled Microfluidic Energy Conversion

目前，可充电电池被广泛用于为电子设备供电。为了满足快速增长的便携式电子设备的数量和密度的需求，电池的使用正在显著增加。如此快速的增长导致了电池回收和更换方面的重大挑战，以及与电池制造和处置有关的环境问题。因此，开发一种环保的替代能源收集方法来有效地延长电池的使用寿命甚至更换电池变得越来越迫切。为了满足这一迫切需求，本研究项目正在研究一种新型的大功率高效微流控能量回收技术，将机械能转化为电能。所提出的方法几乎可以在任何有压差的情况下运行。提出的环保方法被设想为从人类运动中回收电力。人类力量无处不在，资源丰富，环境友好，不受气候和环境的影响。这类应用对于在战场上使用或紧急和执法人员以及平民为各种便携式电子设备供电而引起军方的高度兴趣。这项技术有可能转化为关键的社会和环境效益，例如由于减少电池的数量和容量而减少污染。PI与当地高中合作，开发了一个已经很成功的夏令营。该项目的结果将用于一个夏令营的教育模块，该夏令营旨在吸引拉斯维加斯内华达大学的高中生学习工程学，该大学拥有大量拉丁裔人口。该项目探索了超疏水表面在能量转换方面的应用。采用理论和实验相结合的方法，该项目的中心目标是：(1)从根本上了解超疏水表面上的电动力学，以及(2)探索这些现象，以便利用超疏水表面设计新的高效、高功率密度的微流控能量转换装置。这项拟议的技术利用了一项发现，与传统的光滑表面相比，超疏水表面上的转换效率和功率密度可以大大提高。然而，关于超疏水表面上的能量转换的研究报道很少。在这个项目中，采用了一个集理论、计算和实验于一体的程序，目的是弥合这一基础知识鸿沟。PI将采用考虑表面传导和浓差极化的数学模型。这些因素在以前的建模工作中被忽略了，但对于实际应用来说是必不可少的。此外，PI将测量超疏水表面上的功率密度，以直接测试理论。反过来，验证后的模型将指导实验设计以及工程设计的能量转换性能。所提出的理论和实验相结合的方法将使PI能够探索超疏水表面上各种物理现象(非均匀表面传导、浓差极化和相关的扩散-渗透流动)的丰富行为。对这些重要现象的理解必将促进电动力学的基础知识，并为合理设计超疏水表面使能系统奠定坚实的基础。在认识有了很大提高的情况下，PI还提出使用微流控大规模集成方法将数千个通道集成到一个微流控芯片中，以论证转换方法在为小型电子设备供电方面的可行性。

Currently, rechargeable batteries are widely used to power electronic devices. The use of batteries is increasing significantly to meet the demand of the rapidly growing number and density of portable electronic devices. Such rapid growth results in major challenges in recycling and replacement of batteries, and environmental concerns related both to manufacturing and disposal of batteries. Therefore, the development of an eco-friendly alternative energy harvesting method to effectively extend the lifetime of batteries or even replace them becomes increasingly urgent. To meet this urgent need, the research project is investigating a new high-power high-efficiency microfluidic energy scavenging technology to convert mechanical energy into electricity. The proposed method can operate virtually in any situation having a pressure difference. The proposed eco-friendly method is envisioned to recover electricity from human locomotion. Human power is ubiquitous and abundant, environmentally friendly and independent of climate and environment. Such applications are of high interest to military for the usage on the battlefield or emergency and law enforcement personnel as well as civilians to power a broad range of portable electronic devices. This technology has the potential of translating into critical social and environmental benefits, such as decreased pollution due to the reduction in the amount and capacity of batteries. In partnership with local high schools, the PI has developed an already successful summer camp. Results from the project will be used in educational modules for a camp used to attract high school students to engineering at the University of Nevada in Las Vegas, which has a large Latino population. This project explores the application of super-hydrophobic surfaces for energy conversion. Using a combined theoretical and experimental approach, the central goals of the project are to: (1) fundamentally understand electrokinetics over super-hydrophobic surfaces, and (2) explore these phenomena in order to design new microfluidic energy-conversion devices with high efficiency and high power density, using super-hydrophobic surfaces. This proposed technology capitalizes on the finding that conversion efficiency and power density over a super-hydrophobic surface can be greatly enhanced compared to a traditional smooth surface. However, very little work has been reported on energy conversion over super-hydrophobic surfaces. In this project, a program integrating theory, computation and experiment is employed with the aim of bridging this fundamental knowledge gap. The PI will employ a mathematical model accounting for surface conduction and concentration polarization. These factors have been neglected in previous modeling efforts but are essential for practical applications. In addition, the PI will measure the power density over super-hydrophobic surfaces to directly test theories. In turn, the validated model will guide the experimental design as well as engineer the performance of energy conversion. The proposed coordinated theoretical and experimental approach will allow the PI to explore the rich behavior of a variety of physical phenomena (non-uniform surface conduction, concentration polarization, and associated diffusio-osmotic flows) over super-hydrophobic surfaces. Understanding of these important phenomena will surely advance the fundamental knowledge in electrokinetics and lay a solid foundation for the rational design of super-hydrophobic-surface-enabled systems. Equipped with a much improved understanding, the PI also proposes to use the microfluidic large-scale integration method to integrate thousands of channels into a microfluidic chip to demonstrate the feasibility of the conversion method in powering small electronic devices.