High Surface Area Reverse Electrowetting Mechanoelectrical Transduction

自供电传感器能够在几天到几周的时间内进行零维护监测和数据收集，目前对于许多不能定期使用太阳能或无线传输的应用来说是不可用的。这个研究项目的目标是利用一种基于液体的能量收集概念的高表面积优势，即反向电润湿，从低频运动中收集能量，并开发一种自供电运动传感器，以检测各种运动，如走路和跑步。小型化集成电路（IC）芯片也将被开发，这将使能量采集器非常适合其他工业和生物医学应用。这项技术将使开发能够长期运动传感的自供电设备成为可能，这种设备可用于监测从关节置换手术等手术中恢复的老年术后患者。自供电运动传感器将依靠收集的运动作为其外部能量来源，并将能够长期运行。这种无线传感器以前还没有被证明用于低频动能收集。此外，作为该项目的一部分，能源收集和电路设计经验将被添加到北德克萨斯大学（UNT）工程学院面向K-12青年的夏令营中，并为本科高级设计团队提供赞助。高表面积反电润湿依赖于在施加压力或电场的多孔电极内的可逆电解质运动。之前没有通过实验验证的关键限制参数包括电极孔径、电解质电导率、介电类型或厚度、表面光洁度以及压力和电压幅度或频率。将对这些参数进行建模、优化和实验验证，以实现厘米尺寸换能器的最大可用能量或功率。假设是：通过使用高表面积材料和参数优化，反向电润湿能够在10 Hz振荡频率下产生1 mW/cm2。这些设计参数将用于选择和集成高多孔电极材料（例如烧结金属和厚纸）与电解质、驻极体和外壳组件，以在~5 cm3的封装中实现最大的低频能量收集。将开发集成电路（IC）将收集的能量转换成可用的恒定直流电源。该系统将在柔性PDMS基板上集成低功耗无线数据传输电路和小型化天线，用于开发自供电、兼容的运动传感器。这种可穿戴式传感器将是独一无二的，因为它将是自供电和低成本的，并将展示高表面积反向电润湿的能力，从低频运动中收集足够的能量，以完全自供电可穿戴式运动传感器。本研究的具体贡献包括：对高表面积反电润湿的基本理解，在灵活系统中演示反电润湿，可以从低至30 mV输入电压开始的高效整流器和DC-DC转换器拓扑，以及具有无线数据传输能力的集成自供电运动传感器。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Self-powered sensors capable of zero-maintenance monitoring and data collection over days to weeks are currently not available for many applications that do not have regular access to solar energy or wireless power transmission. The goal of this research project is to use the high surface area advantage of a liquid-based energy harvesting concept called reverse electrowetting to harvest energy from low-frequency movement and to develop a self-powered motion sensor to detect various movements such as walking and running. A miniaturized integrated circuit (IC) chip will also be developed that will make the energy harvester highly suitable for other industrial and biomedical applications. This technology will make it possible to develop self-powered devices capable of long-term motion sensing that can be useful for monitoring post-operative elderly patients who are recovering from procedures such as joint replacement surgery. The self-powered motion sensor will rely on the harvested kinetic motion as its external energy source and will be capable of long-term operation. Such a wireless sensor has not previously been demonstrated for low-frequency kinetic energy harvesting. Also, as a part of this project, energy harvesting, and circuit design experiences will be added to the University of North Texas (UNT) College of Engineering summer camp for the K-12 youth as well as providing sponsorship for an undergraduate senior design team.High surface area reverse electrowetting depends on reversible electrolyte movement within a porous electrode with applied pressure or an electric field. Key limiting parameters that have not been previously verified experimentally include electrode pore size, electrolyte conductivity, dielectric type or thickness, surface finish, and the pressure and voltage magnitude or frequency. These parameters will be modeled, optimized, and experimentally validated to achieve the maximum available energy or power for a cm-sized transducer. The hypothesis is: reverse electrowetting is capable of producing 1 mW/cm2 at 10 Hz oscillation frequency through the use of high surface area materials and parameter optimization. These design parameters will be used in the selection and integration of highly porous electrode materials (e.g. sintered metal and buckypaper) with electrolyte, electret, and housing components for maximum low-frequency energy harvesting in a ~5 cm3 package. An integrated circuit (IC) will be developed to convert the harvested energy into a usable constant DC power supply. The system will be integrated with a low-power wireless data transmission circuitry and miniaturized antenna on a flexible PDMS substrate for developing a self-powered, conformable motion sensor. This wearable sensor will be unique as it will be self-powered and low-cost and will demonstrate high surface area reverse electrowetting's ability to harvest enough energy from low-frequency motion to entirely self-power a wearable motion sensor. Specific contributions from this research include: fundamental understanding of high surface area reverse electrowetting, demonstration of reverse electrowetting in a flexible system, highly efficient rectifier and DC-DC converter topologies that can start with as low as 30 mV input voltages, and an integrated self-powered motion sensor with wireless data transmission capability.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.