Pdf low voltage electrowettingondielectric researchgate. Such electrically controlled wetting of a droplet, on a dielectric film, is classically. This study focuses on electrowetting using two immmiscible liquids on a dielectric coating. Ewod is a phenomenon where a voltage applied to a conducting liquid on a dielectric covered electrode causes. Continuous electrowetting in passivating and nonpassivating systems by mehdi khodayari a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy department of mechanical engineering college of engineering university of south florida comajor professor. This technique builds on the principle of electrowetting, which has proven useful in liquid actuation due to fast switching response times and low power consumption. Our present study aims to characterize and study droplet speed in a typical ewod device. On the other hand, multilayer dielectric has been known as a way to enhance the dielectric reliability by. Pcb manufactured electrowetting arrays impose many challenges due to the irregularities from process and materials used. Electrowetting on dielectric ewod digital microfluidics is a promising method of droplet manipulation that controls each droplet individually by an applying external electric field to the designated electrodes 1,2,3. Optimization of the electrowetting chips configuration to transport biofluid drops f. Volume and concentration identification by using an electrowetting on dielectric device yiyan li, hongzhong li, and r. In this device, a conducting droplet on the hydrophobic surface is manipulated by.
In this paper, the dielectric and electrowetting properties of pb zr0. Scaling electrowetting with printed circuit boards for. Volinsky department of mechanical engineering, university of south florida, tampa fl 33620, usa floating electrode electrowetting is caused by dc voltage applied to a liquid droplet on the cytop. Author links open overlay panel junghoon lee a hyejin moon b jesse fowler b thomas schoellhammer c changjin kim b.
October 2, 2002 the electrowetting phenomenon is investigated in the viewpoint of the. The state of the art includes already implemented technologies like ew displays or variable focus lenses but also laboratory level researches in. This article presents the characteristics of ewod device with aluminum oxide al2o3. Pdf volume and concentration identification by using an.
Electrowetting and electrowetting ondielectric for microscale liquid handling. It has the unique advantages of rapid response, low reagent consumption, and high integration and is mainly applied in the field of biochemical analysis. Electrowetting based devices flourished upon the discovery that an added dielectric layer between the drop and a conductive electrode would tolerate the application of. Droplet actuation by electrowettingondielectric ewod. Design and fabrication of an electrode for lowactuation. Design and fabrication of printed electrowettingon. An ewod device consists of a base substrate, a conducting electrode array, a dielectric layer, and a hydrophobic surface. Electrowettingondielectric ewod is a method that is used to manipulate microliter volumes of fluids in microfluidic devices. Improving the dielectric properties of an electrowetting.
Fp and wall materials is critical to the performance of the. Due to the expensive price of the fabrication process of the existing semiconductor technology, printing technology has become the center of much attention in research as a micro fabrication technology. We propose a simple theoretical model for the motion, which describes well the voltage dependency of droplet speed below the saturation voltage as measured experimentally. Accurate, consistent, and fast droplet splitting and. Using the setup shown in figure 1 with the counter electrode coated with dielectric teflonaf1600 on parylene, walter and fokkink applied a potential 0200v to acheive fast and reversible switching of the contact angle from 110 to 60 of aqueous droplets containing 104 m kno 3. How electrostatic fields change contact angle in electrowetting kwan hyoung kang department of mechanical engineering, pohang university of science and technology, san 31, hyojadong, pohang 790784, republic of korea received august 6, 2002.
This dependence of applied voltage on dielectric thickness is confirmed through ewod experiments for three different dielectric materials of. Electrowetting on dielectric experiments using graphene. Low voltage electrowettingondielectric article pdf available in journal of applied physics 927 october 2002 with 2,750 reads how we measure reads. Electrowetting on dielectric ewod properties of teflon. In these cases, liquid is in direct contact with air. The contact angle in response to the applied voltage is described by the. On the modelling of electrowetting in comsol multiphysics j. Multilayer insulator for low voltage and breakdown. Introduction electrowettingondielectric ewod is a new method for moving liquids in labonachip devices, such as biofluidic chips.
The interrogator from the carol burnett show full sketch duration. In this paper, we study the electrical properties and breakdown phenomena of pzt ferroelectric thin film in electrowetting systems. Preventing adsorption in electrowettingbased biofluidic chips 1. Proceedings of the asme 2012 third international conference on micronanoscale heat and mass transfer. This paper reports the electrowetting ew properties of silica layers. Electrowettingondielectric ewod allows us to control wettability of droplets on a solid surface using electrical inputs and has been used in a wide range of applications including microfluidics, optical displays, lenses, and others. Among printing technologies, the rreverseoffsetprinting rop method that can achieve high resolution and complicated shape patterns is utilized to fabricate the electrowettingon. In this project, a platform for the manipulation of droplets was developed and characterized. Electrowetting using an insulating layer on top of a bare electrode was later studied by bruno berge in 1993. Measurement of the thichkness of the cytop layer and estimation of the dielectric. Electrically modulated wetting of drops on soft dielectric films arxiv. The dynamic behavior of a droplet under various ewod conditions such as different applied frequencies and switching times is studied using highspeed imaging. First, a practical droplet speed measurement method has been methodically demonstrated and some related velocity terms have been introduced. The breakdown voltage depends on dc voltage polarity.
It was shown in1 through an analysis of a conducting drop. Droplet velocity in an electrowetting on dielectric. Volume 95, issues 23, 1 january 2002, pages 259268. Dielectric breakdown is a common problem in a digital microfluidic system, which limits its application in chemical or biomedical applications. Files are available under licenses specified on their description page. Low voltage electrowettingondielectric for microfluidic systems a dissertation presented to the faculty of the school of engineering and applied science university of virginia in partial fulfillment of the requirements for the degree doctor of philosophy by marcel mibus may, 2016. Improving the performance of electrowetting on dielectric micro. Supporting information for dc electrowetting of a nonaqueous liquid revisited by xps. Electrowetting on this dielectriccoated surface is called electrowettingondielectric ewod to distinguish it from the conventional electrowetting on the bare electrode. Lowcost silver screenprinted electrowetting on dielectrics. These challenges generally relate to preparing the surface that interfaces with droplets a dielectric material on the electrodes and the top most hydrophobic coating that interfaces with the droplets.
University of notre dame, notre dame, in, usa leslie. Volume and concentration identification by using an. Partially wetting liquid droplet at zero voltage dashed and at high voltage solid. Electrowetting on dielectric ewod is the control of contact angles wetting of droplets by applying an electrical voltage between the droplet and the counter electrode coated with a hydrophobic dielectric layer 11. Floating electrode electrowetting on hydrophobic dielectric with an sio 2 layer mehdi khodayari, benjamin hahne, nathan b. Wirelessly powered electrowettingondielectricewod d. Low applied voltage in electrowettingondielectric ewod can be achieved using thin dielectric. Droplet movement by electrowetting on dielectric ewod in a heleshaw cell is analysed theoretically and numerically. On the modelling of electrowetting in comsol multiphysics. Reducing voltage requirements for microfluidics fusayo saeki1, jean baum1, hyejin moon2, jeongyeol yoon3, changjin cj kim2 and robin l. For enabling this scheme, stacked deposition of thin dielectric and hydrophobic layer in that order between microchannel and electrodes is done. The fluids are set in motion using the electrowetting effect resulting in a pressure difference inside the tube. Electrowettingondielectric ewod based droplet actuation in microfluidic chip is designed and fabricated. Displays, electrowetting, electrowettingondielectric, lenses, microfluidics, younglippmann equation.
Nikapitiya 0 mun mun nahar 0 hyejin moon 0 0 mechanical and aerospace engineering department, the university of texas at arlington, arlington, tx 76019, usa this letter reports two novel electrode design. Micro and nano syst lett accurate, consistent, and fast droplet splitting and dispensing in electrowetting on dielectric digital microfluidics n. At the moment the droplet is actuated, the electrowetting force is balanced with the sum of all drag forces. Bindiganavale, govindraj shreyas, moon, hyejin, you, seung mun, and amaya, miguel.
We study the fluid dynamics of polar highk fluids immersed in nonpolar insulating fluids, excited by electrowettingondielectric ewod forces inside a tube with pressure compensation channels. E electrowetting 601 electrowetting, figure 1 schematic illustration of the various electrode con. We propose a new fabrication of an electrowettingondielectric ewod device using si3n4 deposited by lowpressure chemical vapor deposition lpcvd as a dielectric layer. Dielectric breakdown and failure of ferroelectric films as.
Electrowetting can be demonstrated by replacing the metal. Electrowetting on this dielectric coated surface is called electrowetting ondielectric ewod to distinguish it from the conventional electrowetting on the bare electrode. Reverse electrowetting as a new approach to highpower. The authors reported good agreement with published experimental saturation. Low voltage electrowettingondielectric for microfluidic. The pzt thin film is formed by spincoating, pyrolysis and annealing.
In this paper, we will investigate two more types of electrocapillary principles and demonstrate feasibility for mems. Preventing biomolecular adsorption in electrowettingbased. These constrains lead to the widespread use of hydrophobic fluoropolymers as the single dielectric layer. The motion of a conductive liquid on a dielectriccoated conductive substrate has been extensively studied in the past as a part of electrowettingondielectric. Using ferroelectric thin film as the dielectric for. Low voltage electrowettingondielectric platform using. Crane mechanical engineering department, university of south florida abstract electrowetting on dielectric is demonstrated with a thin spincoated fluoropolymer over an aluminum electrode.
In many electrowetting on dielectric ewod based microfluidics devices, droplet actuation speed is a crucial performancecontrolling parameter. This is the concept that has also become known as electrowetting on dielectric ewod. Since creating discrete droplets and pumping of liquids are done by surface tension alone, ewod digital microfluidics does not require intricate systems such as channels, pumps. The presented lowcost ewod stack consists of a suitable substrate, actuation electrodes and dielectrichydrophobic layers. In ewod, a droplet of liquid rests on a surface or in a. Electrowetting ew and electrowettingondielectric ewod can be used to handle aqueous liquid in microscale without any second liquid medium. Preventing biomolecular adsorption in electrowettingbased biofluidic chips. Ewod is used as onchip micropumping scheme for moving fluid digitally in labonachip devices. However it is followed by high possibility of dielectric failure. Where traditional electrowetting runs into challenges, however, such as in the simultaneous manipulation of multiple droplets. Electrowetting on dielectric ewod is useful in manipulating droplets for digital dropletbased microfluidics, but its high driving voltage over several tens of volts has been a barrier to overcome. All structured data from the file and property namespaces is available under the creative commons cc0 license. It is demonstrated that low contact angle of oil on the hydrophobic surfaces is a key parameter to.
The experimental results indicate that irreversible charge trapping occurred with repeated voltage actuation, resulting in contact angle relaxation and reduction of the ferroelectric film breakdown strength. Volume and concentration identification by using an electrowetting on dielectric device conference paper pdf available october 2014 with 160 reads how we measure reads. Optimization of the electrowetting chips configuration to. Digital microfluidic device for hotspot cooling in ics. We show that by decreasing the thickness and roughness of the dielectric layer and by increasing its dielectric constant, the threshold voltage for ewod can be. This material exhibits a greater relative permittivity, purity, uniformity, and. Digital microfluidic device for hotspot cooling in ics using electrowetting on dielectric. This article discusses and experimentally verifies how to lower the operating voltage that drives liquid droplets by the principle of electrowetting on dielectric ewod. A material system for reliable low voltage anodic electrowetting m. Volinsky department of mechanical engineering, university of south florida, tampa, florida 33620, usa. Fluid dynamics of an electrowettingondielectrics tube.
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