Download fulltext pdf 3d electrowettingondielectric actuation article pdf available in sensors and actuators a physical 234 september 2015 with 457 reads. Characterization of dielectric films for electrowetting on dielectric systems by ajay rajgadkar a thesis submitted in partial fulfillment of the requirements for the degree of master of science in mechanical engineering department of mechanical engineering college of engineering university of south florida major professor. In this study, hydrophobic cytop with a nominal dielectric constant of 2. The simplest electrowetting situation, used widely in many ewoc and ewod setups, is the spreading of a droplet of conductive liquid on a solid in the presence of an ambient dielectric fluid. Accurate, consistent, and fast droplet splitting and. Continuous electrowetting in passivating and nonpassivating. On the other hand, direct electrowetting on an exposed electrode surface can be controlled at an extremely low voltage 1v,6 which has made it possible to design a. Such setting is termed electrowettingondielectric ewod 2, and has become increasingly important in diverse applications requiring active control of. The biofunctionalization technique involves a dry liftoff method with an easy to remove parylenec mas. Bifunctionintegrated dielectric nanolayers of fluoropolymers. Electrowetting on dielectric experiments using graphene. Ewod is used as onchip micropumping scheme for moving fluid digitally in labonachip devices.
Dielectric droplet actuation have been numerically studied using. The breakdown voltage depends on dc voltage polarity. 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. This paper presents the design and fabrication of an electrode for lowactuation voltage electrowettingondielectric ewod devices. Ew and electrowettingondielectric ewod principles applied to microfluidic devices. A lowcost and highresolution droplet position detector for. In these devices, the wetting properties of the liquid phases can be manipulated by applying an electric field.
Alamreducing electrowettingondielectric actuation voltage using a novel electrode shape and a multilayer. Wirelessly powered electrowettingondielectricewod d. Us9630183b2 electrowetting on dielectric using graphene. This affects ewod behavior differently, depending on the droplet potential polarity with respect to the wafer cathodic.
Biofunctionalization of electrowettingondielectric. In electrowetting the balance of forces at the contact point is modified by the application of a voltage between a conducting fluid and the solid surface. Biofunctionalization of electrowettingondielectric digital microfluidic chips for miniaturized cellbased applications daan witters, a nicolas vergauwe, a steven vermeir, a frederik ceyssens, b sandra liekens, c robert puers b and jeroen lammertyn a. Download pdf info publication number wo2016166944a1. A liquid droplet is disposed on the dielectric layer. The reliability of an automated microfluidic system depends on its self.
Microviscometer based on electrowetting on dielectric article pdf available in electrochimica acta 528. An electrowetting system with protection against dielectric breakdown is presented. Author links open overlay panel junghoon lee a hyejin moon b jesse fowler b thomas schoellhammer c changjin kim b. In this paper, we study the electrical properties and breakdown phenomena of pzt ferroelectric thin film in electrowetting systems. Linear and rotational microhydraulic actuators driven by. The contact angle in response to the applied voltage is described by the. The only study that used integrated cdc for electrowetting on dielectric device ewod just has one cdc to detect a single droplet actuation speed.
Pdf download onchip double emulsion droplet assembly using electrowettingondielectric ewod and dielectrophoresis dep, with w. Dec 15, 2015 in this project, a platform for the manipulation of droplets was developed and characterized. Electrowetting without external voltage using painton. Increased droplet coalescence using electrowetting on.
Electrowetting ew involves the application of an electric potential across a solidliquid sl interface, which modifies the wetting properties of that interface by reducing the sl surface energy and induces a contactangle change without altering either the bulk liquid or solid properties. Electrowetting facilitates the controlled deposition of gallium alloys on any substrate, specifically those relevant to radio. An electrowetting on dielectric ewod device and a method of controlling an ewod device download pdf info publication number wo2016166944a1. Numerical and experimental investigation of bubble. However, no fluoropolymer possesses the desirable properties of both hydrophobicity and dielectric strength.
Optimization of the dielectric layer for electrowetting on. 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. Spie 8987, oxidebased materials and devices v, 89871s 8 march 2014. Sep 19, 2018 the electrowetting dielectric on the electrodes was nm of plasmadeposited sio 2 topped by 80 nm of spunon fluoropolymer cytop. Sep 21, 2010 electrowetting on dielectric ewd is an actuator based on controlling charge at the interface of liquids and insulators over buried electrodes 1, 2. With the inspiration from electrowettingcontrolled droplets, the potential advantages of electrowetting for bubble dynamics are investigated experimentally and numerically. Partially wetting liquid droplet at zero voltage dashed and at high voltage solid. By applying an external voltage over a liquid and a dielectriccoated surface, one achieves a reduction of the macroscopic contact angles for increasing voltage. Transport mechanism by which droplets on electrowettingon. Electrowetting uses voltage to manipulate small volumes of fluid for applications including labonachip and optical devices. We have fabricated a fullyflexible, focustunable microlens array on a sheet and demonstrated its imaging capabilities.
Request pdf electrowetting and electrowettingondielectric for microscale liquid handling this paper deals with electrowetting ew and electrowettingondielectric ewod principles applied. Sep 18, 2002 this article discusses and experimentally verifies how to lower the operating voltage that drives liquid droplets by the principle of electrowetting on dielectric ewod. Request pdf electrowetting and electrowetting ondielectric for microscale liquid handling this paper deals with electrowetting ew and electrowetting ondielectric ewod principles applied. Fluoropolymers play an essential role in electrowetting ew systems. Electrowetting on dielectric has been demonstrated in various configurations with different materials, but the basic components of ewod are electrodes, a thin hydrophobic insulator, and an electrically conductive liquid. Electrowetting is an electromechanical phenomenon 1, in which a small droplet usually with a volume of nano to micro liters, placed on a hydrophobic dielectric layer or a surface with micro pillars 2, changes shape upon application of an electric field across the droplet dielectric. Ewod is used as on chip micropumping scheme for moving fluid digitally in lab on achip devices. Basics and applications of electrowetting on dielectric ew. Pdf electrowetting and electrowettingondielectric for. An electrowetting device and a method of electrowetting may be provided. In this project, a platform for the manipulation of droplets was developed and characterized.
A lowcost and highresolution droplet position detector. Ewod electrowetting on a dielectric is a microfluidic strategy that exploits surface tension as a means to manipulate liquid droplets at the current stage 48, 49. A numerical study of microfluidicdroplet motions in parallelplate electrowettingondielectric ewod devices by. This is the concept that has also become known as electrowetting on dielectric ewod. The system demonstrates virtually instantaneous selfhealing within 100 ms after dielectric breakdown under both dc and certain ac electrowetting conditions. We integrated fieldprogrammable gate array fpga as the address counter in our study. We find that the voltage at which the oil film ruptures is sensitive to the application of relatively low dc voltages prior to switching. Low voltage electrowettingondielectric platform using. Flexible electrowettingondielectric microlens array sheet. Electrowetting and electrowettingondielectric for microscale liquid handling. Electrowetting on this dielectric coated surface is called electrowetting on dielectric ewod to distinguish it from the conventional electrowetting on the bare electrode. For enabling this scheme, stacked deposition of thin dielectric and hydrophobic layer in that order between microchannel and electrodes is done. 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. Over the last decade, growing interest in ewod has led to a wide range of scientific and technological investigations motivated by its applicability in microfluidics, especially for dropletbased optical and labona.
To avoid electrochemical reactions, a dielectric often separates the fluid from the electrode, which has the undesired effect of adding processing steps while increasing the voltage necessary for electrowetting. In our experimental system, a 100 nanometer thin film gold metal was used as an electrode, and a 6. By applying an external voltage over a liquid and a dielectric coated surface, one achieves a reduction of the macroscopic contact angles for increasing voltage. An electrowetting on dielectric ewod device and a method of controlling an ewod device. Electrowettingondielectric ewod based droplet actuation in microfluidic chip is designed and fabricated. Latticeboltzmann simulations of electrowetting phenomena. Volume 95, issues 23, 1 january 2002, pages 259268. Pdf basics and applications of electrowetting on dielectric ew. Universal transient dynamics of electrowetting droplets. The reactions on the surface are independent of both the precursor gas quantity. We model the fluid dynamics by using heleshaw type equations with a focus on including the relevant boundary phenomena. Impedance spectroscopy and electrical modeling of electrowetting on dielectric devices view the table of contents for this issue, or go to the journal homepage for more. 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.
Jan 27, 2020 among them, the beam tuning system driven by electrowetting on dielectric ewod 8,9,10, which is defined as the change in the contact angle between an electrolyte and a dielectric surface owing. Dc current response during electrowetting on intentionally damaged. Electrowetting on dielectric ewod, as a tool to manipulate tiny amounts of liquids on a surface, has been widely used in microfluidic devices, including labonachip devices 14, adjustable lenses 5, 6, new electronic displays 7, 8 and optical fibers. Digital microfluidics technology based on the electrowettingondielectric ewod.
Jan 16, 2018 such setting is termed electrowetting on dielectric ewod 2, and has become increasingly important in diverse applications requiring active control of droplets such as fast response displays 3. Electrowetting is a commonly used tool to manipulate sessile drops on hydrophobic surfaces. Apr 25, 2019 electrowetting is a commonly used tool to manipulate sessile drops on hydrophobic surfaces. In many applications the solid surface consists of a thin dielectric deposited onto a conducting layer.
Electrowetting on dielectric 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. Ew and electrowettingondielectric ewod principles applied to microfluidic. Reducing voltage requirements for microfluidics fusayo saeki1, jean baum1, hyejin moon2, jeongyeol yoon3, changjin cj kim2 and robin l. Electrowetting using an insulating layer on top of a bare electrode was later studied by bruno berge in 1993. It comprises an electrolyte and a parylenec film deposited on an aluminum electrode. Adaptive optical beam steering and tuning system based on. Low voltage electrowettingondielectric platform using multi.
Design and fabrication of an electrode for lowactuationvoltage. Pdf low voltage electrowettingondielectric researchgate. Electrowetting is an electromechanical phenomenon 1, in which a small droplet usually with a volume of nano to micro liters, placed on a hydrophobic dielectric layer or a surface with micro pillars 2, changes shape upon application of an electric field across the dropletdielectric. Biofunctionalization of electrowetting ondielectric digital microfluidic chips for miniaturized cellbased applications. Electrowetting can be demonstrated by replacing the metal.
Electrowetting on dielectric devices uses a conducting water and. Ewd is believed to be the most feasible and efficient microfluidic actuator for lab on achip applications, as the droplets can be promptly driven to a precise position, which is not achievable. The electrostatic forces all play out near the contact line, on a scale of the order of the thickness of the solid dielectric layer. Electrowetting devices with an initial superhydrophobic water contact angle 150 have now been demonstrated on a variety of structured substrates. Dielectric layers, a few nm thick, are possible with atomic layer deposition ald. These substrates are more complex than a conventional superhydrophobic surface since electrowetting requires an electrical conductor that is coated with a highperformance dielectric and a. The authors reported good agreement with published experimental saturation. Droplet from stillness to motion needs to go through three processes. Modeling the fluid dynamics of electrowetting on dielectric. Oct 20, 2010 liquid droplet movement with electrowetting. There are two selflimiting surface reactions resulting in a monolayer per step. Dielectric breakdown and failure of ferroelectric films as.
This paper discusses the modeling and simulation of a parallelplate electrowetting on dielectric ewod device that moves fluid droplets through surface tension effects. Improvement of droplet speed and stability in electrowetting. In the fabricated system, the pcb is used as a substrate and is covered with plastic tape. 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. Ew and ewod are principles that can control wettability of liquids on solid surfaces using electric potential. The electrode has a graphene layer having a first side and a second side that opposes the first side. This article discusses and experimentally verifies how to lower the operating voltage that drives liquid droplets by the principle of electrowetting on dielectric ewod. Here, we investigate a problem in the operation of electrowetting on dielectric caused by a finite conductivity of the oil2. A significant contact angle change 12080 is desired to reliably pump the droplet in microchannels for applications such as labonachip or micrototal analysis systems. Among them, the beam tuning system driven by electrowetting on dielectric ewod 8,9,10, which is defined as the change in the contact angle between an electrolyte and a. The electrowetting dielectric on the electrodes was nm of plasmadeposited sio 2 topped by 80 nm of spunon fluoropolymer cytop. In this paper we report on the controlled biofunctionalization of the hydrophobic layer of electrowettingondielectric ewod based microfluidic chips with the aim to execute adherent cellbased assays. Figure 1 with the counter electrode coated with dielectric teflon. Ew and electrowetting ondielectric ewod principles applied to microfluidic devices.
Dielectric breakdown is investigated by observing the bubbles forming during electrowetting test caused by electrolysis. Af1600 on parylene, walter and fokkink applied a potential 0200v. Electrowetting and electrowetting ondielectric for microscale liquid handling. A dynamic electrowetting simulation using the levelset.
Floating electrode electrowetting on hydrophobic dielectric. Biofunctionalization of electrowettingondielectric digital. Request pdf on jan 1, 2012, melanie auffan and others published electrowetting ondielectric ewod find, read and cite all the research you need on researchgate. Electrowetting on dielectric devices uses a conducting water and insulating oil liquid phase in conjunction on a dielectric layer. Wo2016166944a1 an electrowetting on dielectric ewod. Before assembly, photoresist was stripped with acetone and methanol, and the. Digital microfluidic dynamic culture of mammalian embryos.
Pdf microviscometer based on electrowetting on dielectric. Numerical modeling of 3d electrowetting droplet actuation. Each liquid lens of the array is individually tunable via electrowetting on dielectric ewod actuation and is situated on a polydimethylsiloxane pdms substrate, which allows the lens array to operate as a reconfigurable optical system. Pcb printed circuit board substrate electrowetting devices are low cost and quickly fabricated, and they can be placed easily with digital controlling systems.
Electrowetting on gold electrodes with microscopic three. 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. Droplet actuation by electrowettingondielectric ewod. Electrowetting on dielectric ewod based droplet actuation in microfluidic chip is designed and fabricated. The electric field can rupture the initially flat oil film and promotes further dewetting of the oil. Ald is a technique for deposition of thin layers by chemical reaction of gaseous starting materials, the socalled precursors, with the substrate. A low voltage, twolevelmetal, and multilayer insulator electrowettingondielectric ewd platform is presented. Electrowetting on dielectric ewod on a digital microfluidic. The electrode also has a dielectric layer disposed on the first side of the graphene layer. In this study, for the first time, we report the integration of two representative fluoropolymersnamely, teflon af af 1600x and cytop cytop 809ainto one bifunctionalized dielectric nanolayer. Before assembly, photoresist was stripped with acetone and methanol, and the electrode array was annealed at 175c for 2 min. In the classical theoretical analysis of ewod systems, the dielectric layer and conductive fluid are normally assumed to be a. Electrowetting without electrolysis on selfhealing. Characterization of dielectric films for electrowetting on.
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