scholarly journals SU-8 as Hydrophobic and Dielectric Thin Film in Electrowetting-on-Dielectric Based Microfluidics Device

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Vijay Kumar ◽  
N. N. Sharma
Keyword(s):  
Electrode Array ◽  
Spherical Shape ◽  
Dielectric Thin Film ◽  
Electrowetting On Dielectric ◽  
Design And Optimization ◽  
Microfluidic Flow ◽  
Current Design ◽  
Droplet Movement ◽  
Hydrophobic Layer ◽  
On Chip

Electrowetting-on-dielectric (EWOD) based droplet actuation in microfluidic chip is designed and fabricated. EWOD is used as on-chip micro-pumping scheme for moving fluid digitally in Lab-on-a-chip devices. For enabling this scheme, stacked deposition of thin dielectric and hydrophobic layer in that order between microchannel and electrodes is done. The present paper investigates the potential use of SU-8 as hydrophobic layer in conjunction of acting as dielectric in the device. The objective for the investigation is to lower the cost and a thin simplification in fabrication process of EWOD-based devices. We have done design and optimization of dimensions of electrode array including gap between arrays for EWOD micropump. Design and optimization are carried out in CoventorWare. The designing is followed by fabrication of device and analysis for droplet motion. The fabrication of the device includes array of electrodes over the silicon surface and embedding them in hydrophobic SU-8 layer. Water droplet movement in the order of microliter of spherical shape is demonstrated. It has been shown that an SU-8 microchannel in the current design allows microfluidic flow at tens of voltages comparable with costlier and more complicated to fabricate designs reported in the literature.

scholarly journals Electrowetting-on-Dielectric Based Economical Digital Microfluidic Chip on Flexible Substrate by Inkjet Printing

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1113
Author(s):  
He Wang ◽  
Liguo Chen
Keyword(s):  
Inkjet Printing ◽  
Material Selection ◽  
Flexible Substrate ◽  
Digital Microfluidics ◽  
Production Capacity ◽  
Electrode Array ◽  
Circuit Board ◽  
Electrowetting On Dielectric ◽  
Hydrophobic Layer ◽  
Pet Substrate

In order to get rid of the dependence on expensive photolithography technology and related facilities, an economic and simple design and fabrication technology for digital microfluidics (DMF) is proposed. The electrodes pattern was generated by inkjet printing nanosilver conductive ink on the flexible Polyethylene terephthalate (PET) substrate with a 3D circuit board printer, food wrap film was attached to the electrode array to act as the dielectric layer and Teflon® AF was sprayed to form a hydrophobic layer. The PET substrate and food wrap film are low cost and accessible to general users. The proposed flexible DMF chips can be reused for a long time by replacing the dielectric film coated with hydrophobic layer. The resolution and conductivity of silver traces and the contact angle and velocity of the droplets were evaluated to demonstrate that the proposed technology is comparable to the traditional DMF fabrication process. As far as the rapid prototyping of DMF is concerned, this technology has shown very attractive advantages in many aspects, such as fabrication cost, fabrication time, material selection and mass production capacity, without sacrificing the performance of DMF. The flexible DMF chips have successfully implemented basic droplet operations on a square and hexagon electrode array.

Transporting Carrier With Droplets Driven by Electrowetting-on-Dielectric Effect

2021 ◽  
Author(s):  
Jian-Zhang (Kenny) He ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Effective Distance ◽  
Control Software ◽  
Early 19Th Century ◽  
Electrowetting On Dielectric ◽  
Dielectric Effect ◽  
Droplet Movement ◽  
Hydrophobic Layer ◽  
Finger Electrode

Abstract In the early 19th century, Thomas Young (1805) and Pierre Simon Laplace (1806) published the concept of fluid surface tension, which made great contributions to the theory of surface tension. Many scholars continued to study electrowetting-on-dielectric (EWOD) technology, hoping to effectively control the movement of droplets, to make a lot of microchannels in biomedical and life applications. The purpose of dielectric and hydrophobic layer is to prevent the droplet from short circuiting when the electrode moves, and the increase of hydrophobic layer will improve the smoothness of droplet movement. EWOD technology is used in this research as the prelude of the development of soft robot. Through the combination of finger electrode and electrowetting-on-dielectric technology, a carrier is designed. The drop is driven by Arduino and LabVIEW control software, and the carrier can be moved effectively. The effective distance between the finger electrodes was found out from the experiment to change the contact angle of the drop. Drop material will use two kinds of materials, PC and mixed liquid (PC, UV), try to change the contact angle and its strength through the voltage of 0–250V, so as to find out the maximum force and suitable contact angle, hoping to support the carrier effectively. Finally, the carrier will be transported to the designated position by using drops.

scholarly journals Development of a Mobile Analytical Chemistry Workstation Using a Silicon Electrochromatography Microchip and Capacitively Coupled Contactless Conductivity Detector

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 239
Author(s):  
Yineng Wang ◽  
Xi Cao ◽  
Walter Messina ◽  
Anna Hogan ◽  
Justina Ugwah ◽  
...  
Keyword(s):  
Capillary Electrochromatography ◽  
High Efficiency ◽  
Device Fabrication ◽  
Capacitively Coupled ◽  
Packaging Design ◽  
Design And Optimization ◽  
Nanofabrication Technique ◽  
On Chip ◽  
Silicon Based ◽  
Rapid Separations

Capillary electrochromatography (CEC) is a separation technique that hybridizes liquid chromatography (LC) and capillary electrophoresis (CE). The selectivity offered by LC stationary phase results in rapid separations, high efficiency, high selectivity, minimal analyte and buffer consumption. Chip-based CE and CEC separation techniques are also gaining interest, as the microchip can provide precise on-chip control over the experiment. Capacitively coupled contactless conductivity detection (C4D) offers the contactless electrode configuration, and thus is not in contact with the solutions under investigation. This prevents contamination, so it can be easy to use as well as maintain. This study investigated a chip-based CE/CEC with C4D technique, including silicon-based microfluidic device fabrication processes with packaging, design and optimization. It also examined the compatibility of the silicon-based CEC microchip interfaced with C4D. In this paper, the authors demonstrated a nanofabrication technique for a novel microchip electrochromatography (MEC) device, whose capability is to be used as a mobile analytical equipment. This research investigated using samples of potassium ions, sodium ions and aspirin (acetylsalicylic acid).

Analysis of Thermal Properties of Power Multifinger HEMT Devices

2018 ◽  
Author(s):  
Aleš Chvála ◽  
Robert Szobolovszký ◽  
Jaroslav Kováč ◽  
Martin Florovič ◽  
Juraj Marek ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Thermal Management ◽  
High Electron Mobility Transistor ◽  
Structure Design ◽  
High Electron ◽  
Design And Optimization ◽  
Chip Temperature ◽  
Materials Used ◽  
On Chip ◽  
Measurement Approach

In this paper, several methods suitable for real time on-chip temperature measurements of power AlGaN/GaN based high-electron mobility transistor (HEMT) grown on SiC substrate are presented. The measurement of temperature distribution on HEMT surface using Raman spectroscopy is presented. We have deployed a temperature measurement approach utilizing electrical I-V characteristics of the neighboring Schottky diode under different dissipated power of the transistor heat source. These methods are verified by measurements with micro thermistors. The results show that these methods have a potential for HEMT analysis in thermal management. The features and limitations of the proposed methods are discussed. The thermal parameters of materials used in the device are extracted from temperature distribution in the structure with the support of 3-D device thermal simulation. The thermal analysis of the multifinger power HEMT is performed. The effects of the structure design and fabrication processes from semiconductor layers, metallization, and packaging up to cooling solutions are investigated. The analysis of thermal behavior can help during design and optimization of power HEMT.

Numerical and theoretical analyses of the dynamics of droplets driven by electrowetting on dielectric in a Hele-Shaw cell

2018 ◽  
Vol 839 ◽  
pp. 468-488 ◽  
Author(s):  
Yasufumi Yamamoto ◽  
Takahiro Ito ◽  
Tatsuro Wakimoto ◽  
Kenji Katoh
Keyword(s):  
Theoretical Model ◽  
Contact Line ◽  
Three Dimensional ◽  
Simulation Method ◽  
Movement Speed ◽  
Electrowetting On Dielectric ◽  
Moving Contact Line ◽  
Moving Contact ◽  
Droplet Movement ◽  
Hele Shaw Cell

Droplet movement by electrowetting on dielectric (EWOD) in a Hele-Shaw cell is analysed theoretically and numerically. 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. The simulation method for numerical analyses is constructed by using the Young–Lippmann equation to represent EWOD and the generalised Navier boundary condition to represent the moving contact line in the context of the front-tracking method. With an adjusted slip parameter, the present full three-dimensional numerical simulation reproduces well the shape evolution and movement speed of droplets as observed experimentally. We verify the proposed theoretical model in numerical experiments with various shapes and voltages. Furthermore, we analyse theoretically the behaviour of the contact line at the onset of droplet motion as observed in the simulation and experiment, and we are able to estimate very well the time scale on which the contact angle changes.

scholarly journals A mm-Sized Free-Floating Wireless Implantable Opto-Electro Stimulation Device

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 621
Author(s):  
Yaoyao Jia ◽  
Yan Gong ◽  
Arthur Weber ◽  
Wen Li ◽  
Maysam Ghovanloo
Keyword(s):  
Electrical Stimulation ◽  
Large Scale ◽  
Electrode Array ◽  
Cmos Process ◽  
Optical Stimulation ◽  
In Vivo Experiments ◽  
Stimulation Mode ◽  
Shift Keying ◽  
On Chip

Towards a distributed neural interface, consisting of multiple miniaturized implants, for interfacing with large-scale neuronal ensembles over large brain areas, this paper presents a mm-sized free-floating wirelessly-powered implantable opto-electro stimulation (FF-WIOS2) device equipped with 16-ch optical and 4-ch electrical stimulation for reconfigurable neuromodulation. The FF-WIOS2 is wirelessly powered and controlled through a 3-coil inductive link at 60 MHz. The FF-WIOS2 receives stimulation parameters via on-off keying (OOK) while sending its rectified voltage information to an external headstage for closed-loop power control (CLPC) via load-shift-keying (LSK). The FF-WIOS2 system-on-chip (SoC), fabricated in a 0.35-µm standard CMOS process, employs switched-capacitor-based stimulation (SCS) architecture to provide large instantaneous current needed for surpassing the optical stimulation threshold. The SCS charger charges an off-chip capacitor up to 5 V at 37% efficiency. At the onset of stimulation, the capacitor delivers charge with peak current in 1.7–12 mA range to a micro-LED (µLED) array for optical stimulation or 100–700 μA range to a micro-electrode array (MEA) for biphasic electrical stimulation. Active and passive charge balancing circuits are activated in electrical stimulation mode to ensure stimulation safety. In vivo experiments conducted on three anesthetized rats verified the efficacy of the two stimulation mechanisms. The proposed FF-WIOS2 is potentially a reconfigurable tool for performing untethered neuromodulation.

Design and Optimization of Reaction Chamber and Detection System in Dynamic Labs-on-Chip for Proteins Detection

2013 ◽  
Vol 60 (8) ◽  
pp. 2161-2166 ◽  
Author(s):  
Maya Briani ◽  
Giacomo Germani ◽  
Eugenio Iannone ◽  
Maurizio Moroni ◽  
Roberto Natalini
Keyword(s):  
Detection System ◽  
Reaction Chamber ◽  
Design And Optimization ◽  
On Chip

Design and optimization of on-chip capillary electrophoresis

2002 ◽  
Vol 23 (16) ◽  
pp. 2729-2744 ◽  
Author(s):  
Rajiv Bharadwaj ◽  
Juan G. Santiago ◽  
Bijan Mohammadi
Keyword(s):  
Capillary Electrophoresis ◽  
Design And Optimization ◽  
On Chip
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