Papers by Armando Arpys Arevalo Carreno
The development of a polyimide and metals multi-user surface micro-machining process for Micro-el... more The development of a polyimide and metals multi-user surface micro-machining process for Micro-electro-mechanical Systems (MEMS) is presented. The process was designed to be as general as possible, and designed to be capable to fabricate different designs on a single silicon wafer. The process was not optimized with the purpose of fabricating any one specific device but can be tweaked to satisfy individual needs depending on the application. The fabrication process uses Polyimide as the structural material and three separated metallization layers that can be interconnected depending on the desired application. The technology allows the development of out-of-plane compliant mechanisms, which can be combined with six variations of different physical principles for actuation and sensing on a single processed silicon wafer. These variations are: electrostatic motion, thermal bimorph actuation, capacitive sensing, magnetic sensing, thermocouple-based sensing and radio frequency transmiss...
This paper reports the structural solid mechanic simulation of a MEMS out-of-plane platform that ... more This paper reports the structural solid mechanic simulation of a MEMS out-of-plane platform that provides thermal and electrical isolation for a device built on it. When assemble, the platform lifted for approximately 400 µm above the substrate level. A mechanical stress analysis is then presented in order to evaluate the feasibility of building it using commonly used materials in MEMS. Our analysis showed that polymeric materials such as polyimide and SU8 may undergo a localized plastic deformation but are not likely to fail upon assembly. Polysilicon on the contrary, showed high failure probability.
INTRODUCTION: Micro Electro Mechanical Systems (MEMS) are fabricated with an in-plane fabrication... more INTRODUCTION: Micro Electro Mechanical Systems (MEMS) are fabricated with an in-plane fabrication technology. Out-of-plane structures can be designed to be assembled to provide thermal and electrical isolation from the substrate [1 -3]. These isolations can potentially improve the performance of a range of MEMS devices by decreasing any unwanted coupling effects or parasitic losses from the devices to a lossy substrate. One of the interesting out-of-plane mechanism is the Buckled Cantilever Plate (BCP) [1,3,4] and the other one is the Tsang Suspension [5,6]. We have designed and simulated BCP out-of-plane structures with thermal dimorph actuators to be able to control the angular position of the assembled plate Fig. 1. RESULTS: For the COMSOL Multiphysics® simulation we first created a 3D model of the structure in the COMSOL environment. Each domain was assigned its corresponding material, using Polyamide as the structural layer. We use setup the boundary condition that represent th...
INTRODUCTION: The role of stretchable electronics systems allows the design of new reconfigurable... more INTRODUCTION: The role of stretchable electronics systems allows the design of new reconfigurable macro-electronics, that extends a device capability to function as a distributed sensor network which can potentially be used for wearable electronics. At the moment such devices are primarily based on polymeric materials such as PDMS or Polyimide [1,2]. Nevertheless, silicon has been the predominant material in electronics for decades. For this reason, we selected silicon as the base material structure for a hexagonal islands network, which are connected through spiral springs to form an ultra-stretchable arrangement [3,4]. In this work we simulated a spiral tether structure for stretchable and adaptable electronic systems. The spirals interconnect several hexagonal islands as show in (Figure 1). USE OF COMSOL MULTIPHYSICS®: The Finite Element Method (FEM) used to validate the functionality of the spiral structure. COMSOL capabilities to simulate Micro Electro Mechanical Systems (MEMS)...
Sensors and Actuators A: Physical, 2021
This report presents a review of progress on peristaltic micropumps since their emergence, which ... more This report presents a review of progress on peristaltic micropumps since their emergence, which have been widely used in many research fields from biology to aeronautics. This paper summarizes different techniques that have been used to mimic this elegant physiological transport mechanism that is commonly found in nature. The analysis provides definitions of peristaltic micropumps and their different features, distinguishing them from other mechanical micropumps. Important parameters in peristalsis are presented, such as the operating frequency, stroke volume, and various actuation sequences, along with introducing design rules and analysis for optimizing actuation sequences. Actuation methods such as piezoelectric, motor, pneumatic, electrostatic, and thermal are discussed with their advantages and disadvantages for application in peristaltic micropumps. This review evaluates research efforts over the past 30 years with comparison of key features and outputs, and suggestions for future development. The analysis provides a starting point for researchers designing peristaltic micropumps for a broad range of applications.
Genes, Jan 4, 2018
In this paper, we present a two-phase microfluidic system capable of incubating and quantifying m... more In this paper, we present a two-phase microfluidic system capable of incubating and quantifying microbead-based agglutination assays. The microfluidic system is based on a simple fabrication solution, which requires only laboratory tubing filled with carrier oil, driven by negative pressure using a syringe pump. We provide a user-friendly interface, in which a pipette is used to insert single droplets of a 1.25-µL volume into a system that is continuously running and therefore works entirely on demand without the need for stopping, resetting or washing the system. These assays are incubated by highly efficient passive mixing with a sample-to-answer time of 2.5 min, a 5⁻10-fold improvement over traditional agglutination assays. We study system parameters such as channel length, incubation time and flow speed to select optimal assay conditions, using the streptavidin-biotin interaction as a model analyte quantified using optical image processing. We then investigate the effect of chan...
2016 IEEE 11th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2016
This paper presents a capacitive sensor for monitoring parallel microfluidic droplet generation. ... more This paper presents a capacitive sensor for monitoring parallel microfluidic droplet generation. The great electric permittivity difference between common droplet microfluidic fluids such as air, oil and water (εoil ≈ 2-3 and εwater ≈ 80.4), allows for accurate detection of water in oil concentration changes. Capacitance variations as large as 10 pF between a channel filled with water or dodecane, are used to continuously monitor the output of a parallelization system producing 150 μl/min of water in dodecane emulsions. We also discuss a low cost fabrication process to manufacture these capacitive sensors, which can be integrated to different substrates.
2016 IEEE 11th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2016
In this paper we present the fabrication and characterization of an array of electrostatic acoust... more In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3μm air gap. The membrane is made out 5μm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.
2016 IEEE 11th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2016
In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. T... more In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50' μm made of polyimide. The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with different voltages obtaining good sound output levels by using only 3 V.
2016 IEEE 11th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2016
This work reports on a quantitative study of the incubation of a microbead-based agglutination as... more This work reports on a quantitative study of the incubation of a microbead-based agglutination assay inside a microfluidic system. In this system, a droplet (1.25μL) consisting of a mixture of functionalized microbeads and analyte is flowed through a 0.51mm internal diameter silicone tube. Hydrodynamic forces alone produce a very efficient mixing of the beads within the droplet. We tested the agglutination at different speeds and show a robust response at the higher range of speeds (150 - 200μL/min), while also reaching a completion in the agglutination process. At these velocities, a length of 180cm is shown to be sufficient to confidently measure the agglutination assay, which takes between 2.5 - 3 minutes. This high throughput quantification method has the potential of accelerating the measurements of various types of biomarkers, which can greatly benefit the fields of biology and medicine.
2016 IEEE 11th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2016
This paper reports on a radio frequency micro-strip T-resonator that is integrated to a parallel ... more This paper reports on a radio frequency micro-strip T-resonator that is integrated to a parallel droplet microfluidic system. The T-resonator works as a feedback system to monitor uniform droplet production and to detect, in real-time, any malfunctions due to channel fouling or clogging. Emulsions at different W/O flow-rate ratios are generated in a microfluidic device containing 8 parallelized generators. These emulsions are then guided towards the RF sensor, which is then read using a Network Analyzer to obtain the frequency response of the system. The proposed T-resonator shows frequency shifts of 45MHz for only 5% change in the emulsion's water in oil content. These shifts can then be used as a feedback system to trigger alarms and notify production and quality control engineers about problems in the droplet generation process.
Nano Energy, 2017
Paper has been an essential material in our daily life since ancient times. Its affordability, ac... more Paper has been an essential material in our daily life since ancient times. Its affordability, accessibility, adaptability, workability and its easiness of usage makes it an attractive structural material to develop many kind of technologies such as flexible electronics, energy storage and harvesting devices. Additionally, the scientific community has increased its interest on waste heat as an environmentally friendly energy source to support the increasing energy demand. Therefore, in this paper we described two affordable and flexible thermoelectric nanogenerators (TEGs) developed on paper substrates by the usage of simple micromachining and microfabrication techniques. Moreover, they exhibit mechanical stability and adaptability (through folding and cutting techniques) for a diverse set of scenarios where vertical or horizontal schemes can be conveniently used depending on the final application. The first TEG device, implemented on standard paper, generated a power of
Nano Energy, 2016
To achieve higher power output from a thermoelectric generator (TEG), one needs to maintain a lar... more To achieve higher power output from a thermoelectric generator (TEG), one needs to maintain a larger temperature difference between hot and cold end. In that regard, a stretchable TEG can be interesting to adaptively control the temperature difference. Here we show, the development of simple yet versatile and highly stretchable thermoelectric generators (TEGs), by combining well-known inorganic thermoelectric materials Bismuth Telluride and Antimony Telluride (Bi 2 Te 3 and Sb 2 Te 3) with organic substrates (Off-Stoichiometry Thiol-Enes polymer platform-OSTE, polyimide or paper) and novel helical architecture (double-arm spirals) to achieve over 100% stretchability. First, an OSTE-based TEG design demonstrates higher open circuit voltage generation at 100% strain than at rest,
Advanced Materials Technologies, 2016
Lab on a chip, Aug 6, 2016
Scaled-up production of microfluidic droplets, through the parallelization of hundreds of droplet... more Scaled-up production of microfluidic droplets, through the parallelization of hundreds of droplet generators, has received a lot of attention to bring novel multiphase microfluidics research to industrial applications. However, apart from droplet generation, other significant challenges relevant to this goal have never been discussed. Examples include monitoring systems, high-throughput processing of droplets and quality control procedures among others. In this paper, we present and compare capacitive and radio frequency (RF) resonator sensors as two candidates that can measure the dielectric properties of emulsions in microfluidic channels. By placing several of these sensors in a parallelization device, the stability of the droplet generation at different locations can be compared, and potential malfunctions can be detected. This strategy enables for the first time the monitoring of scaled-up microfluidic droplet production. Both sensors were prototyped and characterized using emu...
2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), 2016
This paper reports on the design and fabrication of MEMS actuator arrays suitable for Digital Sou... more This paper reports on the design and fabrication of MEMS actuator arrays suitable for Digital Sound reconstruction and Parametric Directional Loudspeakers. Two distinct versions of the device were fabricated: one using the electrostatic principle actuation and the other one, the piezoelectric principle. Both versions used similar membrane dimensions, with a diameter of 500 μm. These devices are the smallest Micro-Machined Ultrasound Transducer (MUT) arrays that can be operated for both modes: Digital Sound Reconstruction and Parametric Loudspeaker. The chips consist of an array with 256 transducers, in a footprint of 12 mm by 12 mm. The total single chip size is: 2.3 cm by 2.3 cm, including the contact pads.
Journal of Micromechanics and Microengineering, 2016
In this study, we demonstrate analytically and experimentally the excitations of the higher order... more In this study, we demonstrate analytically and experimentally the excitations of the higher order modes of vibrations in electrostatically actuated clamped–clamped microbeam resonators. The concept is based on using partial electrodes with shapes that induce strong excitation of the mode of interest. The devices are fabricated using polyimide as a structural layer coated with nickel from the top and chrome and gold layers from the bottom. Experimentally, frequency sweeps with different electro-dynamical loading conditions are shown to demonstrate the excitation of the higher order modes of vibration. Using a half electrode, the second mode is excited with high amplitude of vibration compared with almost zero response using the full electrode. Also, using a two-third electrode configuration is shown to amplify the third mode resonance amplitude compared with the full electrode under the same electrical loading conditions. An analytical model is developed based on the Euler–Bernollui beam model and the Galerkin method to simulate the device response. Good agreement between the simulation results and the experimental data is reported.
Sensors and Actuators A: Physical, 2015
Highlights We propose a MEMS logic device, which is capable, of performing INVERTER, AND, NAND,... more Highlights We propose a MEMS logic device, which is capable, of performing INVERTER, AND, NAND, NOR, and OR gates using one physical structure within an operating range of 0-10 volts. It can also perform XOR and XNOR with one access inverter using the same structure with different electrical interconnects. We use here a non-conducting structure (Polyimide) with patterning of a conductive metal layer to form the gate electrode. This patterned layer allows independent control of mechanical and electrical properties, which provides flexibility and control over the biasing of the electrodes. This allows more gate functions than previously possible using a single basic gate design. Theoretical lumped parameter model for torsion based MEMS actuator is also presented.
Micro & Nano Letters, 2015
The integration of thermal bimorph actuators and buckled cantilever structures to form an out-of-... more The integration of thermal bimorph actuators and buckled cantilever structures to form an out-of-plane plate with adjustable angular positions is reported. This structure could be used as a platform to build other transducers such as optical micromirrors, scanning antennas, switches or low-frequency oscillators. The electromechanical characterisation has shown that these structures can adjust their angular position by 6° when they are operated using a DC source. The thermal characterisation performed by an infrared camera showed that the heat-affected zone reaches a maximum temperature of 125°C while the rest of the structure remains unaffected by the generated heat.
Journal of Micromechanics and Microengineering, 2015
This paper reports the design of a proof-of-concept drug delivery device that is actuated using t... more This paper reports the design of a proof-of-concept drug delivery device that is actuated using the bubbles formed during electrolysis. The device uses a platinum (Pt) coated nickel (Ni) metal foam and a solid drug in reservoir (SDR) approach to improve the device's performance. This electrochemically-driven pump has many features that are unlike conventional drug delivery devices: it is capable of pumping periodically and being refilled automatically; it features drug release control; and it enables targeted delivery. Pt-coated metal foam is used as a catalytic reforming element, which reduces the period of each delivery cycle. Two methods were used for fabricating the Pt-coated metal: sputtering and electroplating. Of these two methods, the sputtered Pt-coated metal foam has a higher pumping rate; it also has a comparable recombination rate when compared to the electroplated Pt-coated metal foam. The only drawback of this catalytic reformer is that it consumes nickel scaffold. Considering long-term applications, the electroplated Pt metal foam was selected for drug delivery, where a controlled drug release rate of 2.2 μg ± 0.3 μg per actuation pulse was achieved using 4 mW of power.
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Papers by Armando Arpys Arevalo Carreno