Journal of Micromechanics and Microengineering最新文献

{"title":"Inexpensive and rapid fabrication of PDMS microfluidic devices for biological testing applications using low cost commercially available 3D printers","authors":"Megala Ramasamy, Brandon Ho, C. Phan, N. Qin, C. Ren, Lyndon Jones","doi":"10.1088/1361-6439/acf2a7","DOIUrl":"https://doi.org/10.1088/1361-6439/acf2a7","url":null,"abstract":"Polydimethylsiloxane (PDMS) elastomers have been extensively used in the development of microfluidic devices, capable of miniaturizing biomolecular and cellular assays to the microlitre and nanolitre range, thereby increasing the throughput of experimentation. PDMS has been widely used due to its optical clarity and biocompatibility, among other desirable physical and chemical properties. Despite the widespread use of PDMS in microfluidic devices, the fabrication process typically via soft lithography technology requires specialized facilities, instruments, and materials only available in a limited number of laboratories. To expand microfluidic research capabilities to a greater scientific population, we developed and characterized a simple and robust method of fabricating relatively inexpensive PDMS microfluidic devices using readily available reagents and commercially available three-dimensional (3D) printers. The moulds produced from the 3D printers resolve designed microfluidic channel features accurately with high resolution (>100 µm). The critical physical and chemical post-processing modifications we outline here are required to generate functional and optically clear microfluidic devices.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44891007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Splashing of droplet under the vibration effect of flexible membrane","authors":"Sanghyun Lee, Sangmin Lee","doi":"10.1088/1361-6439/acf13c","DOIUrl":"https://doi.org/10.1088/1361-6439/acf13c","url":null,"abstract":"The impact dynamics of a droplet falling onto a substrate is significant in various applications such as inkjet printing, spray coating, and bioprinting. Generally, several factors, such as the fluid properties (e.g. viscosity or surface tension) and substrate characteristics (e.g. surface roughness or flexibility) govern whether falling droplets spread or splash. In this study, we experimentally investigate droplet impact dynamics on a thin, flexible membrane for various Weber numbers (230 < We < 600) and membrane stiffnesses, which can be controlled by the applied tensile force. In addition, the effect of membrane vibration on impact behavior is considered. In the high Weber number regime, splashing is dominant, regardless of the membrane stiffness. In contrast, in the low Weber number regime, a transition between splashing and deposition is observed, depending on the membrane stiffness. In short, flexible membrane vibration induces droplet splashing despite the insufficient kinetic energy of the droplet. Increasing the stiffness of the membrane contributes to the suppression of droplet splashing by minimizing membrane vibration.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47158836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Capillary enhanced phase change in a microfabricated self-oscillating fluidic heat engine (SOFHE)","authors":"N. Karami, A. Tessier-Poirier, É. Léveillé, A. Amnache, L. Fréchette","doi":"10.1088/1361-6439/acf13b","DOIUrl":"https://doi.org/10.1088/1361-6439/acf13b","url":null,"abstract":"This paper reports the design, fabrication, and characterization of a miniaturized version of a self-oscillating fluidic heat engine (SOFHE) for thermal energy harvesting. This new design includes capillary corners of a square cross-section, as well as an etched capillary path on the bottom wall that improves the performance in terms of stability and mechanical power owing to the enhanced phase change. The engine consists of a vapor bubble trapped in a microchannel by an oscillating liquid plug (acting as a piston) set in motion by periodic evaporation and condensation in the vapor bubble. The underlying physics of the oscillations is similar to those of a single-branch pulsating heat pipe. The channel is microfabricated by anodically bonding a grooved glass wafer (top and sidewalls) to a silicon wafer (bottom wall). To further increase the phase change, two more channels are fabricated with an etched capillary path on the bottom wall at two different widths of 25 and 50 µm and a depth of 100 µm. This is the first miniaturized SOFHE that generates a reliable amplitude in the millimeter range. By measuring the change in the volume of the vapor bubble and the frequency, we calculated the change in pressure using the momentum balance on the liquid plug, and then calculated the work, mechanical power, and power density. We observed that the addition of the etched capillary path at a width of 50 µm increased the amplitude (from 1.6 to 4 mm) leading to a fivefold increase in the generated power (from 8 to 40 µW). This study opens a new path towards designing different wicking structures to maximize the amplitude and power density of the SOFHE, making it a promising thermal energy harvester to power wireless sensors.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":"33 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60643102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of rolled fibrous microstructure on fatigue properties of extruded Cu-5Al planar micro springs","authors":"Feiyin Li, Xiubing Wang, Shaojie Ma, X. Dong, Xinping Zhang","doi":"10.1088/1361-6439/acf13a","DOIUrl":"https://doi.org/10.1088/1361-6439/acf13a","url":null,"abstract":"Planar micro spring is an important elastic component in microelectromechanical system devices, and one of its main failures is fatigue. In this work, a new method to improve the cycles of a planar micro spring by introducing pre-rolled fibrous microstructure was proposed. Cu-5Al alloy billets with a fibrous microstructure rolled at room temperature with a reduction ratio of 70% were obtained. Three types of planar micro springs with fibrous microstructure were prepared through extrusion by varying the angle between the fibrous microstructure direction and the extrusion direction. Fatigue tests were conducted using a customized micro-fatigue test system. The best fatigue performance was obtained by preparing the micro springs with the fibrous microstructure direction perpendicular to the extrusion direction, while the worst fatigue performance was obtained by preparing the planar micro springs with the fibrous microstructure direction parallel to the extrusion direction. The fibrous microstructure direction affected the local strain in the micro springs. The fibrous microstructure slightly affected the location of the crack initiation region but significantly affected the area of crack initiation and steady-state expansion region of the micro spring. The fatigue life cycle of extruded Cu-5Al alloy planar micro spring with the pre-rolled fibrous microstructure improved by 58% more than that of extruded Cu-7Al alloy planar micro spring without the pre-rolled fibrous microstructure. Micro spring fatigue life cycle decreased with increasing strain amplitude. This work provides a new approach for preparing planar micro springs with high fatigue performance.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44302568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of SiO2 protective layer on LiNbO3 structured SAW resonators and temperature characteristics study","authors":"Liu Qiang, Wen-Lin Yang, Cheng Chi, Hongyuan Li, Xu Hong","doi":"10.1088/1361-6439/acef33","DOIUrl":"https://doi.org/10.1088/1361-6439/acef33","url":null,"abstract":"In this paper, using LiNbO3 as the piezoelectric substrate, Pt as the electrode and SiO2 as the protective layer, a multi-physics field coupled finite element model was used to investigate the effect of the protective layer thickness on the Rayleigh wave propagation characteristics, and the relationship between the protective layer thickness and the frequency–temperature coefficient TCF and electromechanical coupling coefficient K 2 is established. The frequency characteristics of the device and the microscopic changes of the electrode and substrate structures under high temperature were analyzed experimentally. The results show that no acoustic mode shift occurs when the normalized thickness is less than 31.25%. As the thickness of the protective layer increases, the vibration displacement in the direction of L wave, SH wave and SV wave decreases, and the thickness of the protective layer can be increased appropriately to reduce the interference of SH wave to Rayleigh wave; |TCF| decreases with increasing thickness of the protective layer. Changes in the thickness of the protective layer at different temperatures lead to fluctuations in K 2; the protective layer structure leads to a slight decrease in Q value. As the temperature increases, the fluctuation of the resonant frequency of the SAW resonator increases. The SiO2 protective layer can effectively protect LiNbO3 materials while improving the high-temperature working stability of Pt electrodes.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48034923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel micro-device for simultaneous separation-trapping and double-trapping of particles by using dielectrophoresis: numerical and experimental study","authors":"M. Aghdasi, M. Nazari, Sareh Yonesi","doi":"10.1088/1361-6439/acef32","DOIUrl":"https://doi.org/10.1088/1361-6439/acef32","url":null,"abstract":"Dielectrophoretic (DEP) force is a useful tool for manipulating particles in microfluidic systems. It is affected by the frequency of the applied electric field, which can be varied to produce repellent and attractive forces depending on the dielectric properties of particles and the media. In this work, two electric fields with different frequency are used to simultaneously separate and trap particles as well as double-trap particles by utilizing the DEP force. Initially, a single-vial microchannel was proposed to study the impact of the frequency and voltage on three types of electrodes: concentrator, repellent, and absorbing. The goal was to examine their efficacy in trapping a group of particles within the vial while separating and ejecting another group of particles from the microchannel. Performance graphs were used to determine the optimal voltages for the electrodes. Subsequently, an additional vial is incorporated into the microchannel to enable the double-trapping of particles with varying sizes and properties. With the optimal design, particles of varying sizes and properties can be trapped in separate vials within the microchannel. For the first time, the performance cartography of the proposed system has been assessed, enabling the identification of the optimal values and intelligent separations. Validation is conducted in two steps. Firstly, numerical findings are compared to previous experimental results to verify the accuracy of the numerical approach. Secondly, a microchip is fabricated, tested, and compared to numerical results using yeast cells to assess system efficiency and enhance the reliability of the numerical technique.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47624880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional AC electroosmotic micropump with high power density","authors":"M. Watanabe, Kazuhiro Yoshida, Joon-wan Kim, S. Eom, S. Yokota","doi":"10.1088/1361-6439/acef31","DOIUrl":"https://doi.org/10.1088/1361-6439/acef31","url":null,"abstract":"This paper presents a novel three-dimensional alternating current electroosmosis (ACEO) micropump with high power density. ACEO is a phenomenon to generate a flow of a liquid such as water by applying an AC voltage to the liquid. Using a specific configuration, a net flow due to ACEO becomes unidirectional and an ACEO micropump can be constructed. Many ACEO micropumps have been proposed; however, most of them are of the planar type, and their output power per device volume is not sufficiently high for applications such as micro fluid power sources for micro total analysis systems, lab-on-a-chips, biomedical microelectromechanical systems (bio-MEMSs), soft microactuators, and soft microrobots. To achieve a higher output power density, in this study, we proposed an ACEO micropump using an array of plate-cylinder electrodes, which is called PC-ACEO-MP. To induce unidirectional flow efficiently, a square pole-slit electrodes ACEO micropump called SS-ACEO-MP has been proposed using asymmetrical pillar-shaped electrodes. PC-ACEO-MP is an extension of SS-ACEO-MP with a three-dimensional structure. First, the finite element method simulations were performed and the results showed that PC-ACEO-MP has the potential to realize high output power with a 1 cm3 effective pump volume using large numbers of plate-cylinder electrodes connected in parallel and in series. Second, a fabrication method using MEMS fabrication process, including electroplating, was proposed and developed for a micro-holed electrode plate that forms parallel cylinder electrodes. The validity of the proposed process was confirmed by fabricating large models and micro-models of the micro-holed electrode plate. The diameter and number of microholes were 10 μm and 36 100, respectively, for the large models and 3 μm and 65 500, respectively, for the micro models. Finally, PC-ACEO-MPs were constructed and their promising pumping characteristics were clarified through experiments using deionized water. The estimated power density was approximately 400 times higher than that of the former high output power ACEO micropump.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45616033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on acoustic-induced microbubbles fusion","authors":"Shaobo Jin, N. Cao, G. Ye, P. Wang, Shizhang Dong, Zenghao Liu","doi":"10.1088/1361-6439/acee87","DOIUrl":"https://doi.org/10.1088/1361-6439/acee87","url":null,"abstract":"Droplets/microbubbles fusion technology is a key technology for many biochemical medical applications. Here, an acoustic-controlled approach to drive microbubble fusion based on focused surface acoustic wave (FSAW) is presented. When passing through the arc-shaped channel, adjacent microbubbles will decelerate, contact, and fuse induced by the FSAWs. Due to the cooperation of the FSAW and the arc-shaped flow channel structure, the microbubbles are more easily captured and fused with the adjacent microbubbles. The effects of input voltage and pressure input parameters on the microbubble fusion are studied. Relying on electrical input parameters, microbubble fusion can be effectively achieved, providing a new idea for precise gas fuse control. The regulation of the microbubbles fusion by FSAW is revealed, showing potential in the applications of the precise control of gases on a microfluidic chip.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49545656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mass transfer characteristics at cathode/electrolyte interface during electrodeposition of nickel microcolumns with various aspect ratios","authors":"Yanzhuo Dong, Bingyan Jiang, D. Drummer, Lu Zhang","doi":"10.1088/1361-6439/acee8a","DOIUrl":"https://doi.org/10.1088/1361-6439/acee8a","url":null,"abstract":"The filling behavior of electrodeposited microcolumns is strongly influenced by the mass transfer characteristics at the cathode/electrolyte interface. This study aims to elucidate the influence of the mass transfer characteristics (ion supplementation via diffusion and ion consumption via deposition) on the electrodeposition of microcolumns, thus providing feasible solutions for improving void defects with different feature sizes. The results indicate that ion consumption plays an important role in the mass transfer within large-width microcavities (100 μm). For large-width microcolumns, longer electroforming times lead to higher ion consumption, resulting in nonuniform ion concentration distribution, and consequently uneven deposition rates along the microcavity wall. In microcavities with high aspect ratio (5:1), ion supplementation plays a major role. The low ion supplementation rate does not support a uniform deposition, resulting in a large void defect and a low filling ratio in the deposited microcolumns. Therefore, reducing the ion consumption rate by decreasing the current density from 1 A dm−2 to 0.25 A dm−2 can effectively increase the filling ratio in large-width microcolumns with no significant effect on high aspect ratio microcolumns. On the contrary, the pulse reverse current (forward pulse current density 1 A dm−2, reverse pulse current density 2 A dm−2, frequency 1 Hz, forward pulse duty cycle 0.9) can increase the filling ratio in the high aspect ratio microcolumns by accelerating ion supplementation through dissolution of the deposited layer. By further increasing the reverse pulse current density from 2 A dm−2 to 6 A dm−2, void defects can be completely eliminated and even void-free deposition of high aspect ratio microcolumns (5:1) can be achieved.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42366436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An improved dissipative particle dynamics method for the liquid-particle two-phase flow in microchannels","authors":"Hua Dong, Xu Wu, Liang-Liang Fan, Liang Zhao","doi":"10.1088/1361-6439/acee88","DOIUrl":"https://doi.org/10.1088/1361-6439/acee88","url":null,"abstract":"Liquid-particle two-phase flow in microchannel widely exists in the fields of biomedical and environmental monitoring, such as the lab-chip device for disease diagnosis. The standard dissipative particle dynamics (DPD) method has been previously employed to study the liquid-particle two-phase flow in microchannel, but it cannot accurately simulate the real process because of the unsuitable DPD parameters. In the present study, an improved DPD method was developed by changing the system energy and fitting the characteristic curve between the random force coefficient and the Schmidt number. In addition, a new logarithmic relationship between the conservative force coefficient and the particle size was found. The result demonstrated that the improved DPD method enabled more accurate simulation on the liquid-particle two-phase flow in microchannels than the standard DPD method. For instance, in the simulation of particle sedimentation, the relative deviation between the value obtained by the improved DPD method and the theoretical value was less than 6% while the relative deviation was more than 20% for the standard DPD method. The simulated result of the particle migration in microchannel was in good agreement with the result obtained by Matas et al, and the relative deviation was less than 1.5%. Therefore, the improved DPD method would have great potentials in the study on the liquid-particle two-phase flow in microchannels.","PeriodicalId":16346,"journal":{"name":"Journal of Micromechanics and Microengineering","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47924880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}