In the last two decades, the vast majority of microfluidic systems have been built in poly(dimethylsiloxane) (PDMS) by soft lithography, a technique based on PDMS micromolding. A long list of key PDMS properties have contributed to the success of soft lithography: PDMS is biocompatible, elastomeric, transparent, gas-permeable, water-impermeable, fairly inexpensive, copyright-free, and rapidly prototyped with high precision using simple procedures. However, the fabrication process typically involves substantial human labor, which tends to make PDMS devices difficult to disseminate outside of research labs, and the layered molding limits the 3D complexity of the devices that can be produced. 3D-printing has recently attracted attention as a way to fabricate microfluidic systems due to its automated, assembly-free 3D fabrication, rapidly decreasing costs, and fast-improving resolution and throughput. Resins with properties approaching those of PDMS are being developed. Here we review past and recent efforts in 3D-printing of microfluidic systems. We compare the salient features of PDMS molding with those of 3D-printing and we give an overview of the critical barriers that have prevented the adoption of 3D-printing by microfluidic developers, namely resolution, throughput, and resin biocompatibility. We also evaluate the various forces that are persuading researchers to abandon PDMS molding in favor of 3D-printing in growing numbers.

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The upcoming 3D-printing revolution in microfluidics

foundations of materials science and engineering is available in our book collection an online access to it is set as public so you can download it instantly. Our books collection hosts in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the foundations of materials science and engineering is universally compatible with any devices to read.

Foundations Of Materials Science And Engineering

In 1996,210 million tons of municipal solid waste was generated in the United States. Fifty-seven million tons of this waste was recovered for recycling, 36 million tons was combusted primarily for energy recovery, and the rest (I 10 million tons) of the waste was landfilled. In 1996, plastics, rubbers, and textiles accounted for 20% by weight and 41% by volume of the total municipal solid waste. Six percent (2 million tons) of plastics, rubbers, and textiles were recovered for recycling in 1996.

Polymer-plastics technology and engineering

(57) Abstract: device for administering a drug by spraying the contents of the container (1) made of plastic material. The apparatus pair of members (23, 23 ') comprises, is supported the container (1) is in the meantime, these members (23, 23') has a first position that is not compressed to the extent that the container (1) ruptures When a relatively movable between a second position which can be members (23, 23 ') exerts sufficient pressure to discharge the contents of the container to rupture the container (1) from the discharge port.

The drug delivery device

This paper presents energy-efficient solutions for wireless sensor systems intended for the monitoring of water quality at water stations. Energy problems, such as energy scarcity and energy consumption in wireless sensor networks, are critical issues that raise concerns when it comes to defining the lifetime of a network. This can be attributed to the finite energy budget of water quality sensor nodes and also the lack of energy-efficient schemes. To address these energy problems, a detailed study has been carried out in this paper on some of the major approaches developed to address energy issues in wireless sensor systems, and dedicated to the monitoring of water quality applications in a way that contextualizes the considered solution methods. Furthermore, the solution methods are classified, while their strengths and weaknesses are also identified. Also, several suggestions are made on solution methods toward further improvement. Therefore, this paper suggests a reasonable direction for future studies on developing energy-efficient solutions in wireless sensor systems for monitoring water quality applications.

Energy Efficient Solutions in Wireless Sensor Systems for Water Quality Monitoring: A Review

Microstereolithography (MSL) is technology of fabrication of three-dimensional (3D) components by using layer-by-layer photopolymerization. Typical design goals of MSL system are: small features, high resolution, high speed of fabrication, and large overall size of component. This paper focuses on design and development of such a system to meet these optomechatronic requirements. We first analyze various optical scanning schemes used for MSL systems along with the proposed scheme via optical simulations and experiments. Next, selection criteria for various subsystems are laid down and appropriate design decisions for the proposed system are made. Further, mechanical design of the scanning mechanism is carried out to meet requirements of high speed and resolution. Finally, system integration and investigation in process parameters is carried out and fabrication of large microcomponent with high resolution is demonstrated. The proposed system would be useful for fabrication of multiple/large microcomponents with high production rate in various applications.

"on-axis" linear focused spot scanning microstereolithography system: optomechatronic design, analysis and development

Characterization of “Bulk Lithography” Process for Fabrication of Three-Dimensional Microstructures

Unconstrained depth photopolymerization is emerging as a promising technique for fabrication of several polymer microstructures such as self propagating waveguides, 3D freeform structures by bulk lithography, and polymer nanoparticles by flash exposure. Experimental observations reveal governing physics beyond Beer Lambert's law and scattering effects. This paper seeks to model unconstrained depth photopolymerization using classical nonlinear Schrodinger equation coupled with transient diffusion phenomenon. The beam propagation part of the proposed model considers scattering effects induced due to spatial variation of the refractive index as a function of the beam intensity. The critical curing energy model is used to further predict profile of polymerized voxel. Profiles of photopolymerized voxel simulated using proposed model are compared with the corresponding experimental results for several cases of exposure dose and duration. The comparison shows close match leading to conclusion that the experimentally observed deviation from Beer Lambert's law is indeed due to combined effect of diffusion of photoinitiator and scattering of light because of change in the refractive index.

On the evolution of cured voxel in bulk photopolymerization upon focused Gaussian laser exposure

Microstereolithography (MSL) has been a promising technology for fabrication of three-dimensional (3D) microstructure using layer-by-layer photopolymerization. However, this process produces 3D microstructures with a step corresponding to each layer. We propose in this paper a novel way, termed as ‘Bulk Lithography’, of generating 3D microstructures in single-pass scanning of laser beam over the photopolymer resin of unconstraint depth. In the proposed method, laser energy exposure, being one of the important parameters affecting cured depth, is varied along the line scan to enable fabrication of varying depth structure. Test structure is fabricated with proposed method to illustrate the capability of the proposed process. Lesser fabrication time and step-free 3D microfabrication in the direction perpendicular to the scan plane (z-axis) are the key features of the proposed method.Copyright © 2011 by ASME

3D Microfabrication Using Bulk Lithography

Surface texturing is a process of fabricating specific patterns on a surface to enhance surface properties such as friction, contact area, air aspiration, wear, hydrophobicity, etc. Fabricating surfaces with planned micro features is an effective method to improve tribological performance of the interacting surfaces. Laser surface texturing process is one of the best suitable processes for producing micro-patterns. Micro textures are imparted on HSS discs using CO2 laser, varying the shape and dimensions of the resulting dimples affecting the frictional coefficient and wear. Experiments have been accomplished to determine effects of textural variations such as areal density of dimples, dimple shape, area of dimples and depth of dimples on the Coefficient of Friction (COF) and Wear. Effects of lubrication conditions (Dry and Wet), pin material (MS, SS, EN31), applied load (25N, 50N, 75N) and Sliding velocity (400 rpm, 800 rpm and 1200 rpm) are evaluated on COF and Wear. Tests have been performed on pin-on-disk apparatus along guidelines of Taguchi L18 Orthogonal Array, keeping constant sliding distance of 940 m (about 10,000 cycles). Experimentally, it is found that wet lubricated, circular shaped dimples, with areal density 7.5%, dimple area 0.09 mm2 with MS material pin provides best results. This experimental analysis has been performed to test the applicability, efficiency and reliability of the textured surfaces.

Kiran Bhole

Papers

"on-axis" linear focused spot scanning microstereolithography system: optomechatronic design, analysis and development

Characterization of “Bulk Lithography” Process for Fabrication of Three-Dimensional Microstructures

On the evolution of cured voxel in bulk photopolymerization upon focused Gaussian laser exposure

3D Microfabrication Using Bulk Lithography

Design and Development of Surface Texture for Tribological Application