一种以毛细作用和蒸发为驱动力的新型微泵的研制

关于微泵的研制起始于20世纪80年代^[1],现已研制开发出很多种类的微泵,如可以用多种驱动力驱动的机械微泵(压电驱动、静电驱动和热气动力驱动等)^[2]和以场感应流微泵为主的非机械微泵(包括电渗泵、磁液态动力泵和电液态动力泵等^[3]).机械微泵的制造工艺复杂,而且液流有脉动性;场感应流微泵的液流无脉动性,流速范围可在每分钟几纳升到每分钟几百微升之间变化,因此被微流控系统广泛采用,但这种微泵需要庞大的驱动器,使用不便.     

两种填充型双电渗泵的制作与流量控制

自制了同柱双电渗泵和异柱双电渗泵，考察了这两种填充型双电渗泵的泵流速及流量与驱动电压的关系，并将其与填充型单电渗泵进行了比较，说明了其优势。     

一种移动化学反应界面的实验装置

描述了一种移动化学反应界面的实验装置，这一装置备有二台恒流泵用于连续性地驱动阴极液和阳极液，备有二根连接于计录仪的电极用于测定反应管两端的电压。用０．００５ｍｏｌ．Ｌ＾－１ＣｏＣｌ２和０．０１ｍｏｌ．Ｌ＾－１ＮａＯＨ（同时含有０．１ｍｏｌ．Ｌ＾－１背景电解质（ＫＣｌ）形成的移动化学反应界面实验了这一装置。结果表明：（１）能很好地避免电解时产生的氢离子和氢氧根离子的干扰；（２）在单根凝胶柱上可进行多     

微流体驱动与控制技术*

在微流控系统所需的功能单元中,微流体驱动与控制操作单元尤为重要。微系统条件下,表面张力的影响变得十分明显,在工程意义上,常规的流体体积流动的驱动方法在微管道中往往效果不好甚至是不可行的。本文简要评述了用于微流体驱动的机械微型泵技术,基于电、光、磁等的非机械微型泵技术,以及微流体的高效混合控制等技术的研究现状,对微流体驱动与控制的未来作了展望。     

电动泵技术研究进展

电液动力学（EHD）研究的是在流体上施加电场后流体的流动。在微分析系统中,EHD的主要应用是电动泵（EKP）技术即电泳泵和电渗泵两个主要泵技术。这些独特的泵技术被广泛应用在推动极小截面的管道中化学和生物流体流动,管道尺寸从平方毫米到平方微米量级,甚至纳米通道量级。近年来,电渗泵出现了填充床、整体柱、平行多通道、纳米通道和微孔膜等各种新的形式,显示了其在微分析系统中的集成化和在毛细管液相色谱、流动注射分析和药物输送等应用研究中的潜力。本文对电动泵技术进行评述。     

一种移动化学反应界面的实验装置(英文)

描述了一种移动化学反应界面的实验装置．这一装置备有二台恒流泵用于连续性地驱动阴极液和阳极液，备有二根连接于计录仪的电极用于测定反应管两端的电压．用0．005mol·L-1CoCl_2和0.01mol·L－1NaOH（同时含有0．1mol·L－1背景电解质KCl）形成的移动化学反应界面实验了这一装置．结果表明：（1）能很好地避免电解时产生的氢离子和氢氧根离子的干扰；（2）在单根凝胶柱上可进行多次移动化学反应界面实验；（3）不论是在实验进行中还是在实验后都能很方便地测定沉淀区带的长度；（4）能节省大量的阴极液和阳极液；（5）具有较好的稳定性．     

我国首台国产LC-TOFMS在上海通过验收

不久前，上海精密科学仪器有限公司、复旦大学承担的上海市科委的攻关项目“微流高压梯度泵毛细管高效液相色谱一电喷雾飞行时间质谱（LC-TOFMS）联用仪（031409004）”进行了项目验收。     

电渗泵在顺序注射萃取法测定酚中的应用

电渗泵是一种液流驱动泵，具有装置简单、载流无脉动、流量范围大和驱动电压适中等优点。用含1mmol/L三乙醇胺和0.1mmol/L四丁基溴化铵的乙醇溶液作泵载流，采用顺序注射萃取-分光光度法，对水样挥发酚进行了测定。有机载流可避免产生界面，减小检测干扰。载流添加剂可提高泵流量，改善流量稳定性。另外，还研究了酚的各种萃取条件。水中酚的检出限为7цg/L(3a，n=11)；回收率为92%-94%。方法证明了电动流动分析系统可用于溶剂萃取和有机分析。     

电渗泵中电渗流的控制

电渗泵是利用载流的电渗驱动原理，结合电色谱(EC)、毛细管电泳(CE)、液相色谱柱技术制作的输液微泵，是新颖的流体和样品输送技术。电渗泵中电渗流(EOF)控制方法与EC和CE等文献中的电渗流控制方法是相同的。本文对EC和CE等文献中有关EOF控制方法作了总结，并对电渗泵的研究现状和应用作一些前瞻分析。     

组合离子膜微电色谱方法

驱动电压低，无气泡产生，稳定性好，控制方便，成本低的组合离子膜微电色谱方法。技术特点：选取通道Ⅰ，将长条形阳离子交换膜（1）封装于通道Ⅰ内，阳离子交换膜（1）两端外露于通道Ⅰ两端，通道Ⅰ一端封接液流输出用毛细管（7），阳离子交换膜（1）一端位于毛细管（7）内，通道Ⅰ另一端置于容装正极电解液的正极池（5），在正极池内插置与驱动电源正极端连接的正极柱（3）；     

Surface micromachined electrostatically actuated micro peristaltic pump

An electrostatically actuated micro peristaltic pump is reported. The micro pump is entirely surface micromachined using a multilayer parylene technology. Taking advantage of the multilayer technology, the micro pump design enables the pumped fluid to be isolated from the electric field. Electrostatic actuation of the parylene membrane using both DC and AC voltages was demonstrated and applied to fluid pumping based on a 3-phase peristaltic sequence. A maximum flow rate of 1.7 nL min(-1) and an estimated pumping pressure of 1.6 kPa were achieved at 20 Hz phase frequency. A dynamic analysis was also performed with a lumped-parameter model for the peristaltic pump. The analysis results allow a quantitative understanding of the peristaltic pumping operation, and correctly predict the trends exhibited by the experimental data. The small footprint of the micro pump is well suited for large-scale integration of microfluidics. Moreover, because the same platform technology has also been used to fabricate other devices (e.g. valves, electrospray ionization nozzles, filters and flow sensors), the integration of these different devices can potentially lead to versatile and functional micro total analysis systems (microTAS).     

Concepts for a new class of all-polymer micropumps

This paper presents a polymer-based micropump addressing the cost, performance, and system compatibility issues that have limited the integration of on-chip micropumps into microanalysis systems. This pump uses dielectric elastomer actuation to periodically displace fluid, and a pair of elastomeric check valves to rectify the fluid's resulting movement. Its significant features include the use of a transparent substrate, self-priming capability, insensitivity to gas bubbles, and the ability to admit particles. A pump occupying less than 10 mm2 of chip space produced a 77 microl min(-1) flow rate. The pump has a high thermodynamic efficiency and exhibits little performance degradation over 10 hours of operation. In addition to its notable performance, the pump can be fabricated at low cost and directly integrated into microfluidic chips that use planar softlithography-formed structures. The new pump concept, fabrication, and experimental performance are discussed herein.     

Design of valveless type piezoelectric pump for micro-fluid devices

The operation principle of travelling wave rotary type ultrasonic motor can be applied to fluidic transfer mechanism of micro-pump successfully. In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of travelling wave as a volume transporting means. The proposed pump is consisted of coaxial cylindrical shells that joined piezoelectric ceramic ring and metal body respectively. To confirm the actuation mechanism of proposed pump model, a numerical simulation analysis on the proposed model was implemented. In accordance with the variation of exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics if proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was about 580[μl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. We confirmed that peristaltic motion of piezoelectric actuator was able to be applied to the fluid transferring mechanism of valveless type micro pump effectively through this research.     

Designing tubular conducting polymer actuators for wireless electropumping

Rational design and shaping of soft smart materials offer potential applications that cannot be addressed with rigid systems. In particular, electroresponsive elastic materials are well-suited for developing original active devices, such as pumps and actuators. However, applying the electric stimulus requires usually a physical connection between the active part and a power supply. Here we report about the design of an electromechanical system based on conducting polymers, enabling the actuation of a wireless microfluidic pump. Using the electric field-induced asymmetric polarization of miniaturized polypyrrole tubes, it is possible to trigger simultaneously site-specific chemical reactions, leading to shrinking and swelling in aqueous solution without any physical connection to a power source. The complementary electrochemical reactions occurring at the opposite extremities of the tube result in a differential change of its diameter. In turn, this electromechanical deformation allows inducing highly controlled fluid dynamics. The performance of such a remotely triggered electrochemically active soft pump can be fine-tuned by optimizing the wall thickness, length and inner diameter of the material. The efficient and fast actuation of the polymer pump opens up new opportunities for actuators in the field of fluidic or microfluidic devices, such as controlled drug release, artificial organs and bioinspired actuators.

Tubular conducting polymer actuators are used for developing a wireless electropumping device. Bipolar electrochemistry, allowing symmetry breaking in terms of polarization and electrochemical reactions, is the key ingredient for efficient pumping.     

Hand-held syringe as a portable plastic pump for on-chip continuous-flow PCR: miniaturization of sample injection device

On-chip continuous-flow polymerase chain reactions (PCRs) generally require peripheral apparatus such as a pump for injecting a sample liquid into the fluidic channel. This makes the overall instrumentation bulky, limiting integration. In this study, we propose a new scheme for injecting a sample employing a hand-held syringe as a portable plastic pump, and apply it to an on-chip continuous-flow PCR. In the proposed injection scheme, sample actuation was realized inside a highly gas-permeable and blunt-ended fluidic conduit connected to a hand-held plastic syringe filled with compressed air. In this system, the degree of air diffusion via the walls of the gas-permeable conduit becomes greater in the anterior (closer to the outlet) end of the sample plug than the posterior (closer to the inlet) end, because a relatively larger quantity of air is retained inside the syringe at the posterior end of the sample plug. This creates a pressure gradient at the inlet and outlet of the fluidic conduit and propels the sample forward toward the outlet. Preliminary experiments were performed for the quantitative analyses and evaluation of the proposed sample injection scheme using gas-permeable silicone tubes. As practical applications, a 230 bp gene fragment from a plasmid vector and the first 282 bp of the interferon-beta (IFN-β) promoter from a human genomic DNA were successfully amplified on a microdevice coupled with a hand-held syringe as a portable sample actuation device, greatly enhancing device portability for on-site analyses.     

Elastomer-glass micropump employing active throttles

We report a reciprocating microfluidic pump, the Micro Throttle Pump (MTP), constructed in a relatively uncomplicated manner from glass and microstructured poly(dimethylsiloxane)(PDMS). Unconventionally, the MTP employs throttling of fluid flow as distinct from fully-closing valve structures. Accordingly, this technique offers the prospect of solid-phase suspension tolerance. The reported MTP employs piezoelectrically (PZT) actuated deformation of flow constrictions (throttles) fabricated from PDMS at the two ports of a central, PZT actuated pump chamber. By appropriate time-sequencing of the individual PZTs' actuation, pumping can be induced in either direction. PDMS' elasticity further facilitates throttle operation by virtue of allowing significant PZT flexure that is substantially independent of the underlying PDMS microstructure. In contrast, in a rigid substrate such as silicon, deformation is constrained to where underlying microstructured cavities exist and this restricts design options. We describe the construction and performance of a prototype MTP capable of pumping 300 microl min(-1) or alternatively generating a back-pressure of 5.5 kPa. Preliminary modelling of MTP operation is also presented.     

Characterisation of torsional actuation in highly twisted yarns and fibres

Highly twisted oriented polymer fibres and carbon nanotube yarns show large scale torsional actuation from volume expansion that can be induced, for example, thermally or by electrochemical charging. When formed into spring-like coils, the torsional actuation within the fibre or yarn generates powerful tensile actuation per muscle weight. For further development of these coil actuators and for the practical application of torsional actuators, it is important to standardise methods for characterising both the torsional stroke (rotation) and torque generated. By analogy with tensile actuators, we here introduce a method to measure both the free stroke and blocked torque in a one-end-tethered fibre. In addition, the torsional actuation can be measured when operating against an externally applied torque (isotonic) and actuation against a return spring fibre (variable torque). A theoretical treatment of torsional actuation was formulated using torsion mechanics and evaluated using a commercially available highly-oriented polyamide fibre. Good agreement between experimental measurements and calculated values was obtained. The analysis allows the prediction of torsional stroke under any external loading condition based on the fundamental characteristics of the actuator: free stroke and stiffness.     

High actuation performance offered by simple diene rubbers

Dielectric elastomers are materials well known for their superior actuation behavior under applied electric field. The simplicity of material fabrication and clear working principle of dielectric elastomer actuators (DEAs) can offer various applications of dielectric elastomers. In this work, we have compared a number of different types of commercially available elastomers in terms of actuation performance. It was found that well‐known commercial rubbers like acrylonitrile‐butadiene rubbers (NBR) can offer higher actuation performance in DEAs than the frequently used dielectric elastomers, such as acrylic rubber and silicone. The acrylonitrile content of the NBR was found to play an important role in the dielectric and consequently actuation properties. More interestingly, we observed that addition of organic oil, such as dioctyl adipate, can greatly enhance the actuation performance. Copyright © 2016 John Wiley & Sons, Ltd.     

All-electronic droplet generation on-chip with real-time feedback control for EWOD digital microfluidics

Electrowetting-on-dielectric (EWOD) actuation enables digital (or droplet) microfluidics where small packets of liquids are manipulated on a two-dimensional surface. Due to its mechanical simplicity and low energy consumption, EWOD holds particular promise for portable systems. To improve volume precision of the droplets, which is desired for quantitative applications such as biochemical assays, existing practices would require near-perfect device fabrication and operation conditions unless the droplets are generated under feedback control by an extra pump setup off of the chip. In this paper, we develop an all-electronic (i.e., no ancillary pumping) real-time feedback control of on-chip droplet generation. A fast voltage modulation, capacitance sensing, and discrete-time PID feedback controller are integrated on the operating electronic board. A significant improvement is obtained in the droplet volume uniformity, compared with an open loop control as well as the previous feedback control employing an external pump. Furthermore, this new capability empowers users to prescribe the droplet volume even below the previously considered minimum, allowing, for example, 1 : x (x < 1) mixing, in comparison to the previously considered n : m mixing (i.e., n and m unit droplets).     

Electrical actuation of dielectric droplets by negative liquid dielectrophoresis

This paper presents an electrical actuation scheme of dielectric droplet by negative liquid dielectrophoresis. A general model of lumped parameter electromechanics for evaluating the electromechanical force acting on the droplets is established. The model reveals the influence of actuation voltage, device geometry, and dielectric parameter on the actuation force for both conductive and dielectric medium. Using this model, we compare the actuation forces for four liquid combinations in the parallel-plate geometry and predict the low voltage actuation of dielectric droplets by negative dielectrophoresis. Parallel experimental results demonstrate such electric actuation of dielectric droplets, including droplet transport, splitting, merging, and dispending. All these dielectric droplet manipulations are achieved at voltages < 100 V_rms. The frequency dependence of droplet actuation velocity in aqueous solution is discussed and the existence of surfactant molecules is believed to play an important role by realigning with the AC electric field. Finally, we present coplanar manipulation of oil and water droplets and formation of oil-in-water emulsion droplet by applying the same low voltage.