Recent advances in microscale pumping technologies: a review and evaluation

Micropumping has emerged as a critical research area for many electronics and biological applications. A significant driving force underlying this research has been the integration of pumping mechanisms in micro total analysis systems and other multi-functional analysis techniques. Uses in electronics packaging and micromixing and microdosing systems have also capitalized on novel pumping concepts. The present work builds upon a number of existing reviews of micropumping strategies by focusing on the large body of micropump advances reported in the very recent literature. Critical selection criteria are included for pumps and valves to aid in determining the pumping mechanism that is most appropriate for a given application. Important limitations or incompatibilities are also addressed. Quantitative comparisons are provided in graphical and tabular forms.     

A reduced-order model of the low-voltage cascade electroosmotic micropump

In the present investigation, we have derived an efficient reduced-order model of the low-voltage cascade electroosmotic micropump. This model can be combined with the equivalent circuit model of straight microchannels to construct a complete model for a microfluidic device, which can be employed to implement modern control schemes. To demonstrate the efficiency of the reduced-order model we employ it to estimate the zeta potentials of many subchannels in the micropump cascade using velocity measurements, which is a preliminary step to the implementation of modern control schemes. It is found that a conjugate gradient procedure employing the reduced-order model estimates accurately the zeta potential variation in the subchannels, which may be caused by adhesion of biomolecules, even with noisy velocity measurements.     

形状记忆合金/硅复合膜驱动的微泵

形状记忆合金／硅复合膜驱动的微泵由一个可形变腔体和两个单向硅薄片阀组成，微驱动膜利用ＮｉＴｉ形状记忆合金薄膜相变时具有大的可回复应力和Ｓｉ衬底膜的反偏置力，产生双向往复振动，采用图形化的ＮｉＴｉ薄膜作为热诱发相变的加热电阻，有效地提高了动态响应频率。同时降低了驱动功率。通过驱动结构的优化设计。增加了驱动位移和工作寿命。微泵采用Ｓｉ表面和立体微加工工艺、金－硅共晶键合等技术制备，它的外形尺寸为６ｍｍ     

Light‐Driven Titanium‐Dioxide‐Based Reversible Microfireworks and Micromotor/Micropump Systems

Titanium dioxide (TiO₂) possesses high photocatalytic activity, which can be utilized to power the autonomous motion of microscale objects. This paper presents the first examples of TiO₂ micromotors and micropumps. UV‐induced TiO₂ reversible microfireworks phenomenon was observed and diffusiophoresis has been proposed as a possible mechanism.     

Inkjet printed micropump actuator based on piezoelectric polymers: Device performance and morphology studies

All inkjet printed piezoelectric actuators based on poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF–TrFE)) for applications as pump actuators in microfluidic lab-on-a-chip systems (LOC) are manufactured and investigated in terms of their morphology and actuator performance. Furthermore, a pump demonstrator with an all-printed P(VDF–TrFE) actuator is characterized here for the first time. The actuators are manufactured in a fully additive and flexible way by successive inkjet printing of a P(VDF–TrFE) film sandwiched between two silver electrodes on a polyethylene terephthalate (PET) substrate. Different from most current micropumps where actuator elements are fabricated separately, no additional joining step is required in the manufacturing approach employed here. Actuator performance is investigated by measurements of piezoelectric d₃₁ coefficients as well as remanent polarization P_rem for different thermal treatments of the as-printed P(VDF–TrFE) films. A strong dependence of the device performance on the annealing temperature is found with maximum values for d₃₁ and P_rem of approximately 10 pm V⁻¹ and 5.8 μC cm⁻², respectively. Morphology investigations of the printed films by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) indicate an increased degree of crystallinity of the piezoelectric β-phase for samples annealed at temperatures above 110 °C, which coincides with improved device performance. A basic pumping function with pump rates of up to 130 μL min⁻¹ is demonstrated, which is promising for future applications in LOC. Furthermore, the process chain and characterization presented here can be employed to design and manufacture also other P(VDF–TrFE)-based devices and allows the combination with additional printed on-chip functionalities in future LOC.