This paper briefly reviews recent research and developments of micropump designs with a particular emphasis on mechanical micropumps and summarizes their applications in biomedical fields. A comprehensive description of the actuation schemes, flow directing concepts and liquid chamber configurations for micro pumping is provided with illustrative diagrams. Then, a comparative study of current mechanical micropump designs highlighting their advantages and limitations for various applications is presented, based on performance criteria such as actuation voltage and power consumption, ranges of operating frequency and maximum flow rate and backpressure. This study compiles and provides some basic guidelines for selection of the actuation schemes and flow rate requirements in biomedical applications. Different micropumps in biomedical applications, such as blood transport and drug delivery also have been reviewed.

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The dynamic mechanical behavior of uncrosslinked (thermoplastic) and crosslinked (thermosetting) acrylonitrile butadiene rubber/poly(ethylene-co-vinyl acetate) (NBR/EVA) blends was studied with reference to the effect of blend ratio, crosslinking systems, frequency, and temperature. Different crosslinked systems were prepared using peroxide (DCP), sulfur, and mixed crosslink systems. The glass-transition behavior of the blends was affected by the blend ratio, the nature of crosslinking, and frequency. sThe damping properties of the blends increased with NBR content. The variations in tan ␦ max were in accordance with morphology changes in the blends. From tan ␦ values of peroxide-cured NBR, EVA, and blends the crosslinking effect of DCP was more predominant in NBR. The morphology of the uncrosslinked blends was examined using scanning electron and optical microscopes. Cocontinuous morphology was observed between 40 and 60 wt % of NBR. The particle size distribution curve of the blends was also drawn. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends, and it decreased with an increase in the NBR content. Various theoretical models were used to predict the modulus of the blends. From wide-angle X-ray scattering studies, the degree of crystallinity of the blends decreased with an increasing NBR content. The thermal behavior of the uncrosslinked and crosslinked systems of NBR/EVA blends was analyzed using a differential scanning calorimeter.

A microfluidic control device that uses an electroactive polymer for actuation has been recently proposed. This design has potential to control temperature sensitive particle-laden liquids. The electro-mechanical characteristics of ionic polymer metal composite (IPMC) actuators have been studied both theoretically and empirically. However, very little data has been published on the thermal behavior of IPMC actuators. To realize the proposed fluidic control device, it is essential to understand the thermal properties of the device under actuation conditions. This paper discusses the theoretical basis for developing a multiphysics model describing electroactive polymer actuation. In addition, experimental results are presented that give insight to the thermal characteristics of IPMC actuation.