Biomimetic, low power pumps based on soft actuators

A new biomimetic miniaturized pump based on soft materials is reported. The pump consists of a soft chamber made of polyurethane or polydimethyl siloxane (PDMS) tubes and a set of two soft electro-mechanical actuators in a cantilever configuration. The soft actuators were constructed using Nafion as an ionic polymer and polypyrrole as conducting material to make the electrodes by chemical in situ polymerisation. To our knowledge this is the first time this type of actuator has been reported. This choice of electrode material permits the pump to be actuated using lower potentials than when using platinum (+/- 3 V as opposed to +/- 5 V when electroding using platinum). This leads to a much lower power consumption, which averaged to approximately 69 mW per stroke for an actuator that measured 3 cm length by 0.3 cm wide (as opposed to 227 mW when electroding with platinum). As the potential steps are applied to the actuators, they bend and produce a change of volume in the soft pumping chamber that generates the flow movement. The pumps developed in the present work were capable of flow rates of up to 1.6 mu L/s, and could cope with backpressures of up to 0.025 Bar. This biomimetic pump is suitable for long term field deployable platforms, such as reagent based analytical platforms, since it is low power, corrosion resistant and also resistant to particle ingress due to its soft nature. (c) 2006 Elsevier B.V. All rights reserved.