Low-voltage manipulation of an aqueous droplet in a microchannel via tunable wetting on PPy(DBS)

Abstract

This paper presents experimental results and analyses on the controlled manipulation of a liquid droplet. The droplet was manipulated upon local reduction and oxidation (redox) of dodecylbenzenesulfonate doped polypyrrole (PPy(DBS)) in an immiscible organic fluid of bulk dichloromethane (DCM, CH₂Cl₂). The electrochemically tunable wetting property of PPy(DBS) permitted liquid droplet manipulation at very low voltages (−1.5 V to 0.6 V). In particular, the actuation behavior of a salt water droplet upon redox of PPy(DBS) in a microchannel configuration was characterized and analyzed. The controlled lateral transport of the droplet was successfully demonstrated in a slightly tilted microchannel configuration.