Active liquid flow control through a polypyrrole-coated macroporous silicon membrane toward chemical stimulation applications

In this paper, we demonstrate the voltage-controlled flow of organic liquid through a macroporous silicon structure. The demonstrated flow control structure consists of a silicon-based macropore membrane and flow control units formed on polypyrrole (PPy)-coated pores, which are actuated by its electrochemical wetting change. Conformal coating of a PPy layer along macropore silicon walls is achieved with the help of spray-deposited tin-oxide (SnO2) layer on the pores. The transport of organic liquid through the developed membrane is successfully controlled by low-voltage external bias on the PPy layer. Cyclic deliveries of organic liquid were demonstrated using the proposed concept. Considering the highly ordered fluidic channel structure formed in silicon, which can have multiple separated electrodes, the proposed concept has the potential to achieve an actuated fluidic dispenser in an arrayed form. (C) 2020 Elsevier B.V. All rights reserved.