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

• Demonstration of voltage-controlled liquid flow through a macroporous silicon membrane. • Three-dimensional fluidic channel array based on a macroporous silicon membrane. • Dynamic liquid flow control using polypyrrole-based electrochemical wetting change. 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 (SnO 2) 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. [ABSTRACT FROM AUTHOR]