Person:

Hamedi, Mahiar Max

The fields of paper microfluidics and printed electronics have developed independently, and are incompatible in many of their aspects (e.g. printed electronic thin films are not designed to tolerate the flows of liquids, and especially of water, nor are water filled-channels designed to conduct electrons). This work demonstrates monolithic integration of microfluidics and electronics on paper, by extending the use of paper microfluidics to the fabrication of electrical conductors by the wicking of aqueous conducting inks inside microfluidic channels. These conductors are unique in that they can act as wires, electrodes, and microfluidic channels at the same time. These techniques, make it possible to print both two- and three-dimensional fluidic, electrofluidic, and electrical components using simple methods, and thus to design new paper devices. This paper demonstrates the fabrication of three classes of devices: i) 3D paper “printed circuit boards”, ii) vertical-flow electroanalytical devices, and iii) foldable, all-organic paper batteries.

This work describes the adaptive use of conventional stainless steel pins—used in unmodified form or coated with carbon paste—as working, counter, and quasi-reference electrodes in electrochemical devices fabricated using cotton thread or embossed omniphobic RF paper to contain the electrolyte and sample. For some applications, these pin electrodes may be easier to modify and use than printed electrodes, and their position and orientation can be changed as needed. Electroanalytical devices capable of multiplex analysis (thread-based arrays or 96-well plates) were easily fabricated using pins as electrodes in either thread or omniphobic RF paper.