Conjugated Polymer Actuators

On-Chip Control of Redox

Working with Prof. Pamela Abshire’s group, we have developed an integrated potentiostat for driving redox of conjugated polymers on a chip surface. What we mean by “integrated” is that the circuitry, the counter, reference, and working electrodes, and the conjugated polymer are all on the chip. No external potentiostat is needed. A figure of the chip surface without PPy on it is shown below, as well as a figure of the chip mounted to a DIP40 package and surmounted by a circular well for holding the electrolyte. Connections to the external world are made via the legs of the DIP40, which communicate with the chip via bond wires that can be seen around the edges of the chip. The reference electrode was a pseudo-reference of Au.

Figures from S. B. Prakash, M. Urdaneta, M. Christophersen, E. Smela, and P. Abshire, "In situ electrochemical control of electroactive polymer films on a CMOS chip," Sens. Act. B, 129 (2), 699-704 (2008).

The cyclic voltammograms obtained with the chip were comparable to those obtained using an external potentiostat, and the color change of the PPy films on the working electrodes confirmed that full redox was taking place. This circuitry can be utilized for controlling the positions of the lids covering the wells in our cell-based sensors.

For further information see:

• S. B. Prakash, M. Urdaneta, M. Christophersen, E. Smela, and P. Abshire, "In situ electrochemical control of electroactive polymer films on a CMOS chip," Sens. Act. B, 129 (2), 699-704 (2008).
• S. B. Prakash, P. Abshire, M. Urdaneta, M. Christophersen, and E. Smela, "A CMOS potentiostat for control of integrated MEMS actuators," Int. Symp. Circuits & Systems (ISCAS06), Kos, Greece (May 21-24, 2006).
• E. W. H. Jager, E. Smela, and O. Inganäs, "On-chip microelectrodes for electrochemistry with moveable PPy bilayer actuators as working electrodes," Sens. Act. B, 56, 73-78 (1999).