Mechanistic Study of Ion Diffusion in Fully Biocompatible Actuators Based on Silk/Polypyrrole Biocomposites
EMSL Project ID
48264
Abstract
Recently, we have developed synthetic methods to construct composites of silk and poly(pyrrole) (PPy), and have demonstrated that these films can function as actuators in aqueous electrolytes.1,2 This is among the first demonstrations of a fully biocompatible, metal-free actuator operated in a biologically relevant environment. During actuation, the silk-PPy composites contract under reduction and expand under oxidation, suggesting that the bilayer films operate primarily by anion exchange, in contrast with conducting polymer (CP) actuators based on a standard architecture, that are thought to primarily exchange cations.3-6 However, there is little direct evidence for ion diffusion through CP actuator films, and details regarding the ultimate ion profiles in working films do not exist. We therefore aim to use ToF-SIMS to study the ion penetration in our bio-composite films at various stages of electrochemical switching, including the depth of penetration and the identity of the ions being incorporated. We also plan to compare these results with devices based on a standard actuator material in order to understand how specifically the IPN structure impacts ion diffusion. We also hope to gain an understanding of how such factors as operating voltage, current passed, and number of cycles impacts the diffusion and/or retention of ions in the film.
Project Details
Project type
Limited Scope
Start Date
2014-03-11
End Date
2014-05-11
Status
Closed
Released Data Link
Team
Principal Investigator