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Date Permissions Signed

5-10-2013

Date of Award

2013

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Murphy, Amanda R.

Second Advisor

Leger, Janelle

Third Advisor

Rider, David A. (Materials scientist)

Abstract

In order to produce conductive, biocompatible and mechanically robust materials for use in bioelectrical applications, we have developed a new strategy to selectively incorporate poly(pyrrole) (Ppy) into constructs made from silk fibroin. Here, we demonstrate that covalent attachment of negatively charged, hydrophilic sulfonic acid groups to the silk protein can selectively promote pyrrole absorption and polymerization within the modified films to form a conductive, interpenetrating network of Ppy and silk that is incapable of delamination. To further increase the conductivity and long-term stability of the Ppy network, a variety of small molecule sulfonic acid dopants were utilized and the properties of these silk-conducting polymer composites were monitored over time. The composites were evaluated using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), optical microscopy, energy dispersive X-ray (EDX) spectroscopy, cyclic voltammetry, 4-point resistivity probe and mechanical testing. In addition, the performance was evaluated following exposure to several biologically relevant enzymes. Using this strategy, we are able to produce mechanically robust polymer electrodes in a variety of geometries with stable electrochemical performance and sheet resistivities on the order of 102 Ω/sq (conductivity ~1 S/cm). We adapted anisotropic versions of our silk-Ppy composites to construct electrically-controlled actuators that exhibit repeated bending movements under applied currents less than 5 mA, and potentials between 1 and 4 V. These bilayer actuators function through anion exchange in biologically-relevant electrolytes, and show promise for fully biocompatible actuator systems.

Type

Text

DOI

https://doi.org/10.25710/wmvq-fp12

Publisher

Western Washington University

OCLC Number

843779895

Subject – LCSH

Tissue engineering; Silk; Conducting polymers; Biomedical materials

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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