Date of Award

Fall 12-16-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Michael D. Williams, Ph.D.

Second Advisor

James Reed, Ph.D.

Third Advisor

Ishrat Khan, Ph.D.

Abstract

Conducting polymers have emerged as a promising material for optoelectronics and chemical sensing application. Polyaniline (PANI) is a conductive polymer which can be easily functionalized to be specific for various biomolecules and has ideal sensor characteristics. The protonation and deprotonation of the polyaniline’s backbone by derivatization can result in color and conductive change responses. This makes it ideal for the construction of a real time, naked eye sensor. Derivatized polyaniline has previously been reported as a colorimetric sensor in solution. We plan to create a more practical sensor by synthesizing hydroxyl functionalized polyaniline thin films. In this study, we designed a process to functionalize polyaniline and deposit it as a thin film on quartz or silicon substrate via a dip coating process. To demonstrate the use of derivatized PANI in biosensing applications, derivatized and underivatized PANI thin films were treated with solutions of L-aspartic (Asp) acid at concentrations ranging from 10-8 mM to 103 mM and monitored utilizing UV-Vis spectroscopy. We found that the derivatized thin films change from deep blue to green color upon addition of Asp solution and showed a decrease in the characteristic quinoid ring peak at 600nm and the appearance of a new polaron peak at 425nm. The underivatized PANI films showed no colorimetric response indicating the hydroxyl functionalized PANI films are a more ideal material for a biosensing and naked eye detection. The polyaniline derivative was characterized using FT-IR spectroscopy, 1H NMR spectroscopy, UV-VIS spectroscopy, and Scanning Electron Microscopy. Additionally, conductivity studies were utilized to explore the material’s effectiveness as an electronic sensor using a 4-point probe to measure resistance.

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