Effect of inorganic acid dopants on selected molecular properties affecting electrical conductivity of poly (2,5- xylidine)

Date

4-2006

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ernesto J Del Rosario

Co-adviser

Jelynne P. Tamayo

Abstract

Computational studies using the semi-empirical (PM3) method was done for geometry optimization and single point calculation of poly(2,5-xylidine) (PXy) using HyperChem software. Selected molecular properties affecting the electrical conductivity of PXy upon doping were determined with counterions supplied by HCI, HNO3 and HCI04. Doping of PXy reduced the HOMO and LUMO energies and energy gap, and increased the conduction bandwidth and mean polarizability, as well as the total dipole moment. Doping increased the conductivity of the polymer. PXy-ES-I exhibited the highest conductivity for the doped states. The effect of increasing the degree of polymerization of PXy was also studied. The presence of methyl groups of PXy in comparison with PAni resulted in greater polymer coiling, increased stability of the polymer and lower conductivity. For experimental studies, the emeraldine base of PXy and the four emeraldine salts of PXy were synthesized by oxidative polymerization with acidification using inorganic acid dopants and ammonium peroxydisulfate as oxidant. Using a two-point probe set-up, the measured resistance showed higher conductivity for the doped forms. Among the four doped polymers, PXy-ES-C104 was found to be the most conductive. The presence of amines and other key groups in the polymer, as well as some of the dopant ions, were confirmed by infrared spectroscopy,

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2006 C4 M37

Document Type

Thesis

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