Functionalized poly(p-phenylene ethynylene)s for chemical sensing and carbon nanotube (CNT) dispersion

Pourghaz, Yousef (2011) Functionalized poly(p-phenylene ethynylene)s for chemical sensing and carbon nanotube (CNT) dispersion. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (38MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

This dissertation explores the design, synthesis, characterization and applications of conjugated polymers as fluorescence "turn-on" chemosensors and carbon nanotube (CNT) dispersants. A series of poly(p-phenylene ethynylene)s (PPEs) were synthesized using the Sonogashira cross coupling reaction and "click chemistry" was applied to introduce receptor groups such as amino groups to the side chain of the polymers. The ability of synthesized polymers to detect metal ions through a fluorescence "turn-on" mechanism was tested using various metal ions with UV-Vis and fluorescence spectroscopic techniques. The receptor was also introduced to the backbone of the water-soluble polymer to study the efficiency of the polymer in aqueous media. To investigate the binding stoichiometry between the polymer and a metal ion, a ¹H NMR titration experiment was conducted to obtain a "Job plot". Further evidence for the stoichiometry ratio was provided by applying UV-Vis titration data to the "SPECFIT" analysis software. Click chemistry was also used to functionalize the PPEs with electron-rich groups such as anthracene and pyrene to interact with CNTs. The difficulties in working with click-produced monomers and synthesized polymers are discussed in terms of low solubility in organic solvents. An alternative synthetic approach to overcome the solubility problem is also described in chapter 3.

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