I. Surface derivatization of glassy carbon. II. Formation and characterization of charge transfer complexes in molecular sieve hosts

Kathleen Jae Hoekstra, Purdue University

Abstract

Glassy carbon surfaces were modified with several alkylamines in the interest of creating stable chemical bonding to a substrate inert to corrosive aqueous environments at moderately elevated temperatures. The influence of the aliphatic chain length upon film coverage and upon the ability of the film to insulate the interface from aqueous agents were analyzed with variable angle XPS, wettability, voltammetry, and ellipsometry. Film thickness measurements and cyclic voltammetry studies established the integrity of longer alkylamine films, and thereby protection of the carbon-nitrogen bonding at the interface, to be maintained in corrosive aqueous environments. The susceptibility of graphitic edge plane sites of the glassy carbon surface to oxidation provides a route to manipulation of chemical functionalities and further reactivity at the glassy carbon interface. Phosphate species were formed at the bare carbon surface, at a pretreated carbon surface, or at a surface modified with an alkanolamine, by phosphorylation of OH species or other oxidic surface sites. These modified surfaces served as a foundation for deposition of zirconium-bis(phosphonic acid) multilayer films. Synthesis of conductive materials with controlled dimensionality and molecular architecture may provide one approach toward realizing the development of anisotropic electronic conductors at the nanoscale. Charge transfer complexes of TTF-TCNQ, of triethylamine and of DABCO with TCNQ, and of halides with TTF, were synthesized within insulating zeolite Y hosts and mesoporous, MCM-41 channels. Also, an analogue of the triethylamine salt of TCNQ was anchored to the MCM channel wall. Finally, the influence of host acidity and of Cu(II) ions in zeolite Y upon encapsulated TTF was explored. The encapsulation of guests and formation of reaction products in the host was followed with spectroscopic (IR, VIS, ESR) and physical characterizations (TGA, XRD, nitrogen sorption, microwave conductivity).

Degree

Ph.D.

Advisors

Bein, Purdue University.

Subject Area

Chemistry|Chemistry

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