New materials for optical sensing of explosives copolymers containing 2-vinyl-4,6-diamino-1,3,5-triazine and co-crystals of electron rich aromatic molecules and 1,3-dinitrobenzene

This dissertation focuses on the development of electron rich polymers with an affinity for nitroaromatics. Thin polymer films of the electron rich polymers could be applied in an optical waveguide sensor to detect nitroaromatics by changes in the optical properties of the polymer thin films. Charge transfer complexes between electron rich aromatic reagents and electron deficient nitroaromatics were produced providing an understanding of the intermolecular interactions between the electron donor and electron acceptor. Electron rich copolymers were synthesized with 2-vinyl-4,6-diamino-1,3,5-triazine (VDAT) using a published literature procedure. The polymerization procedure was extended to a variety of electron rich monomers, resulting in the production of a number of electron rich copolymers. Thin films of the copolymers were spin coated and their optical properties were characterized by spectroscopic ellipsometry before and after exposure to a nitroaromatic vapor. The exposure to the nitroaromatic vapor allowed the formation of complexes with the electron rich copolymers and the nitroaromatic molecules, creating a change in the optical properties of the polymer films. This refractive index change after exposure to a nitroaromatic demonstrated the possibility of these films to be applied in an optical waveguide sensor for explosive detection. Co-crystals were grown between electron rich donors and the electron deficient 1,3-dinitrobenzene by the slow evaporation method. When the electron donor solution and electron acceptor solution were combined in a crystallization dish, significant color changes were observed. The interaction between the electron donor and electron acceptor were characterized using analytical techniques. (Published By University of Alabama Libraries