Undergraduate Research Center

Posters at the Capitol 2010


Department of Chemistry
Middle Tennessee State University, Murfreesboro, TN
Faculty Mentor: Dr. Andrienne Friedli

The Design and Characterization of a Multilayer Structure to Act as a Surface Electromagnetic Wave Gas Sensor

Surface electromagnetic waves (SEWs) at the air/film interface of photonic band gap multilayer (PBGM) materials composed of alternating SiO2 / TiO2 dielectric layers are the basis for detection in an optical sensor that is highly sensitive to materials bound to the PBGM surface. Amine- and epoxy-substituted organosiloxane thin film interfaces have provided reactive surfaces for the attachment of proteins to PBGMs for an effective biosensor. In order to extend the detection method to gas sensing, we are exploring the use of organically-modified silicate (ormosil) films containing templated nanocavities as the basic recognition unit. When the PBGMs are coated with a 0.5-0.8 m layer of organosiloxane polymer or templated ormosil, the sensitivity to adsorbed gas molecules within the films is computationally predicted to be high. UV calibration curves allow quantification of the amount of 2,4-dinitrotoluene (DNT) template, a model for the explosive 2,4,6-trinitrotoluene (TNT), that is present in the films before and after template extraction and following exposure to DNT vapor. In this presentation, preliminary values for sensitivity of SEWs in PBGMs to trace DNT entrapped in polymeric and ormosil films are compared with sensitivities reported using other detection methods.