IEC 255 |
| William C. Trogler, Honglae Sohn, and Sarah Toal. Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr. 0358, La Jolla, CA 92093-0358 |
| Colloidal suspensions of luminescent tetraphenyl(polysiloles) and functionalized tetraphenyl(silole) monomers, which are molecular nanoaggregate analogues of solid state nanodot sensors have been prepared. The tetraphenyl(polysiloles), copolymers, and corresponding germanium derivatives have been previously shown to be excellent sensor materials for electron acceptor nitroaromatics, such as TNT. Detection at ppt levels is achieved by quenching of the intense green luminescence of these materials by electron transfer to analyte. The hydrophobic nature of polysiloles precludes detection of ionic oxidants, such as chromate, which have no affinity for these hydrophobic materials. Colloidal suspensions of these polymers display increased sensitivity toward chromate; however, nitrate and perchlorate show only a weak quenching ability. The detection sensitivity can be enhanced to determine subppm levels of analyte by addition of surface ionizable groups, such as amines. Even arsenate, another drinking water contaminant of great concern, can be detected by this approach. Surface modification, which yields stable colloid suspensions, as well as AFM and SEM characterization of particle sizes (< 120 nm) will be presented. |
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Nanotechnology and the Environment
1:30 PM-5:15 PM, Thursday, March 27, 2003 Convention Center -- Room 392, Oral
Division of Industrial and Engineering Chemistry |