Journal of Polymer Science Part A: Polymer Chemistry, Vol.47, No.19, 5101-5115, 2009
Fluorescent Dendritic Polymers and Nanostructured Coatings for the Detection of Chemical Warfare Agents and Other Analytes
Polyamidoamine (PAMAM) dendrimers of generations zero (GO) to four (G4), and a hyperbranched polyurea (HB-PU), were functionalized with 1,5-dansyl (1,5-D), 2,5-dansyl (2,5-D), 2,6-dansyl (2,6-D) and nitrobenzofurazan (NBD) fluorophores that change their fluorescence emission wavelength in response to chemical environment, and the resulting dendritic polymers were characterized by MALDI-TOF mass spectrometry, H-1 NMR, C-13 NMR, and fluorescence spectroscopy. Fluorophore-functionalized dendritic polymers were then reacted further with 3-acryloxypropyldimethoxymethylsilane (AOP-DMOMS) at various fluorophore to DMOMS substitution ratios. The resulting materials were cast onto glass slides, and cured into robust nanostructured coatings. Coatings with 50% fluorophore-50% DMOMS substitution showed the strongest fluorescence and the best physical properties. Coated coupons were tested against a wide range of analytes including the chemical warfare agent simulants dimethyl methylphosphonate (DMMP) and chloroethylethylsulfide (CEES), and the water-methanol-ethanol series. It was found that the ability of the coatings to distinguish between analytes decreased with increasing cross-link density for both dendrimer and hyperbranched polymer-based coatings. It was also found that the percent fluorophore substitution and the type of dendritic polymer carrying the fluorophore bad no significant effect upon fluorescence emission wavelength, but fluorescence emission wavelength became less dependent upon solvent with increasing dendrimer generation and molecular mass. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5101-5115, 2009