Plasticizer-free optode membranes for dissolved amines based on copolymers from alkyl methacrylates and the fluoro reactand ETHT 4014

A new class of fluorogenic copolymers has been synthesized that reversibly interacts with dissolved aliphatic amines resulting in a change in fluorescence, The copolymers are composed of different methacrylate monomeric units, such as hexyl methacrylate and the dye monomer 4-[N,N-bis(11-methacroyloyloxyundecyl)amino]-4'-trifluoro-acetylstilbene (ETHT 4014). Upon exposure to aqueous amine solutions, thin layers of the copolymers show a decrease in fluorescence at a wavelength around 520 nm and an increase in fluorescence at around 420 nn, The change in fluorescence- is based on the nucleophilic addition of amines to the trifluoroacetyl group of the reactand, thus causing a change in the degree of electron delocalization, Since the sensor layers are composed of copolymerized components, they exhibit superior optional stability to sensors based on plasticized PVC, and their lack of plasticizers enhances the shelf lifetime.