SYNTHESIS AND CHARACTERIZATION OF NANOSCALE FLUORESCENT POLYMER FILMS

Performance of the chemical sensing devices is based sensitivity to the targeted analytes and accuracy of the measurements. Of many different types of chemical sensors, fluorescence based sensing devices draw much attention as efficient yet small and straightforward devices, capable of detection of various analytes at extremely small quantities. Polymeric materials provide support for the fluorescent materials and usually serve as a host for the chromophores, protecting them from harsh environments, and serve as a transport media for the analyte. In the present study thin fluorescent polymer films, sensitive to the environment are synthesized and studied. Poly(glycidyl methacrylate) was used as a host material and Rhodamine B (RhB) was used as a fluorescent material. PGMA-RhB polymer films deposited on the flat surface of silicon wafers and glass slides showed the ability to uptake vapor of organic solvents from the vapor phase. It was observed, that during the swelling of the film fluorescent emission of the RhB molecules changes. Those changes were attributed to the variations in the RhB immediate environment, therefore confirming the sensitivity of the PGMA-RhB layer to the environmental changes. The fluorescent response of the PGMA-RhB layer was unique for each analyte used in the study and could be tuned by grafting of non-fluorescent layer to the surface of PGMA-RhB. Four different polymers (polystyrene, poly(2-vinyl pyridine), polyacrylic acid, and polyethylene glycol) were grafted to the surface of PGMA-RhB and each of the polymers grafted induced unique changes of fluorescent response of the PGMA-RhB. The attachment of the sensitive fluorescent layers to the surface of silica nanoparticles and fibers of Polyethylene terephthalate fabrics was performed. The sensitivity of the PGMA-RhB layers of structures with high roughness was improved, while the ability to tune the fluorescent response of the system was retained. Overall the studies have shown, that proposed method of fluorescent response tuning could be used in sensing applications