Tunable fluorescent poly(styrene-co-methacrylic acid)/Au-Aphen hybrid nanoparticles via surface immobilization

Tunable fluorescent poly(styrene-co-methacrylic acid) [poly(St-co-MAA)]/Au- Aphen hybrid nanoparticles were fabricated by immobilizing the 5-amino-1,10-phenanthroline functionalized gold nanoparticles (Au-Aphen) on the surface of copolymer nanoparticles in aqueous solution. Aphen-Au cationic complex was absorbed on the surface of poly(St-co-MAA) nanoparticles by using electrostatic interactions and metalized by a reduction process. Thus, the functionalized metal nanoparticles can be immobilized onto the surface of the copolymer nanoparticles to significantly modify their optical properties. The structure of the hybrid nanoparticles was confirmed by infrared spectroscopy, scanning electron microscopy, X-ray diffraction, UV-vis spectrophotometery and spectrofluorophotometery studies. These hybrid nanoparticles exhibited fluorescence properties with enhanced photoluminescence quantum yield compared to the gold clusters. Furthermore, the fluorescent emission wavelength of hybrid nanoparticles can be tuned precisely by changing the amount of Aphen functionalized gold nanoparticles on the surface of poly(St-co-MAA) nanoparticles. PL spectra of hybrid nanoparticles showed a red-shift with increasing the amount of functionalized gold on the poly(St-co-MAA) nanoparticles surface in a water medium.