Core−Shell Poly(allyamine hydrochloride)-Pyrene Nanorods Decorated with Gold Nanoparticles

Water-dispersible and fluorescent core−shell nanorods (NRs) consisting of covalently linked poly(allyamine hydrochloride)-pyrene (PAH-Py) were synthesized and used for fabricating hybrid organic−inorganic NRs. The reaction between 1-pyrenecarboxaldehyde (Py-CHO) nanorods and PAH was driven by Schiff base formation and followed by NaBH4 reduction, and caused 28% mass loss of Py molecules at the final stage (2 h). The final PAH-Py NRs contained 42% PAH, corresponding to a Py substitution ratio of 34.5%. They were uniform in size with a PyCHO core (81.2 ± 16.4 nm) and PAH shell (45.0 ± 8.8 nm) fibrillar structure, and had a surface zeta potential of 53.7 ± 5.1 mV. The PAH-Py NRs could survive after annealed at 80 °C or dispersed in ethanol, and showed good suspension stability in water. Because of the functional amino groups, the nanorods could act as nanoanchors to immobilize either positively or negatively charged gold nanoparticles, or as nanoreactors to synthesize gold and platinum nanoparticles in situ. Very small quenching of the fluorescence was achieved due to the isolation effect of the PAH layer. The method described here provides a new approach for modifying organic surfaces with nanoparticles and endowing them with multiple functions.