The synthesis of Ag-polypyrrole nanocomposite coated latex particles and their application as a fluorescent quenching agent

Submicron-sized Ag-polypyrrole/poly(styrene-co-methacrylic acid) (Ag-PPy/P(St-co-MAA)) composite particles were fabricated via a redox reaction between pyrrole and AgNO3 in the presence of P(St-co-MAA) soap-free latex. The products are characterized by transmission electron microscopy (TEM), electron diffraction spectra (EDS), Raman spectra, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results showed that Ag-PPy nanocomposites were in situ deposited onto the surface of P(St-co-MAA) latex particles tailored by carboxylic-acid groups. The nanocomposites of Ag-PPy distributed on the surface of polymer particles transformed from discretely dots to continuously coating as the reaction temperature increased from 15A degrees C to 60A degrees C. Strawberry-like composite particles were obtained at the reaction temperature of 60A degrees C. The TGA characterization confirmed that the Ag-PPy nanocomposites loading onto the P(St-co-MAA) particles were systematically controlled over a range of 6 wt%-42 wt% by changing the reaction temperatures. The fluorescence quenching effect of the Ag-PPy/P(St-co-MAA) composite particles was explored on Rhodamine B as a model molecule with the Stern-Volmer quenching constant K (SV) of 5.9 x 10(4) (g/mL)(-1). It is suggested that the fluorescence quenching effect is caused by the resonance energy transfer mechanism.