Conjugated polymer to gold nanoparticles passivation. Synthesis, characterization and photophysics interpretation.

The association of gold nanoparticles with polymer chains in optical sensors provides a means of enhancing the differences of refraction index which are probed by the device, increasing its reaching and selectivity (Scientific American, 2007, v. 296, n. 4, p. 56-63). Here the synthesis of a thiol containing polyfluorene derivative [poly(9,9´-diyl)bis(hexane-1-thiol-fluorene-alt-2,7-dihexyfluorene)] (LaPPS79) are described, along with the corresponding system in which the polymer acts as a passivating agent for gold nanoparticles, shown in scheme 1. The properties of the pristine polymer and those of the system polymer/gold nanoparticles when compared showed an increase in the intensity and a redshift of the plasmon band of the nanoparticles. The formation of an ordered system was also observed by transmission electron microscopy.