| Abstract
| - Thiol end-functionalized polystyrene chains have been introduced onto the surface of gold nanoparticles via atwo-step grafting-to method. This simple grafting procedure is demonstrated to be efficient for gold nanoparticles ofdifferent sizes and for particles initially dispersed in either aqueous or organic media. The method has been appliedsuccessfully for a relatively large range of polystyrene chain lengths. Grafting densities, as determined bythermogravimetric analysis, are found to decrease with increasing chain length. In all cases, the grafting densityindicates a dense brush conformation for the tethered chains. The resulting functionalized nanoparticles self-organizeinto hexagonally ordered monolayers when cast onto solid substrates from chloroform solution. Furthermore, thedistance between the gold cores in the dried monolayer is controlled by the molecular weight of the grafted polystyrene.Optical absorption spectra recorded for the organized monolayers show the characteristic plasmon absorption of thegold particles. Importantly, the plasmon resonance frequency exhibits a distinct dependence on interparticle separationthat can be attributed to plasmon coupling between neighboring gold cores.
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