Magnetism in Polymers with Embedded Gold Nanoparticles

Abstract

preserve the surprising magnetic properties induced at thenanoscale. NPs exhibit a large fraction of surface atoms, whichare different to those of the bulk volume mainly because ofthe broken symmetry at the surface, which alters their elec-tronic configuration and consequently their physical andchemical properties, depending on the electronic state. Al-though bulk materials also have surface atoms, they representa negligible fraction of the total, so their contribution to thephysical properties of the material is insignificant. Moreover,in the case of NPs, as the fraction of surface atoms stronglydepends on the particle size, so do their properties. Anotherinteresting feature of the surface atoms is that their propertiescan be modified by capping the NP with different chemicalspecies, which create bonds that induce a modification of thecharge distribution at the NP surface. A surprising example ofthese surface effects is the observation of magnetism in goldNPs capped with dodecanethiol, in spite of the diamagneticbehavior of the bulk gold, as noted above.