CTAB mediated reshaping of metallodielectric nanoparticles

We report on the dramatic chemical reshaping of metallodielectric nanoparticles upon exposure to cetyltrimethylammonium bromide (CTAB) in aqueous solutions. Metal nanoshells possessing a silica core with a gold shell were observed to undergo a morphological change from their initial shell structure to that of large, elongated gold nanoparticles or toroids. This reaction is dependent on the chemical species available in solution and on the metal shell thickness on the nanostructure. Surprisingly, dissolution of the silica core due to the presence of CTAB was also observed during the reshaping of the nanoshells.