title: How a Nanostructure's Shape Affects its Lifetime in the Environment: Comparing a Silver Nanocube to a Nanoparticle When Dispersed in Aqueous Media.
abstract: Herein, we detail how the morphology of a nanomaterial affects its environmental lifetime in aquatic ecosystems. In particular, we focus on the cube and particle nanostructures of Ag and age them in various aquatic mediums including synthetic hard water, pond water, and seawater. Our results show that in the synthetic hard water and pond water cases, there was little difference in the rate of morphological changes as determined by UV-vis spectroscopy. However, when these samples were analyzed with transmission electron microscopy, radically different mechanisms in the loss of their original nanostructures were observed. Specifically, for the nanocube we observed that the corners of the cubes had become more rounded, whereas the aged nanoparticles formed large aggregates. Most interestingly, when the seawater samples were analyzed, the nanocubes showed a substantially higher stability in maintaining the nano length scale in comparison to nanoparticles overtime. Moreover, high-resolution transmission electron microscopy analysis allowed us to determine that Ag+ ions diffused away from both the edge and from the faces of the cube, whereas the nanoparticle rapidly aggregated under the harsh seawater conditions.
authors.affiliation: Georgia Electron Microscopy, University of Georgia , Athens, Georgia 30622, United States.
authors.forename: Eric V
authors.initials: EV
authors.lastname: Formo
authors.affiliation: Georgia Electron Microscopy, University of Georgia , Athens, Georgia 30622, United States.
authors.forename: Caroline B
authors.initials: CB
authors.lastname: Potterf
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Miaoxin
authors.initials: M
authors.lastname: Yang
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Unocic
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Donovan N
authors.initials: DN
authors.lastname: Leonard
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
authors.forename: Michelle
authors.initials: M
authors.lastname: Pawel
mesh_terms: D053768:Metal Nanoparticles / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D049329:Nanostructures / Q000737:chemistry; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D012834:Silver