title: Determination of nanoparticle size distribution together with density or molecular weight by 2D analytical ultracentrifugation.
abstract: Nanoparticles are finding many research and industrial applications, yet their characterization remains a challenge. Their cores are often polydisperse and coated by a stabilizing shell that varies in size and composition. No single technique can characterize both the size distribution and the nature of the shell. Advances in analytical ultracentrifugation allow for the extraction of the sedimentation (s) and diffusion coefficients (D). Here we report an approach to transform the s and D distributions of nanoparticles in solution into precise molecular weight (M), density (ρ(P)) and particle diameter (d(p)) distributions. M for mixtures of discrete nanocrystals is found within 4% of the known quantities. The accuracy and the density information we achieve on nanoparticles are unparalleled. A single experimental run is sufficient for full nanoparticle characterization, without the need for standards or other auxiliary measurements. We believe that our method is of general applicability and we discuss its limitations.
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Randy P
authors.initials: RP
authors.lastname: Carney
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Huifeng
authors.initials: H
authors.lastname: Qian
authors.forename: Rongchao
authors.initials: R
authors.lastname: Jin
authors.forename: Hakim
authors.initials: H
authors.lastname: Mehenni
authors.forename: Francesco
authors.initials: F
authors.lastname: Stellacci
authors.forename: Osman M
authors.initials: OM
authors.lastname: Bakr
mesh_terms: D019540:Area Under Curve; D006046:Gold / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D008970:Molecular Weight; D053758:Nanoparticles / Q000032:analysis*; D010316:Particle Size; D013816:Thermodynamics; D014461:Ultracentrifugation / Q000379:methods*
chemical_list: D006046:Gold