European Commission, DG Joint Research Centre, Ispra, Italy, Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland, Univ. Grenoble Alpes, Grenoble, France, CEA, LETI, Minatec Campus, Grenoble, France, CEA, LITEN, Minatec Campus, Grenoble, France

Our article dissects the problem of understanding the origin of size heterogeneity in polydispersed nanoparticle samples. A commercially available multimodal material representing a typical borderline case of the nano definition is characterised with various state of the art techniques. We focus on dimer (multimer) recognition capability of different techniques, considering the potential of single and combined analytical solutions. The performance of dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), online coupled asymmetric field flow fractionation-multi angle light scattering (MALS)-DLS (FFF-MALS-DLS), tunable resistive pulse sensing (TRPS), centrifugal liquid sedimentation (CLS), analytical ultracentrifugation (AUC) and transmission electron microscopy (TEM) is discussed. NTA, TRPS and FFF-MALS are shown to resolve the multimodal size distribution of the sample, while batch mode DLS, the most widespread tool in characterisation laboratories, fails. Besides of complex methods like TEM imaging after FFF separation and FFF-MALS-DLS in combination with adequate mathematical shape factor models, centrifugal methods are documented as simple analytical tools that are able to indicate the presence of dimers made of rigid spherical nanoparticles. © 2017 The Royal Society of Chemistry.

Centrifugation, High resolution transmission electron microscopy, Light scattering, Nanoparticles, Transmission electron microscopy, Analytical ultracentrifugation, Asymmetric field flow fractionations, Multi-angle light scatterings, Nanoparticle Characterisation, Nanoparticle tracking analysis, Resistive pulse sensing, Spherical nanoparticles, State-of-the-art techniques, Dynamic light scattering