| AVS 64th International Symposium & Exhibition | |
| Applied Surface Science Division | Monday Sessions |
| Session AS+BI+MI-MoM |
| Session: | Practical Surface Analysis: Getting the Most Out of Your Analysis using Complementary Techniques |
| Presenter: | David Cant, National Physical Laboratory, UK |
| Authors: | D.J.H. Cant, National Physical Laboratory, UK C. Minelli, National Physical Laboratory, UK K. Sparnacci, Università degli Studi del Piemonte Orientale, Italy W. Unger, Bundesanstalt für Materialforschung und -prüfung (BAM), Germany A. Hermanns, Bundesanstalt für Materialforschung und -prüfung (BAM) W.S.M. Werner, TU Wien, Austria H. Kalbe, TU Wien, Austria R. Garcia-Diez, Physikalisch-Technische Bundesanstalt, Germany C. Gollwitzer, Physikalisch-Technische Bundesanstalt, Germany M. Krumrey, Physikalisch-Technische Bundesanstalt, Germany A.G. Shard, National Physical Laboratory, UK |
| Correspondent: | Click to Email |
Core-shell nanoparticles are commonly used in a variety of applications, including medicine, catalysis, optoelectronics, and others. Accurate identification of core-shell nanoparticle structure and morphology is an important challenge to overcome before such nanoparticles can be effectively utilised. This is not necessarily a trivial obstacle, as no single characterisation technique can accurately identify every possible peculiarity of structure or composition that may exist.
For example, characterisation methods that observe bulk properties, such as differential centrifugal sedimentation (DCS), thermogravimetric analysis (TGA), or techniques based on observation of Brownian motion such as dynamic light scattering (DLS) may be unable to distinguish particles with a standard core-shell morphology from those with the same core and shell masses, but with an uneven shell, or where the core and shell have merged to form a homogenous particle.
Similarly, surface sensitive techniques which analyse a population of particles, such as x-ray photoelectron spectroscopy (XPS) or small angle x-ray scattering (SAXS), may be able to provide information on shell thicknesses in standard core-shell particles and distinguish them from particles with an uneven shell or a homogenous particle, but may have difficulty distinguishing homogeneity from an uneven shell or off-centred core.
Techniques that allow observation of individual particles, such as electron microscopy, may be able to clearly show the structure, but are rarely able to provide any in-depth quantification of the composition. As such it is necessary to use a careful selection of appropriate techniques to fully characterise any given nanoparticle system. To illustrate these issues, two polymeric core-shell nanoparticle systems have been characterised, both consisting of a Hyflon® core coated in varying thicknesses of either PMMA or polystyrene. These systems are nominally very similar, but differ notably in structure. The results from several different characterisation techniques (XPS, SAXS, DCS, TGA, DLS, and SEM.) were compared in order to demonstrate the difference in information provided by each and obtain a full understanding of both types of nanoparticle.