EMRP - Nanoparticles: Traceable characterization of nanoparticles

• Forschungsstelle: METAS
• Projektnummer: 5115.08.FP.064
• Projekttitel Englisch: EMRP - Nano particles

Schlüsselwörter (Englisch)

Nanoparticles, Size calibration, Size distribution, Aerosols, high-aspect ratio

Kurzbeschreibung (Englisch)

Ever since the development of nanoparticles in the late 1960’s and early 1970’s they have been known to act as a bridge between atomic structures and bulk properties. This means they have potentially unique properties, for example as highly concentrated suspensions in the ink industry as drug delivery agents for the pharmaceutical industry, and in novel composite materials. Additional toxicological concerns require strict and well define standards to be applied. Currently no recognized traceable calibration of nanoparticles exists and new metrological capabilities are required in order to ensure consistency in quality and innovation. Whilst many different technologies exist to analysis nanoparticles they often give different, and sometimes conflicting, results and if not used correctly give misleading data.

In this project a consortium of National Metrology Institutes across Europe, NPL (UK), PTB (Germany), INM (Romania), INRIM (Italy), METAS (Switzerland) and CMI (Czech Republic) have combined to jointly tackle the size and shape measurement issues of nanoparticles highlighted above.

This project is partly funded by the European Community’s Seventh Framework Programme, ERA-NET Plus under Grant Agreement No 217257.

Projektziele (Englisch)

This project will develop the methods needed for traceable measurement of nanoparticles size distribution.

Abstract (Englisch)

Within the frame of this project, METAS developed procedures to calibrate the diameter of spherical nanoparticles by means of traceable atomic force microscopy (AFM). The performed studies covered fields such as sample preparation methods, measurement techniques, data evaluation and methods to estimate the uncertainty of measurement.
To improve the measurement uncertainty, estimation for AFM measurements on distorted hexagonal single particle layers, numerical simulations were made to investigate the effect of the width of the size distribution on the average lateral particle distance.
Finally, the goals of the project were verified through a measurement comparison which was carried out among the participating National Metrology Institutes. Seven high quality particle samples made from three different materials and having nominal sizes in the range from 10 nm to 200 nm served as transfer standards. The participants applied five fundamentally different measurement methods such as atomic force microscopy (AFM), dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and scanning electron microscopy in transmission mode (TSEM) and provided a total of 48 independent and in house traceable results. The comparison reference values had combined standard uncertainties smaller than 1 nm for particles with sizes up to 100 nm. As the pilot laboratory in this comparison METAS acquired and distributed the samples, evaluated the results and prepared the final comparison reports. Practical instructions for particle size measurements using various methods were summarised in a publicly available Good Practice Guide.

Umsetzung und Anwendungen (Englisch)

The developed and validated procedures for the diameter calibration of spherical nanoparticles are now be offered as a calibration services. The set of particles used in the comparison serves in future as a low uncertainty reference. The Good Practice Guide will help to improve the METAS calibration instructions for particle size measurements by SPM methods.

Publikationen / Ergebnisse (Englisch)

Felix Meli, Tobias Klein, Gudrun Gleber,Michael Krumrey, Alexandru Duta, Steluta Duta, Virpi Korpelainen, Roberto Bellotti, Gian Bartolo Picotto, Robert D. Boyd, Alexandre Cuenat, “Traceable size determination of nanoparticles, a comparison among European metrology institutes”, Journal of Measurement Science and Technology, to be published.

Robert D. Boyd, Alexandre Cuenat, Felix Meli, Carl Georg Frase, Tobias Klein, Michael Krumrey, Gudrun Gleber, Alexandru Duta, Steluta Duta, Richard Hogstrom and Emilio Prieto, “Good Practice Guide for the determination of the size distribution of spherical nanoparticle samples”, EMRP Good Practice Guides.