Neue Verfahren zur Bestimmung von Nanopartikeln in Feststoffen
Materialwissenschafter an der NPL entwickeln optische Verfahren, um die Menge und Verteilung von Nanopartikeln in Materialien zu messen. Bereits sehr geringe Konzentrationen an Nanopartikeln können auf die Eigenschaften eines Materials grosse Auswirkungen haben. Kohlenstoff-Nanoröhrchen beispielsweise können bereits bei 0.5wt% (Gewichtsprozente) die elektrische Leitfähigkeit eines Materials um einen Faktor von bis zu einer Million erhöhen. Doch dafür müssen die Nanopartikel gleichmässig im Material verteilt sein, was wiederum die genaue Bestimmung von Partikelmenge und Verteilung im Material notwendig macht.
NPL is developing three optical techniques that use light scattering to make these measurements in solid polymers: frequency-domain optical coherence tomography (FD-OCT), Fraunhofer wavefront correlation (FWC) and oscillatory photon correlation spectroscopy (Os-PCS). NPL's Bill Broughton and Triantafillos Koukoulas authored an article that appeared in the May 2011 edition of Materials World describing this work.
These new techniques could help industry develop and monitor products that use nanoparticle-containing materials, known as nanocomposites. Although each technique is different, they all use the variation in refractive index between nanoparticles and the polymer material they are embedded in, which leads to a difference in the scattering of light. The ability to detect this light-scattering means that the content and distribution of nanoparticles can be measured. The aim is also to expand these methods to use infrared light so that they can analyse samples of varying transparencies.
The development of these techniques will better enable industry to realise the potential of nanocomposites by providing a versatile and reliable way to measure the different types of nanoparticles that give them their extraordinary properties.
For more information, please contact Bill Broughton.
Quelle: National Physical Laboratory (NPL)
Bild: NPL's dual-beam photon correlation spectroscopy system