Particle & Particle Systems Characterization

Using image analysis as a reference method for particle sizing with measurement errors of less than 1 % is quite challenging. For this purpose a pixel array has been modeled to examine the influence, upon image analysis measurement accuracy, of pixel number, threshold levels and image centring.

The Laser-Diffraction Technique applied to sprays is sensitive to the drop shape. Comparison to image analysis and application of the recently developed surfacescale distribution is performed. This way a relationship between the mean-diameter series and the mean-scale series is established. This indicates that information on the droplet shape is available in the mean-diameter series reported by the laser diffraction.

Small angle neutron scattering (SANS) patterns were interpreted using model fitting and indirect Fourier transform methods. Furthermore, by modeling the effective structure factor particle interactions are determined. An indirect Fourier transform is found to be a more robust method to calculate the radial distribution function for interacting particles.

ZnO nanoparticle inception within mordenite and zeolites was achieved via ion exchange followed by NaOH leaching and thermal treatment. ZnO particles were characterized by high resolution electron microscopy; further characterization included X-ray diffraction, thermogravimetric analysis, and N₂ sorption as well as ICP-AE spectrometry and XPS. The final zeolite products are endowed with a twofold micromesoporosity.

A new nanoparticle reference material (RM) consisting of silica nanoparticles suspended in an aqueous solution is presented. Particle size distribution, homogeneity and stability are characterized thoroughly. The differences obtained by dynamic light scattering and centrifugation are discussed in detail.