Order and disorder in powder mixtures: Spatial distribution functions as tools to assess powder homogeneity
2009 (English)In: Particle & particle systems characterization, ISSN 0934-0866, E-ISSN 1521-4117, Vol. 25, no 5-6, 397-405 p.Article in journal (Refereed) Published
In interactive mixtures with small carrier particles, the content variability is often higher than predicted by available models despite the significant degree of interaction visualized with Scanning Electron Microscopy (SEM). The present work details how pair-correlation functions can be used to reveal information about the spatial distribution of mixture constituents and their interactions. SEM pictures of a 2 % w/w oxazepam/sodium starch glycolate (SSG) mixture were recorded (n = 14). The constituent coordinates were extracted and pair-correlation functions as well as the cross-correlation function were calculated. A significant degree of interaction was observed between the constituents in the experimental mixture, compared to a randomized control system. In particular, the probability of finding an oxazepam particle was especially high inside the perimeter of the carrier particle and along its edges. The observed cross-correlation between oxazepam and SSG particles was periodic and repeated at distances corresponding to 1-1.5 carrier diameters. It was concluded that interactive mixtures of powders can be compared to disordered/amorphous solids since both exhibit short-range order, whilst lacking long-range translational periodicity.
Place, publisher, year, edition, pages
2009. Vol. 25, no 5-6, 397-405 p.
dry coating, homogeneity, interactive mixtures, pair-correlation functions
Engineering and Technology
Research subject Engineering Science with specialization in Nanotechnology and Functional Materials
IdentifiersURN: urn:nbn:se:uu:diva-99435DOI: 10.1002/ppsc.200701129ISI: 000264830700001OAI: oai:DiVA.org:uu-99435DiVA: diva2:207909