Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)
O 35.127: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster B
Development of a System measuring Adhesion Forces in Powder Collectives — •Stefanie Wanka1, Michael Kappl1, Markus Wolkenhauer2, and Hans-Jürgen Butt1 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim, Germany
Fine powders commonly have poor flow ability and dispersibility due to interparticle adhesion that leads to formation of agglomerates. Knowing about adhesion in particle collectives is indispensable to gain a deeper fundamental understanding of particle behavior in powders. Especially in pharmaceutical industry a control of adhesion forces in powders is mandatory to improve the performance of inhalation products. Typically the size of inhalable particles is in the range of 1-5 μm. To measure adhesion forces in fine powder collectives a new method was developed which is based on particle detachment from a surface caused by its inertia. To achieve detachment of particles in the relevant size range, accelerations in the order of 500 000g are necessary. Existing techniques for measurement of particle adhesion forces are experimentally demanding and time consuming. Therefore we aim to develop a system that will allow routine measurements of adhesion in particle collectives. The acceleration required for particle detachment is provided by a shock excitation system based on the Hopkinson bar principle (SPEKTRA GmbH Dresden) and measured via laser vibrometry. Particle detachment events are detected by optical video microscopy. First test measurements showed successful detachment of particles < 10 μm and thus a proof of concept.