(200e) Tailoring the Properties of Micro-Particles for Industrial Applications Using Dry Powder Coating

In industry there is a rising demand for fine powders, e.g. for powder coatings or pharmaceutical applications like enhanced dry powder inhalers. However, the processing of fine-grained particles with diameters between 1 and 10 microns is complicated due to strong van-der-Waals attraction forces. With increasing fineness of the particles, the van-der-Waals-force between the particles increases in comparison to the gravity force. This effect causes the particles to agglomerate or to stick to surfaces. In order to improve the handling properties, the fine-grained particles (host-particles) are coated with various nano-particles (guest-particles). This process is conducted in various liquids since the attraction forces between the particles are reduced and various effects can be used to tailor the properties of the coated host-particles. By the surface coating both the flow characteristics and other physical properties like solubility and adsorption parameters are changed. The modified properties depend on the coating process and the properties of the host- and guest-particles. By parameter variations the properties of the composite particles, i.e. the coated host-particles, can be systematically adjusted to the requirements of industrial applications. The changed particle-particle interactions can be tested using an atomic force microscope for measuring single-particle forces and both a laboratory bubbling fluidized or a shear cell to describe the bulk properties. These tests describe the silo storage behavior or the conveying behavior of the tailor-made composites, respectively. Changed physical properties can be characterized using both adsorptions and solubility tests. Both the appropriate particle processing and methods to characterize the tailor-made functionalized micro-particles are given.