Functionalization of aerogel particles by coating in a spouted bed
Aerogels are porous and light-weighting materials with high specific surface area. Due to their properties they have been investigated as carriers of active ingredients. However, open pore structure limits their application because of changing their structure when they are exposed to liquids. Therefore, there is a protective layer on the surface of the aerogels needed, which preserves loaded drug or enables storage in liquid containing media. Furthermore, the knowledge of thickness of the applied coating layer is essential in order to predict the storage or release behavior. In this work a novel technique for measurement of coating layer thickness of fine particles is presented. This method is based on cross-sectioning of single coated particles in micrometer size range with focused ion beam (FIB). This technique has been tested on two batches of produced aerogel particles coated with thin coating layers in a spouted bed.