Layer buildup and structure from drying deposited droplets

• Applicant: Professor Dr.-Ing. Evangelos Tsotsas
• Subject Area: Chemical and Thermal Process Engineering ; Mechanical Process Engineering
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 398376893

Goal of this project is to experimentally replicate in a droplet-by-droplet manner how layers are successively built from drying droplets that contain solid material. Contour and porosity will be measured incrementally during layer buildup by means of white light interferometry. We will go to the smallest droplet size that can be produced and gently deposited by micropipette technology. The investigation will embrace very different fluids (salt solutions, nanosuspensions, microsuspensions) for drying conditions up to technical processing conditions. In this way new insights are expected about the evolution of the structure of porous layers produced by simultaneous spraying and drying, and indirectly also about many end-use properties that depend on coating structure. Mechanisms with an influence on structure formation and their interactions will be identified and analyzed, aiming at regime maps and first correlations of at least partial validity. Finally, experiments designed for same drying conditions will enable a comparison of the ex-situ layer formation measurements with coating in spray fluidized beds.

• DFG Programme: Research Grants