Particle dispersion and deposition in evaporating sessile droplets

• Applicant: Professor Dr. Berend van Wachem, Ph.D.
• Subject Area: Mechanical Process Engineering ; Fluid Mechanics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452916560

Sessile particle-laden droplets deposit the particles suspended in them on the substrate as they evaporate, yielding a broad variety of particle deposition patterns. The control of the shape and characteristics of these particle deposits can be of critical importance for many applications, ranging from inkjet printing to RNA sequencing. However, despite substantial research efforts dedicated to particle deposition by evaporating sessile droplets, we still lack a basic understanding of many aspects of the particle dispersion and deposition process. In particular a detailed quantification of the individual contributions of particle-particle and particle-substrate interactions, particle assembly at the gas-liquid interface, and particle size distributions is not available to date. With this in mind, the primary objectives of this project are: (i) quantifying the influence of attractive van-der-Waals forces on the particle dispersion, (ii) identifying optimal conditions for particle assembly at the gas-liquid interface, and (iii) analyzing the influence of the particle size distribution of polydispersed particle populations in regard to the dispersion and separation of particles by size, for spherical and ellipsoidal particles. To enable this research, we will develop an efficient simulation tool to simulate the evaporation of particle-laden sessile droplets, resolving all relevant physical mechanisms, and including capillary attraction of particles at the gas-liquid interface.

• DFG Programme: Research Grants
• International Connection: Turkey
• Co-Investigator: Professor Dr. Fabian Denner
• Cooperation Partners: Professor Dr. Luca Biancofiore, Ph.D.; Professorin Dr. Yegan Erdem, Ph.D.