Self-organization of colloidal particles during drying of a droplet: Modeling and experimental study

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Japan, 2018-12, Vol.29 (12), p.3542-3551
• Main Authors: Jabłczyńska, Katarzyna, Gac, Jakub M., Sosnowski, Tomasz R.
• Format: Article
• Language: English
• Subjects: Particle structure; Particle technology; Self-assembly; Spray drying
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2018.09.036

[Display omitted] •Aggregates show self-assembling due to the ordering of the internal structure.•A characteristic time-scale of equilibration inside a drying droplet exists.•A decrease of drying time results in more disordered aggregates.•Particle diffusion in the droplet determines the final structure of the aggregate. Formation of structurized micro/nanoparticle aggregates in spray drying process is analyzed theoretically and experimentally. Colloids of mono- and bimodal particle size distribution are used as the precursors to demonstrate different patterns of particle self-organization inside the drying droplet. In case of monodisperse primary particles their self-organization in the final aggregate results in either a hollow or a full (packed) spherical structure. For primary particles with bimodal size distribution, either the layered structure of aggregates is formed (with smaller particles forming outer layer and the bigger particles captured inside) or the ordering of bigger particles on the aggregate surface is observed, depending on process parameters. Numerical investigations allow to predict and explain the conditions at which self-assembling of particles within powder aggregates takes place.