Open-Access-Publication of the Month

18 July 2025

To encourage people to think outside the box, once a month the Central Library selects an open access publication from the JuSER publication database for the Forschungszentrum Jülich newsletter.

In the open access publication of the month for July 2025, Dr. Qingguang Xie, Dr. Tian Du, Prof. Christoph Brabec, and Prof. Jens Harting from HI ERN write about how tiny colloidal particles, suspended in liquid, can naturally arrange themselves into organized monolayers when the liquid dries.

Assembled monolayers of colloidal particles are crucial for various applications, including optoelectronics, surface engineering, light harvesting, and catalysis. A common approach for self-assembly is the drying of a colloidal suspension film on a solid substrate using technologies such as printing and coating. However, this approach often presents challenges such as low surface coverage and the formation of multiple layers.

Through simulations, the authors discover that higher substrate wettability results in a monolayer with a hexagonal arrangement of deposited particles on the substrate. Conversely, lower substrate wettability leads to droplet formation after the film ruptures, resulting in the formation of particle clusters. Furthermore, the authors reveal that higher particle wettability can mitigate the impact of substrate wettability and facilitate the formation of highly ordered monolayers. They develop theoretical models to predict the surface coverage fraction as a function of particle volume fraction, initial film thickness, particle radius, and both substrate and particle wettability. These models are validated by simulations.

Their findings provide valuable insights for optimizing the deposition process in the creation of assembled monolayers of colloidal particles.

Originalpublication

Effect of Particle and Substrate Wettability on Evaporation-Driven Assembly of Colloidal Monolayers
Langmuir 2025, 41, 23, 14995–15003
https://doi.org/10.1021/acs.langmuir.5c01195

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