Nanoseminar 28 October - Marjolein de Jager MSc

Speaker: Marjolein de Jager 

Title: To be hard, or not to be hard: Crystal nucleation of highly screened charged colloids

Abstract: Hard spheres are, arguably, the archetypical model system for studying colloidal self-assembly and have been instrumental in our understanding of many important phenomena, such as e.g. phase transitions, glassy behavior, and defects. Experimentally, hard spheres are typically realized as colloidal particles suspended in a solvent. However, in such systems the colloids nearly always carry surface charges. This raises an important fundamental question: when can these experimental “hard” colloids be seen as actual hard spheres? In order to answer this question, we studied the equilibrium phase behavior and crystal nucleation (rate) of highly screened charged colloids to identify the effect of charge. In the first part of this talk I will present our findings [1], and in particular show that the effective phase behavior and nucleation rate are extremely sensitive to the presence of even very small amounts of surface charge. Next, in the second part of this talk, I will focus more on the onset of crystal nucleation by exploring the possible existence of hidden local motifs, i.e. a precursor, in the metastable fluid that could predate the birth of a crystal nucleus.

[1] M. de Jager & L. Filion, J. Chem. Phys. 157, 154905 (2022); https://doi.org/10.1063/5.0117867