Study of the aggregation behavior of Janus particles by coupling experiments and Brownian dynamics simulations

Abstract

Hypothesis: New colloids such as inverse patchy particles or Janus particles are considered as smart building blocks in the development of innovative and performant materials. For example, the control of the self-assembly of oxide-based charged Janus particles is interesting for ceramic shaping. Thus, the synthesis of silica based Janus particles as well as a detailed study of their behavior in suspension are presented in this paper.

Experiments: Fluorescent silica particles are partially modified in surface by grafting amine groups using a Pickering emulsion route. Zeta potential measurements, sedimentation tests and confocal microscopy observations are carried out to analyze the aggregation of the obtained particles in aqueous suspension as a function of the patch size and of the pH. Brownian dynamics simulations are also performed to better understand the aggregate structures.

Findings: The aggregation of the synthesized silica-based Janus particles can be tuned by modifying the experimental parameters, and elongated or on the contrary more compact structures could be observed. This control of aggregation makes such particles promising to build new ceramic materials.

Keywords: Aggregation; Brownian dynamics simulations; Colloid; Confocal microscopy; Inverse patchy particles.