Kinetically Controlled Site-Specific Self-assembly of Hairy Colloids

• Published in: Langmuir 2024-02, Vol.40 (5), p.2487-2499
• Main Authors: Vazirieh Lenjani, Shayan, Li, Cheng-Wu, Seçkin, Sezer, König, Tobias A. F., Merlitz, Holger, Sommer, Jens-Uwe, Rossner, Christian
• Format: Article
• Language: English
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.3c02207

The solvophobicity-driven directional self-assembly of polymer-coated gold nanorods is a well-established phenomenon. Yet, the kinetics of this process, the origin of site-selectivity in the self-assembly, and the interplay of (attractive) solvophobic brush interactions and (repulsive) electrostatic forces are not fully understood. Herein, we use a combination of time-resolved (vis/NIR) extinction spectroscopy and finite-difference time-domain (FDTD) simulations to determine conversion profiles for the assembly of gold nanorods with polystyrene shells of distinct thicknesses into their (tip-to-tip) self-assembled structures. In particular, we demonstrate that the assembly process is highly protracted compared with diffusion-controlled rates, and we find that the assembly rate varies for different thickness values of the polymer shell. Our findings were rationalized using coarse-grained molecular dynamics simulations, which also corroborated the tip-to-tip preference in the self-assembly process, albeit with a uniform polymer coating. Utilizing the knowledge of quantified conversion rates for distinct colloidal species, we designed coassembling systems with different brush thicknesses, featuring “narcissistic” self-sorting behavior. This provides new perspectives for high-level supracolloidal self-assembly.