Defined core–shell particles as the key to complex interfacial self-assembly

Menath, Johannes; Eatson, Jack; Brilmayer, Robert; Andrieu-Brunsen, Annette; Buzza, D. Martin A.; Vogel, Nicolas

Abstract

The two-dimensional self-assembly of colloidal particles serves as a model system for fundamental studies of structure formation and as a powerful tool to fabricate functional materials and surfaces. However, the prevalence of hexagonal symmetries in such self-assembling systems limits its structural versatility. More than two decades ago, Jagla demonstrated that core–shell particles with two interaction length scales can form complex, nonhexagonal minimum energy configurations. Based on such Jagla potentials, a wide variety of phases including cluster lattices, chains, and quasicrystals have been theoretically discovered. Despite the elegance of this approach, its experimental realization has remained largely elusive. Here, we capitalize on the distinct interfacial morphology of soft particles to design two-dimensional assemblies with structural complexity. We find that core–shell particles consisting of a silica core surface functionalized with a noncrosslinked polymer shell efficiently spread at a liquid interface to form a two-dimensional polymer corona surrounding the core. We controllably grow such shells by iniferter-type controlled radical polymerization. Upon interfacial compression, the resulting core–shell particles arrange in well-defined dimer, trimer, and tetramer lattices before transitioning into complex chain and cluster phases. The experimental phase behavior is accurately reproduced by Monte Carlo simulations and minimum energy calculations, suggesting that the interfacial assembly interacts via a pairwise-additive Jagla-type potential. By comparing theory, simulation, and experiment, we narrow the Jagla g-parameter of the system to between 0.9 and 2. The possibility to control the interaction potential via the interfacial morphology provides a framework to realize structural features with unprecedented complexity from a simple, one-component system.

Citation

Menath, J., Eatson, J., Brilmayer, R., Andrieu-Brunsen, A., Buzza, D. M. A., & Vogel, N. (2021). Defined core–shell particles as the key to complex interfacial self-assembly. Proceedings of the National Academy of Sciences of the United States of America, 118(52), Article e2113394118. https://doi.org/10.1073/pnas.2113394118

• Journal Article Type: Article
• Acceptance Date: Nov 9, 2021
• Online Publication Date: Dec 23, 2021
• Publication Date: Dec 28, 2021
• Deposit Date: Jan 28, 2022
• Publicly Available Date: Jun 24, 2022
• Journal: Proceedings of the National Academy of Sciences
• Print ISSN: 0027-8424
• Publisher: National Academy of Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 118
• Issue: 52
• Article Number: e2113394118
• DOI: https://doi.org/10.1073/pnas.2113394118
• Keywords: Colloids; Microgels; Self-assembly; Interfaces; Interactions
• Public URL: https://hull-repository.worktribe.com/output/3905071