Interfacial Assembly of 2D Superlattices and Quasicrystals in Binary Nanoparticle Systems with Strong Unlike Interactions
Year: 2026
Type: preprint
Abstract: Two-dimensional nanoparticle (NP) superlattices assembled at fluid–fluid interfaces offer a versatile platform for creating novel materials with applications in plasmonics, spectroscopy, photonics, and catalysis. Recently, we implemented a basin-hopping Monte Carlo approach to identify ground-state configurations of binary NP assemblies at fluid interfaces, which helped predict a range of ordered superlattices, several of which have been observed experimentally. Here, we extend this approach by allowing unlike-particle interactions to vary independently of like-particle interactions, an experimentally relevant feature not considered in our previous work that captures systems such as oppositely charged or chemically dissimilar NPs. We systematically map the resulting phase behavior as a function of particle size ratio, NP-fluid interaction asymmetry, and unlike-interaction strength. The resulting structural transitions reveal how preferred immersion depths, geometric packing, and particle coordination collectively govern assembly. Strengthening unlike-particle attraction shifts phase boundaries toward structures with greater unlike-particle coordination, suppresses phase-separated and like-contact-dominated regions, and stabilizes new crystalline phases inaccessible when unlike interactions are constrained by the like-particle interactions. At strong unlike attraction, additionally varying particle composition gives rise to periodic approximants and quasicrystalline structures with 12-fold and 8-fold symmetry. Collectively, these results establish how particle size asymmetry, differential interfacial affinity, and independently tunable like and unlike interactions can be used to direct structural selection in binary NP assemblies at fluid interfaces.
Source: ChemRxiv
Authors: Şafak Çallıoğlu, Gaurav Arya
Institution: Duke University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: G1186292489, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G3406661761, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5212984984, G5282220012, G6121277264, UC San Diego MRSEC: an NSF Materials Research Science and Engineering Center, G6965887028, G8174472116, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, G8412107296
OpenAlex ID: W7222289548