Shape-Mediated Oriented Assembly of Concave Nanoparticles under Cylindrical Confinement

Abstract

This contribution describes the self-assembly of colloidal nanodumbbells (NDs) with tunable shapes within cylindrical channels. We present that the intrinsic concave geometry of NDs endows them with peculiar packing and interlocking behaviors, which, in conjunction with the adjustable confinement constraint, leads to a variety of superstructures such as tilted-ladder chains and crossed-chain superlattices. A mechanistic investigation, corroborated by geometric calculations, reveals that the phase behavior of NDs under strong confinement can be rationalized by the entropy-driven maximization of the packing efficiency. Based on the experimental results, an empirical phase diagram is generated, which could provide general guidance in the design of intended superstructures from NDs. This study provides essential insight into how the interplay between the particle shape and confinement conditions can be exploited to direct the orientationally ordered assembly of concave nanoparticles into unusual superlattices.

Controllable synthesis of star-shaped FeCoMnOx nanocrystals and their self-assembly into superlattices with low-packing densities

“…16 Despite these significant advances, previous research has predominantly focused on the assembly of convex NCs, with limited exploration in utilizing concave NC building blocks for constructing superlattice materials. [17][18][19] There have been some encouraging advances in the selfassembly of micron-sized colloids with concave features. For instance, Liu and colleagues demonstrated the formation of a unique 2D open superstructure using biconcave polystyrene discs.…”

“…16 Despite these significant advances, previous research has predominantly focused on the assembly of convex NCs, with limited exploration in utilizing concave NC building blocks for constructing superlattice materials. 17–19…”

Molecular Dynamics Simulation Study on Self-Assembly of Polymer-Grafted Nanocrystals: From Isotropic Cores to Anisotropic Cores

“…Benefiting from the advances in fabricating shape-anisotropic nanoparticles with high monodispersity and controllable particle size, , great progress has been made in the field of the assembly of shape-anisotropic nanocrystals. − Compared to spherical nanocrystals, shape-anisotropic nanocrystals can form more complex superstructures, especially the structures with long-range positional and orientational order, which have distinctive photoelectric, optical, and catalytic properties. − The geometrical shape of building blocks provides an important driving force named directional entropy for assembly . Directional entropy is the packing entropy of the particle shape; i.e., the packing entropy can be enhanced if anisotropic particles preferably orient.…”

Nanoarhitectonics of Inorganic–Organic Silica–Benzil Composites: Synthesis, Nanocrystal Morphology and Micro-Raman Analysis

“…The design of new functional materials consisting of two or more nanosized components has recently attracted great interest, as it opens up wide opportunities for creating materials with unique properties [ 1 , 2 ]. Special attention has been paid to nanoporous materials, which play the role of a host substance that can be filled with various guest compounds.…”