A Review on Self‐Assembly of Colloidal Nanoparticles into Clusters, Patterns, and Films: Emerging Synthesis Techniques and Applications

Abstract

The colloidal synthesis of functional nanoparticles has gained tremendous scientific attention in the last decades. In parallel to these advancements, another rapidly growing area is the self‐assembly or self‐organization of these colloidal nanoparticles. First, the organization of nanoparticles into ordered structures is important for obtaining functional interfaces that extend or even amplify the intrinsic properties of the constituting nanoparticles at a larger scale. The synthesis of large‐scale interfaces using complex or intricately designed nanostructures as building blocks, requires highly controllable self‐assembly techniques down to the nanoscale. In certain cases, for example, when dealing with plasmonic nanoparticles, the assembly of the nanoparticles further enhances their properties by coupling phenomena. In other cases, the process of self‐assembly itself is useful in the final application such as in sensing and drug delivery, amongst others. In view of the growing importance of this field, this review provides a comprehensive overview of the recent developments in the field of nanoparticle self‐assembly and their applications. For clarity, the self‐assembled nanostructures are classified into two broad categories: finite clusters/patterns, and infinite films. Different state‐of‐the‐art techniques to obtain these nanostructures are discussed in detail, before discussing the applications where the self‐assembly significantly enhances the performance of the process.

Nanofiber Scaffolds as Drug Delivery Systems Promoting Wound Healing

“…After self-assembly of the nanofibrous structures, they can be fixed onto a scaffold using solidification methods (e.g., solvent evaporation, cross-linking, and chemical reduction) [ 46 ]. The solvent and unreacted materials are removed by washing, resulting in a dry nanofiber scaffold [ 47 ]. As shown in Figure 1 c, Yosuke Hisamatsu et al reported a self-assembled amphiphilic 4-aminoquinoline (4-AQ)-tetraphenylethylene (TPE) conjugate using a self-assembly process involving the formation of spherical nanoparticles, transition to short nanofibers, and growth to long nanofibers at room temperature.…”

2D superlattices via interfacial self-assembly of polymer-grafted Au nanoparticles

“…142,143 The above applications were summarized in previous review articles. 101,102,144 Herein, we focus on recent progress in NFGM devices based on 2D superlattices of polymer-grafted Au NPs.…”

“…The liquid interface provides an ideal substrate for the diffusion and self-assembly of NPs because the fluidity of the liquid can avoid surface defects. 88,[97][98][99][100][101][102][103][104] The essence of NP assembly is an adsorption process in which NPs are trapped on the phase interface. During the process, the NPs require an extra driving force to overcome high adsorption barriers and then be attracted to low-tension interfaces.…”

“…142,143 The above applications were summarized in previous review articles. 101,102,144 Herein, we focus on recent progress in NFGM devices based on 2D superlattices of polymer-grafted Au NPs. SAXS curves of the 2D NP superlattices prepared without solvent vapour; the structural evolution of (f) AuNP 15nm @PS 12k and (g) AuNP 15nm @PS 22k measured by in situ GISAXS under a steam atmosphere.…”

Effect of Particle–Substrate Interactions on Colloidal Layer Structure Prepared by Convective Self-Assembly Using Polyelectrolyte-Grafted Silica Particles

“…The colloidal layers have attracted widespread attention from researchers and engineers and been extensively investigated so far − because of their potential applications such as optical devices, − sensors, , and data storage . Most of the colloidal layers in the reported studies have a close-packed (CP) structure, and their properties depend not only on the particle types but also on the distance between particle centers.…”