Programmed Self-Assembly of Branched Nanocrystals with an Amphiphilic Surface Pattern

Abstract

Site-selective surface modification on the shape-controlled nanocrystals is a key approach in the programmed self-assembly of inorganic colloidal materials. This study demonstrates a simple methodology to gain self-assemblies of semiconductor nanocrystals with branched shapes through tip-to-tip attachment. Short-chained water-soluble cationic thiols are employed as a surface ligand for CdSe tetrapods and CdSe/CdS core/shell octapods. Because of the less affinity of arm-tip to the surface ligands compared to the arm-side wall, the tip-surface becomes uncapped to give a hydrophobic nature, affording an amphiphilic surface pattern. The amphiphilic tetrapods aggregated into porous agglomerates through tip-to-tip connection in water, while they afforded a hexagonally arranged Kagome-like two-dimensional (2D) assembly by the simple casting of aqueous dispersion with the aid of a convective self-assembly mechanism. A 2D net-like assembly was similarly obtained from amphiphilic octapods. A dissipative particle dynamics simulation using a planar tripod model with an amphiphilic surface pattern reproduced the formation of the Kagome-like assembly in a 2D confined space, demonstrating that the lateral diffusion of nanoparticles and the firm contacts between the hydrophobic tips play crucial roles in the self-assembly.

Tunable Assembly of Organic–Inorganic Molecules into Hierarchical Superstructures as Ligase Mimics for Enhancing Tumor Photothermal Therapy

“…[20] Furthermore, the structural complexity and poor tunability of nanoscale units are restricted by the limited geometries of the anisotropic nanoparticles. [21] Organizing organic-inorganic molecules into tunable superstructures which comprise multiple structures or morphologies remains greatly challenging. [22][23][24][25] Dopamine, as a kind of polyphenols, contains a large amount of catechol and has a strong chelating ability to a variety of metal ions.…”

Shape-directed self-assembly of nanodumbbells into superstructure polymorphs

“…Furthermore, the geometry features of NPs play a key role in determining their assembly behaviors, and a diverse and complex assortment of analogous superstructures such as crystals, plastic crystals and liquid crystals can be produced based on variously shaped NP building blocks. [13][14][15][16][17][18][19][20][21][22][23][24][25][26] As a notable example, tetrahedra have been recently demonstrated to form various assemblies, including one-dimensional chiral tetrahelices, two-dimensional quasicrystals and three-dimensional cluster-based body-centred-cubic single supercrystals. [27][28][29][30] Despite great efforts devoted to non-spherical NPs, systematic self-assembly investigations on anisotropic NPs with peculiar geometries are still rare.…”

Release of Warfarin from Human Serum Albumin by Water‐soluble CdSe Nanotetrapods

“…Tip to tip self-assembly with 3D network of water soluble CdSe nanotetrapods have potential applications in photovoltaic devices, sensors as well as in catalysis. [58] Additionally, CdSe nanotetrapods can be used for biosensing if its arms can be functionalized with different proteins. [59] With this background, we have investigated the interaction of MPA-capped CdSe nanotetrapods with human serum albumin (HSA), with a focus on the possibility of displacement of bound ligands like warfarin [36,60,61] from HSA by its interaction with these nanocrystals.…”