9 research outputs found
Programmed Self-Assembly of Branched Nanocrystals with an Amphiphilic Surface Pattern
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
Additional file 1: of Development of the Japanese Core Outcome Measures Index (COMI): cross-cultural adaptation and psychometric validation
Japanese version of the Core Outcome Measures Index. Japanese version of the Core Outcome Measures Index in Japanese. (PDF 232 kb