Arresting, Fixing, and Separating Dimers Composed of Uniform Silica Colloidal Spheres

Abstract

When fresh tetraethylorthosilicate is introduced into a colloidal suspension of silica spheres, it hydrolyzes and condenses in situ to arrest and fix the dimers resulting from constant collisions between the spheres. By optimizing the experimental parameters (including the length of aging time) and the diameter of the silica spheres, as well as the concentrations of counterions, water, and ammonia, it is possible to routinely produce monodisperse dimers with a yield as high as 50 %. When combined with centrifugation using a density gradient medium, the yield of such dimers could be further increased to 80 %. It is believed that this method will provide a simple and versatile approach to the high‐volume production of dimers from spherical colloids composed of different materials. These dimers may find widespread use in a range of applications such as fabrication of photonic crystals and fundamental studies related to colloidal science.

Dimerization of Colloidal Particles through Controlled Aggregation for Enhanced Properties and Applications

“…Controlled destabilization is not exclusive to metal nanocrystals. In fact, as an earlier example, we demonstrated that silica spheres could be systematically dimerized by introducing a relatively high concentration of fresh tetraethylorthosilicate (TEOS) (Figure A and B) . The hydrolysis products of TEOS resulted in a rapid reduction in the repulsive energy barrier, leading to dimerization mainly during the initial stage of the synthesis.…”

“…81 % trimers out of 1560 particles analyzed (Figure 8 c). In a separate study, we found that the yield of silica dimers, as shown in Figure B, could be increased from 50 % to 80 % after the sample had gone through separation involving a sucrose gradient and centrifugation …”

Conjugation of Colloidal Clusters and Chains by Capillary Condensation

“…A series of 2D composite clusters and a 1D-connected colloid chain are shown in Figure . Previously such composite clusters were synthesized through coassembly of “backbone” colloids and secondary materials, such as nanoparticles or liquid precursors. , The spatial selectivity of capillary condensation is evident from the observation that the templated organosilicate phases (bright bands) reside predominantly between adjacent spheres, different from previous reports, where coassembly led to uniform silicate coatings on the clusters. , …”

Synthesis of Copper–Silica Core–Shell Nanostructures with Sharp and Stable Localized Surface Plasmon Resonance

“…During the coating process, the peak at 700 nm was gradually recovered while the peak at 615 nm shifted to the blue, indicating that the nanostructure agglomerates were separated to yield individual nanostructures. After coating with SiO 2 , the nanorods could potentially be separated from the nanoparticles based on their difference in mass using centrifugation. , …”