Synthesis of Segmented Silica Rods by Regulation of the Growth Temperature

Abstract

The control of the diameter of colloidal structures is of fundamental interest and practical importance. We synthesized segmented silica rods by regulating the reaction temperature while the rods were growing. With higher growth temperatures, the segment diameter became smaller. Longer incubation times gave longer segments at the same temperature. Similarly, high temperature for the same incubation time gave longer segments. It appears that the correlation between temperature and diameter results from the relation between temperature and the size of the emulsion droplet, that is, the higher the temperature, the smaller the emulsion droplet.

Synthesis and Liquid-Crystal Behavior of Bent Colloidal Silica Rods

“…TEM images in Figure 3 show that, upon increasing the reaction temperature, the emulsion droplet attached at one end of the rods shrank, as a result of the dissolution of water emulsions in pentanol due to increased solubility at elevated temperature. 14b The temperature dependence of emulsion size was further confirmed by dynamic light scattering (DLS) analysis (Figure S7). DLS result shows that the size of emulsions containing all reagents except TEOS decreased with increasing temperature.…”

“…8a,f,14 In this synthesis, the hydrolysis and condensation of tetraethoxysilane (TEOS) at the interface of water emulsions lead to the anisotropic growth of silica rods tightly bound to one side of the emulsion in the presence of a structure-directing agent. Inspired by recent research, 8a,14b we present a novel synthetic strategy to produce monodisperse bent silica rods (BSRs) with tunable bending angle ( α ) and length ( L ) of each arm. This one-pot synthetic strategy utilizes temperature or pH variation to perturb the emulsion attached at one end of the rods and hence to induce the deviation of otherwise straight growth of silica rods to generate BSRs (Scheme 1a).…”

Positioning growth of scalable silica nanorods on the interior and exterior surfaces of porous composites

“…Our strategy was inspired by the wet-chemical synthesis method reported by Kuijk et al 15 Compared to previous synthesis methods, 16 this one-pot approach results in a high yield of particles and makes it possible to create dispersions with high nanorod concentration. [17][18][19][20] The silica nanorods have been widely adopted in a variety of areas, including information-encoded colloids, 21 permanent dipoles, 22 three-dimensional anisotropic architectures, 23 supracolloidal structures, 24 liquid crystals, 25,26 plastic crystals, 27 and reinforcements for matrix materials. [17][18][19][20] The silica nanorods have been widely adopted in a variety of areas, including information-encoded colloids, 21 permanent dipoles, 22 three-dimensional anisotropic architectures, 23 supracolloidal structures, 24 liquid crystals, 25,26 plastic crystals, 27 and reinforcements for matrix materials.…”

Synthesis of Half‐Sphere/Half‐Funnel‐Shaped Silica Structures by Reagent Localization and the Role of Water in Shape Control

“…[1,2] However, there have been only af ew efforts to control the shapes of microstructures. [5][6][7] Similarly, cone-shaped rods have been synthesized by etchingt he straight rods. [4] Rod shape has been furthermodified by using strategies such as temperatureor alcohol-induced change in the emulsion droplet size and the use of metal oxide nanoparticles.…”

“…[13] The rods have been also self-assembled and growno np orous composites. [5,6] Similarly,t here are no reports in the literaturea bout shape control and formationo fs tructures of increased complexity by localizing the reagents in the emulsion droplet. [16] However,afew efforts have been made to understand the underlying mechanisms related to the effects of different reagents on rod growth.…”