Synthesis and Liquid-Crystal Behavior of Bent Colloidal Silica Rods

Abstract

The design and assembly of novel colloidal particles are of both academic and technological interest. We developed a wet-chemical route to synthesize monodisperse bent rigid silica rods by controlled perturbation of emulsion-templated growth. The bending angle of the rods can be tuned in a range of 0–50° by varying the strength of perturbation in the reaction temperature or pH in the course of rod growth. The length of each arm of the bent rods can be individually controlled by adjusting the reaction time. For the first time we demonstrated that the bent silica rods resemble banana-shaped liquid-crystal molecules and assemble into ordered structures with a typical smectic B2 phase. The bent silica rods could serve as a visualizable mesoscopic model for exploiting the phase behaviors of bent molecules which represent a typical class of liquid-crystal molecules.

Finite‐Sized One‐Dimensional Silica Microstructures (Rods): Synthesis, Assembly, and Applications

“…In other developments, Yang et al. synthesized bent silica rods by varying the reaction temperature (Figure c) . Room temperature gave straight segments whereas an increase in temperature resulted in a bent segment.…”

“…may not have done the sharp cooling and thus even if sample is removed from high temperature, it comes back to normal temperature slowly. Therefore, the use of partially hydrolyzed TEOS and slow cooling may be the reasons that resulted in a bent segment instead of a straight segment . By exploiting the sodium hydroxide based etching of preformed smooth silica rods, Hagemans et al.…”

“…Reproduced with permissions from Ref. . Copyright (2012, 2015, 2015, 2016) American Chemical Society.…”

Anisotropic Colloids: From Non‐Templated to Patchy Templated Synthesis

“…The synthesis is simple and reproducible, and can be used to prepare rods with an aspect ratio up to 25 on a large scale. Following this work, several kinds of other silica rods were synthesized by other research groups (Figure g,h) …”

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

“…[5][6][7] Similarly, cone-shaped rods have been synthesized by etchingt he straight rods. [10] Similarly,c omplex hierarchical structures have been made by growing ther ods on preformed particles such as silica, titania, and gold. [9] By combiningt he reactionp Hw ith temperature manipulation, bent rods have also been synthesized.…”