Synthesis of Snowman‐shaped Photocatalytic Microrotors and Mechanical Micropumps

Abstract

We synthesize snowman‐shaped microrotors that are composed of TiO2 and SiO2 particles fused together and half‐coated with Au. The microrotors rotate in the presence of fuel and UV light and the rotation speed is readily modulated by the fuel concentration and the light intensity. Such a microrotor can be transformed into a mechanical micropump that hydrodynamically, rather than electrokinetically, pumps nearby fluids and particles, with a pump power that scales linearly with its rotation speed. This work thereby opens up a new way for the study of microrotors as micropumps.

Covalent Organic Frameworks Based Inorganic/Organic Composite Materials for Photocatalytic Applications

“…At the same time, molecules could be highly soluble in SC fluid. Therefore, the SC fluid is an environmentally friendly alternative to organic and aqueous solvents [30] . For instance, Liu et al.…”

“…Therefore, the SC fluid is an environmentally friendly alternative to organic and aqueous solvents. [30] For instance, Liu et al first reported a close-connected TiO 2 /COFs composite material prepared by the supercritical CO 2 (SC CO 2 ) method. [31] COFs (TbBd) were dispersed in ethanol containing tetrabutyl titanate (TBT), and the compressed CO 2 was then pumped into the reactor with a small amount of water (5.52 MPa).…”

Synthesis of Rod-Shaped ZnO/Polysiloxane Micromotors with Patch-Dependent Motion Modes

“…12−15 For example, by electrochemical deposition, a gold layer is half-coated on twinned microrods or snowman-shaped particles and both the geometric and chemical symmetries are broken. 14,16 This thereby can lead to well-controlled and interesting self-rotational motions of the micromotors, which facilities many practical applications, such as cargo delivery and micropumping. 14,16 Although such a deposition method has been used to fabricate micromotors, it suffers from many drawbacks, such as complicated procedures and low yields.…”

“…14,16 This thereby can lead to well-controlled and interesting self-rotational motions of the micromotors, which facilities many practical applications, such as cargo delivery and micropumping. 14,16 Although such a deposition method has been used to fabricate micromotors, it suffers from many drawbacks, such as complicated procedures and low yields. The development of simple and effective strategies to synthesize micromotors with distinct geometric and chemical symmetries is highly desirable, yet remains challenging.…”

“…The anisotropic shapes break the geometric symmetry, and the composite particles composed of at least two types of materials break the chemical symmetry. A common method realizing such an approach is coating a metal layer on prefabricated anisotropic-shaped particles by electrochemical deposition or physical vapor deposition. − For example, by electrochemical deposition, a gold layer is half-coated on twinned microrods or snowman-shaped particles and both the geometric and chemical symmetries are broken. , This thereby can lead to well-controlled and interesting self-rotational motions of the micromotors, which facilities many practical applications, such as cargo delivery and micropumping. , Although such a deposition method has been used to fabricate micromotors, it suffers from many drawbacks, such as complicated procedures and low yields. The development of simple and effective strategies to synthesize micromotors with distinct geometric and chemical symmetries is highly desirable, yet remains challenging.…”